Posts Tagged ‘insecticide’

phenazocine A synthetic morphine-like analgesic, with similar properties and uses, but with a more rapid and prolonged action. It is of value in biliary colic, as it is less likely to cause a rise in biliary pressure. Dose: 20-30 ing daily, orally or subling tially, although single doses as high as 20 mg are sometimes given. The side-effects are similar to those of morphine and related drugs, but sedation and the risk of dependence is less. (Narphen).
I Phe
Dose: oo- 180 ing daily, at night, adjusted lo need and response. In severe conditions, doses of 50-200 mg may be given by i.m. or i.v. injection. Side-effects include drowsiness and skin reactions. In the elderly it may cause confusion, and paradoxically it may give rise to hyperkinesia in some children. See page 136 and Table 15.
phenol Once widely used as a general antiseptic. Weak solutions relieve itching, and phenol is present in Calamine Lotion. A 5% solution in almond oil is used for the iniection treatment of haemorrhoids.
phenelzine A monoamine oxidase inhibitor, used in the treatment of depression. Dose: 45-60 ing daily, according to need and response. It has many side-effects, including dizziness. dry mouth and blurred vision. Very severe hypertension has been precipitated by some foods, notably clicese. Care is necessary in cardiovascular disease and epilepsy. It may also potentiate the action of other drugs on the central nervous system. (Nardil). See monoamine oxidase inhibitors, Page 128 and’I'able 11.
phenindamine An antihistamine ofinedium potency. It differs from most antihistamines in having a mild central stimulant action, and so rarely causes drowsiness.
Dose: 75-200 ing daily. IThephorin). See page I 10 and Table 2.
phenindione An orally active anticoagu last used in the control of deep-vein thrombosis.
Dose: 200 mg initially; maintenance, 25-100 mg daily, depending on laboratory reports of the prothrombin time. Side- effects include hypersensitivity reactions and haemorrhage. Patients should be warned that the drug may colour the urine. Phenindione has now been largely replaced by %varlarill, (Dindevan).
pheniramine An antihistamine similar to but less potent than chlorpheniramine. Dose: 150 ing daily. (Daneral SA). See page 110 and Table 2.
tphenobarbitone A powerful sedative, hypnotic and anticonvulsant drug. It is mainly of value in epilepsy, as it is effective in most types of seizure except petit mil (absence seizures).
phenolphthalein A synthetic laxative. It is sometimes given with emulsion of liquid paraffin.
Dose: 50-100 mg daily. It may occasion alit/ cause a rash, and its use has declined.
tphenoperidine A narcotic analgesic, often used in association with droperidol in neuroleptanalgesia. It is also used as a supplementary analgesic in general anaesthesia.
Dose: 0.5-1 mg i.v. with subsequent doses as required. It may cause respiratory depression, which can be controlled by doxapram or naloxone. (Operidine).
phenothrin An insecticide used as 0.2% lotion for head and crab lice. (Fill] Marks).
phenoxybenzamine An alpha-adrenoceptor blocking agent used in the severe, episodic hypertension associated with phaeochroniocytoma.
Dose: orally and by injection, 10–20 mg according to need and response. Side-effects include dizziness and tachycardia; rapid and marked hypotension after injection. (Dibenyline).
phenoxymethylpenicillin An orally active, acid-stable penicillin, also known as penicillin V. It is used mainly in respiratory infections in children, in tonsillitis, and to supplement injection treatment. It is not suitable for use in severe infections. Dose: I - 2 g daily, before food. Doses of .500 mg daily are given in rheumatic fever and pneumococcal prophylaxis.
tphentermine An appetite depressant given ill the short-term treatment of obesity. Dose: 13–30 mg before breakfast. (DUramine: lonamin).

phentolamine An alpha-adrenoceptor blocking agent that can temporarily reverse the vasoconstrictive action of adrenaline and noradrenaline. It is used mainly in the diagnosis and control of the episodic hypertension of phaeochromocy- toma, and during surgical removal of the tumour.
Dose: 2-5 ing i.v. repeated as required. Side-effects are tachycardia, hypotension, dizziness, nausea and diarrhoea. (Rogitine).
phenylbutazone A powerful, non-steroidal anti-inflammatory agent, formerly used in the treatment of rheumatic and arthritic conditions. Because of blood dyscrasias, which may occur suddenly, the drug is now used only for the treatment of ankylosing spondylitis under hospital supervision.
Dose: 400-600 mg daily. (Butacote). See page 165 and Table 29.
phenylephrine A vasoconstrictor similar to .”Irvildlille, but less toxic. Given in acute hypotensive states.
Dose: 5 mg by i.m. injection, or 100-500 pg by slow i.v. injection. Sometimes valuable in paroxysmal atrial tachycardia. It is also used locally as 1:400 solution as nasal decongestive, and as eye drops, 2.5-100/6.
phenylpropanolamine A sympatho11111lictic agent used with other drugs in preparations for the symptomatic relief of nasal congestion.
phenytoin An anticonvulsant used in all forms of epilepsy with the exception of petit mil (absence seizures). It has little hypnotic effect and combined treatment with phenobarbitone may evoke the best response.
Dose: 150-600 mg daily with or after food. In status epilepticus it is given under ECG control in doses of 10-15 mg/kg by slow i.v. injection. It is also given to control ventricular tachycardiac in doses of 3.5-5 mg/kg by slow i.v. injection via a cavil catheter. The side-effects of
extended treatment are numerous, and include rash, dizziness, blood dyscrasias, hirsutism and gingival hypertrophy. (Epanutin). See page 136 and Table 15.
pholcodine A cough centre depressant resembling codeine, but it lacks any analgesic properties. It is present in a range of
products used for the relief of useless cough, and has the advantage over codeine of not causing constipation.
Dose: 10-60 mg daily.
physostigmine A plant alkaloid, also known as eserine, once used as a miotic (0.25-1%) to counteract the effects of atropine.
phytomenadione Vitamin K,. The form of vitamin K used in the prophylaxis and treatment of neonatal haemorrhage due to vitamin K deficiency.
Dose: I mg by i.m. injection. It is also of value in the haemorrhage due to overdose of oral anticoagulants. Dose: 10-40 mg by slow i.v. injection. In less severe condi-
tions, 10-20 mg orally, according to the base-line prothrombin time. (Konakion).
pilocarpine A plant alkaloid with a miotic action similar to, but less intense than that of physostigmine.
Dose: in glaucoma as eye drops of 0.5-41!4,, 3-6 times a day. Occasionally given in doses of 15-30 mg daily with food to reduce the dry mouth associated with irradiation of the head and neck.
(Salagen). See page 138 and Table 16.
pimozide A tranquillizer with the actions and uses of chlorpromazine. It is used mainly in the treatment of schizophrenia, as it reduces the delusions without causing drowsiness.
Dose: 10 mg daily initially, adjusted up to a maximum of 20 ing daily, with maintenance doses according to response.
Similar doses are given in mania and psycho-motor agitation. The side-effects are similar to those of chlorpromazine. (Orap). See page 168 and Table 30.
pindotol A beta-receptor blocking agent, with actions and uses similar to those of propranolol. Less likely to cause bronchospasm.
Dose: 7.5-15 nig daily. (Visken). See page 148 and Table 2l.
piperacillin A semi-synthetic penicillin with a wide range of activity that extends to Pseudomonas and anaerobes. It call be used in association with other antibiotics in life-threatening and multiple infections. Dose: in severe infections, 200-300mg/kg daily by i.m. or slow i.v. injection or infusion, increased in life-threatening infections to 16g daily. In less severe infections, 100-150ing/ki; i.m. daily, with a maximum single dose of 2g. (Pipril). Sometimes given with the beta-lactamase inhibitor tazobactam as the mixed product Tazocin.
piperazine An effective anthelmintic against threadworms and roundworms. Dose: 2-4 years, 750 ing; 5-12 years, 1.5 g; in children over 12 years and in adults, 2 g; as a single daily dose for 7 days, repeated if necessary after I week. For roundworm, a single dose of 4 g is given, but as the worms are narcotized, and not killed, a purgative is necessary to ensure expulsion. Side-effects are nausea, diarrhoea and occasional dizziness. Care is necessary in renal impairment, epilepsy and psychiatric conditions.
I Pot
Dose: 1.5-3 nig daily. Side-effects include drowsiness, nausea, dizziness and weight gain. (Sanomigran). See page 154 and Table 23.
podophyllum resin A plant extract used topically as a paint (0.5-25% in alcohol) for anogenital and plantar warts. It is very irritant to normal tissues, and its use requires care. (Condyline; Warticon).
polygellne A modified gelatin, used with sodium chloride and other electrolytes as a [)food volume expander.
Dose: 500-1000 ml by i.v. infusion. (1-lacniaccel).
polynnyxin 8 An antibiotic used by local application for infections of the car, eye and skin. It is too toxic for systemic use.
pipothiazine A chlorpromazine-like drug, with similar uses and side-effects, but given mainly as a depot preparation for the maintenance treatment ofschizophreiiiii. Dose: Wier a test dose of 25 mg) 50-IMnig by deep i.m. injection every 4 weeks, increased if necessary up to a maximum of 200 mg per dose. (Piportil Depot)• See page 168 and Table 30.
piracetamV A new drug used for the treatment of the spasmodic condition cortical myoclonus.
Dose: 7-20 g daily. Side-effects include diarrhoea, nervousness and rash. (Nootropil).
piroxicam A non-steroidal anti-inflammatory agent (NSAID) with all extended action, and used in arthritis, spondylitis, gout and musculoskeletal disorders. Dose: 20-30 mg daily; up to 40 ring daily in gout and other acute conditions. It is also used for local application as a 3% gel. As with related drugs, side-effects include gastrointestinal disturbances of varying severity, especially with higher doses. Weldene). See page 165 and Table 29.
pivampicillin A derivative of ampicillin, with similar actions and uses. Is hydrolyzed to ampicillin after absorption, but gives higher blood levels. Much is excreted in the urine, so it is of value in urinary infections. Dose: I -2 g daily. (Pondocillin).
pizotifen A serotonin antagonist used in the prophylaxis of migraine, and vascular headache.
polymyxin E See colistin.
polystyrene resin An ion-exchange resin [or the removal of potassium in
conditions associated with hyperkalaemia, as in oliguria and anuria.
Dose: 15 g 3•4 times a day according to the plasma level of potassium. When the drug is not tolerated orally, 30 g daily as a suspension may be given per rectum. Care is required in renal or hepatic impairment. (Resonium).
polythiazide A potent diuretic with the action, uses and side-effects of the thiazide diuretics but effective in the low dose of 1-4 ing daily. (Nephril).
poractant A lung surfactant used in the respiratory distress syndrome of premature infants. It is given by endotracheal tubing with mechanical ventilation.
(Curosurf).
potassium One of the most important ions of the body, mainly present in intracellular fluid. Many diuretics increase loss of potassium as well as sodium; with extended
treatment the potassium balance may be disturbed, with acute muscle weakness, cardiac arrhythmias, and an increased sensitivity to digitalis. Potassium loss can 1-w treated with potassium chloride orally (often as Slow-K, but may cause peptic ulceration), or by effervescent potassium tablets. Mixed diuretic and potassium products are also available.

lithium succinate Lithium succinate appears to have sonic antifungal and anti-inflammatory properties, and is used as an 8% ointment for seborrhoeic dermatitis. (Ftalith).
lodoxamide A mast cell stabilizer similar to sodium cromoglycate. Used as eye drops (0.1%) in allergic conjunctivitis. (Alomide).
Dose: in acute diarrhoea, 4 mg initially, followed by 2 nig as required, up to a maximum of 16 ing daily. In chronic diarrhoea, 4-8 nig daily, but care is necessary in the elderly to avoid faecal impaction. Loperamide is not suitable for children under 4 years of age, nor in patients with liver disease, as it may cause undesirable sedation. (Iniodium).
loprazolam A benzodiazepine hypnotic used mainly in the short-term treatment of insomnia and nocturnal arousal. Dose: 1-2 nig at bedtime. Side-effects include drowsiness, dizziness, dry mouth and headache. See page 152 and Table 22.
loratadine An antihistamine with the general action of that group of drugs, but with reduced sedative side-effects.
Dose: 10 nig dailv. (Clarityn). See page I 10 and Table 2.
63
lofepramine An antidepressant of the irnipramine group, with similar actions and uses, but reduced sedative and anticholinergic side-effects.
Dose: 140-210 nig daily. (Gamanil). See page 128 and Table 11.
lofexidine A narcotic antagonist. It has a selective blocking action on brain nor-adrenaline, and is used for the rapid relief of opioid withdrawal symptoms associated with central sympathetic activity.
Dose: 200 pg twice a day, slowly increased as required over 7-10 days, before withdrawal over 2-4 days. Care is necessary in cardiac insufficiency and bradycardia. (Britl.olex).
lomotil A preparation of diphenoxylate with atropine, for the rapid control of diarrhoea. Dose: 2 tablets 6-hourly.
lomustine A slow-acting cytotoxic agent used in Hodgkin’s disease and solid tumours.
Dose: 130 ing/ni’body surface at intervals of (> 8 weeks. Side-effects, include anorexia. nausea, liver damage and niyelodeprm ion. Dosage should not be repeated until white cell and platelet counts have returned to an acceptable level. Reduced doses are given
when lomustine forms part of a multi-drug dosage scheme. (CCNU). See page 122 and Table 8.
loperamide A synthetic inhibitor of peristalsis.
lorazepam A short-acting anxiolytic/ hypnotic similar to diazepam, but less likely to cause next-day drowsiness. Dose: 1-4 mgdaily. It is also given in similar oral closes or by slow i.v. injection in doses of 50 pglkg for preoperative sedation and anuiesia. Occasionally used i.v. in status epilepticus in doses of 4 nig, but apnoea and hypotension are side-effects that may require resuscitation. fAtivan). See page 152 and Table 22.
lormetazepam A short-acting benzodiazepine hypnotic. It is useful in the treatment of insomnia in the elderly, but is less suitable for insomnia associated with early awakening.
Dose: 500 fig I nig at night. See page 152 and ‘]’able 22.
losartanV An angiotensin 11 receptor antagonist used in the treatment of hypertension.
Dose: 50ing daily The use of potassium-sparing diuretics should be avoided with losartan. It has the advantage of not causing the persistent dry cough associated with ACE inhibitors. (Cozaar). See page 148 and Table 21.
low molecular weight heparins See heparin.
loxapine Antipsychotic agent with the actions and uses of chlorpromazine. Dose: in acute and chronic psychoses, 25-50 mg daily, slowly increased as required. Maintenance doses range from 20-100111g daily. Side-effects are those of other anti-psychotic agents. but loxapine may cause nausea, vomiting and weight changes. f .oxapac). See page 168 and Table 30.
I Mob
magnesium hydroxide A mild antacid laxative, usually given in aqueous suspension as Cream of Magnesia, although tablet forms are also available. Cream of Magnesia is a useful antidote in mineral acid poisoning.
64
Lugol’s solution An aqueous solution of iodine 5% and potassium iodide 10%. Used in the preoperative treatment of t hyrotoxicosis.
Dose: 0.3-1 ml.
lymecycline A soluble complex of tetracycline and lysine. It has the action and uses and side-effects of tetracycline, but is absorbed more readily.
Dose: 800 mg daily. (Tetralysal).
typressin An analogue of vasopressin used to control the polyuria of pituitary diabetes insipidus.
Dose: 2.5-10 units several times a day by nasal spray. Side-effects include nausea and abdominal pain. I.ypressin has some vasoconstrictor properties, and desmopressin is sometimes prellcrred. (Syntopressin).
lysuride (lisuride) A bromocriptine-like drug for the treatment of parkinsonism. II acts by stimulating any surviving dopamine receptors in the brain.
Dose: 200 pg at night with food,
irk ceased at weekly intervals according to response up to a maximum of 5 mg daily. Side-effects include nausea, dizziness and initial hypotensive reactions which may affect driving ability. (Revanil). See
page 160 and Table 26.
magnesium sulphate Epsom salts. A powerful saline aperient, producing loose stools by preventing the reabsorption of water.
Dose: 5- 15 g before breakfast. Used externally for the treatment of boils and carbuncles as a paste with glycerin. A marked loss of plasma magnesium may occur after severe diarrhoea or drug-induced diuresis, and may require the i.v. infection of magnesium sulphate in doses based on the degree of hypoinagnesacmia. It has also been given i.v. in a dose of 8 mmol in the emergency treatment of severe;U’rhythinias associated with hypokalaemia.
magnesium trisilicate A white insoluble powder, with mild but prolonged antacid effects. It was formerly widely used in the symptomatic treatment of peptic ulcer;
now used chiefly for dyspepsia.
Dose: 0.3-2 g.
malathion An organophosphorus insecticide. Used as a lotion 0.5% for lice and scabies as alternative to lindane or carbaryl.
mannitol A sugar that is not metabolized, and is used mainly as an osmotic diuretic. Dose: (after a test dose of 200 mg/kg) 50-200 g by slow i.v. infusion over 24 hours. Mannitol has also been used by i.v. infusion as a short-term ocular hypotensive agent in the treatment of glaucoma. It is also useful in cerebral oedema, given by rapid i.v. injection in a dose of I g/kg as a 2044, solution.
macrolides A group of antibiotics that differ chemically from the penicillins, yet have a similar pattern of activity. They are active orally and are useful in the treatment of penicillin-sensitive patients. Erythromycin is the most widely used member of the group, with clarithromycin and azithromycin as more recent introductions.
magnesium carbonate A white, insoluble powder with antacid and laxative properties.
Dose: 0J-4 g daily.
maprotiline A sedative antidepressant with a general action similar to that of the tricyclic drugs represented by amitriptyline. Dose: 25-150 mg daily. If given at night as a single dose, the sedative action may reduce the need for other drugs. It has milder anticholinergic side-effects than some related compounds, although skin rash is more common. (I udionlil). See page 128 and Table 11.
mebendazole An anthelmintic effective against most intestinal worms.

Dose: 100 mg once for threadworm, and 100 mg twice daily for 2 days against other infestations. Generally well tolerated, but it should not be given to children under 2 years of age. (Verniox).
I Men
in oedematous states. A potassium supplement may be required. Care is necessary in renal and hepatic deficiency.
(KiYcaron). See page 148 and Table 21.
mebeverine An antispasmodic agent which, unlike the anticholinergic drugs, appears to have a direct action on the intestinal smooth muscle. It is useful in the treatment of gastrointestinal spasm and in the irritable bowel syndrome. Dose: .100 mg daily, before food. As with other antispasmodics, mebeverine should not be used in paralytic ileus. (Colofac).
medroxyprogesterone A synthetic progestogen.
Dose: in endometriosis 30 mg daily for 90 days; in dysfunctional uterine bleeding and secondary amenorrhoea: 2.3-10 mg daily for 5-10 days, starling on l6th-2 Ist day of cycle and repeated for 2-3 cycles. Large doses of 400 mg-1.5 g daily are given in breast, endometrial, prostate and other hormone-dependent cancers, or 250mg– I g weekly by deep i.m. inJection. (Farlutal; proves). Depot-proves is a long-acting product used by i.m. injection is a contraceptive. but only after fit][ counselling.
megestrol An orally active progestogen. It is used in oestrogen-dependent breast cancer, and acts by suppressing the uptake of oestrogens by the cancer cells.
Dose: 160 mg daily. Nausea and fluid retention with weight gain are occasional side-effects. (Megace). See page 122.
meloxicarn A recently introduced non-steroidal anti-inflammatory drug (NSAID) indicated in the short-term treatment of acute osteo-arthritis and the longer-term treatment of rheumatoid conditions. Dose: 7.5-15 mg once daily with food; half doses for the elderly. Suppositories of 15 mg are also available. The side-effects are basically those of the NSAI Ds in general. Meloxicam has a more selective action on cyclo-oxygenase, the enzyme involved in the biosynthesis of prostaglandins, and is less likely to cause gastrointestinal disturbance, but it has no cytoprotective action, and is not suitable for patients with peptic ulcer. (Niobic). See page 165 and Table 29.
65
mefenamic acid A non-steroidal anti-inflammatory analgesic agent used to relieve moderate pain in arthritic and rheumatoid conditions, and other states requiring mild analgesic therapy such as dysmenorrhoea. Dose: 1.5 g daily after food. Side-effects are drowsiness an(] haemolytic anaemia. Diarrhoea is an indication that the drug should be withdrawn. (Ponstan). See page 165 and Table 29.
rnefloquine A drug for the prophylaxis and treatment ofchloroquine-resistant malaria. Dose: lot- short -term prophylaxis 250 mg weekly, starting 1 week before exposure and for 4 weeks after return. Doses for treatment require specialist advice. Side-effects include gastrointestinal disturbances, dizziness and weakness. It is contraindicated in patients with a history of neu ro- psych iatric disturbance, and is not suitable for use in severe renal or hepatic impairment. (Lirium). See halofantrine.
mefruside A diuretic useful in the treatment of hypertension and oedema. Dose: 25-50 mg daily in the morning, according to need and response; 25-100 mg
melphalan An alkylating agent of the mustine type. Used mainly in myelomas, lymphomas and some solid tumours. Dose: 150-300 gg/kg daily for 4-6 days, repeated after 1-2 months. In myeloma it is also given by regional perfusion. The injection solution is highly irritant and contact should be avoided. Side-effects include myelo-depression, nausea, rash and pruritus. (Alkeran). See page 122 and ‘rabic 8.
menadiol A water-soluble form of vitamin K. Dose: 10 ing daily. (Synkavit) Phytorneii,dionc i.% now preferred.
menotrophin Human menopausal gonadotrophin containing follicle-stimulating hormone and luteinizing hormone. It is used in the treatment of anovulatory sterility. The dose depends on individual hormone assays and response. The use of the drug has resulted in multiple births. It is also given to males to stimulate spermatogenesis. (Humegon; Normegon).
menthol Colourless crystals obtained from oil of peppermint. Used as spray or drops for nasopharyngeal inflammation.

Air Pollution and Allergy

Air pollution plays a variety of roles in allergic reactions. Some pollutants irritate the nose and airways (and sometimes the skin) making them more sensitive to allergens. These pollutants can worsen existing allergic symptoms and may promote the development of allergies in children, by making the airway membranes more permeable. Other chemical pollutants may affect the immune system directly, increasing any existing tendency to allergic reactions.
Indoor pollution
For many of us, the air in our houses is much more polluted than any outdoor air. Several of the indoor pollutants irritate the nose and airways, and some can trigger asthma attacks. A few of the pollutants found indoors can also make allergies and asthma more likely to develop in young children.
Background pollution
One of the worst irritants in indoor air is tobacco smoke. Other people’s cigarette or pipe smoke can trigger asthma attacks in the short term, and makes asthmatics generally worse in the long run. Passive smoking might also affect the immune system making allergies more likely to develop, though this is not proven. Do whatever you can to eliminate tobacco smoke from your home.
Everyone is different
This article considers air pollution from the point of view of someone with classical allergies (e.g. hayfever or asthma). Those with chemical intolerance (see p. 84) may well be more severely affected by air pollution.
If you smoke yourself, there are many good reasons for giving up:
• If individuals from atopic families (see p. smoke, they have a far greater chance of developing allergies and/or asthma when exposed to an allergen in the air.
• For those who had asthma as children and have since grown out of it, cigarette smoking doubles the chance of it coming back.
• Parents of asthmatic children who smoke indoors make their children’s asthma worse. Teenagers can be just as badly affected by passive smoking as young children.
• Smoking during pregnancy significantly increases the risk of a woman’s baby developing allergies and asthma. (Smoking also leads to more prematurity, still-births and cot deaths.)
If possible, have an electric cooking stove rather than a gas one –or fit a powerful extractor fan. Cooking with a gas stove generates a lot of nitrogen dioxide, a gas that you can’t smell or see but which affects the airways. This same gas also comes from motor traffic, but peak levels of nitrogen dioxide in kitchens with gas cookers are often ten times the average level on city streets, and frequently exceed standards for outdoor air set by the world Health Organisation. Other sources of nitrogen dioxide include cigarettes, gas fires and kerosene-burning stoves.
For some people with allergies, nitrogen dioxide enhances their response to the allergen. So if you inhale dust-mite allergen together with nitrogen dioxide, it may have more effect than the Smoke screen
Smoke particles from coal or wood do not seem to make allergies more likely to develop - in fact, quite the reverse. In rural areas of Germany, researchers have found that children with coal or wood stoves in their homes were less likely to have allergies or asthma. An Australian study made a similar finding. Bronchitis and pneumonia are more common in those children with wood and coal stoves and these infections may stimulate the immune system in such a way that allergies are less likely to develop later. However, wood smoke may be a cause when asthma begins in an adult.
allergen alone. Breathing sulphur dioxide (see below) and nitrogen dioxide together boosts the reaction to allergen more powerfully than either gas alone.
Nitrogen dioxide might also make asthma attacks more likely, but the evidence on this is conflicting.
For young children, a high level of nitrogen dioxide at home may make the development of allergic reactions more likely. A recent Canadian study showed that children exposed to high levels of nitrogen dioxide in the home - usually from gas cookers - were ten times as likely to develop asthma as those breathing low levels of nitrogen dioxide. If a dog, cat or other furry pet was kept, and there were high nitrogen dioxide levels, the risk of developing asthma shot up even higher, to 25 times that of children with low nitrogen dioxide and no pets. (Other studies have not produced the same spectacular results, but their methods of measuring nitrogen dioxide exposure were less precise.)
Try to eliminate materials that produce formaldehyde fumes, or seal the items with a good coat of paint. Formaldehyde is given off by chipboard and to a lesser extent by MDF (medium-density fibreboard). Injected cavity wall insulation can also produce persistent formaldehyde fumes, and is very difficult to get rid of -moving out is often the only option. A recent study from Australia showed that children exposed to formaldehyde, especially in the bedroom, were more likely to develop allergic reactions: the higher the level of formaldehyde exposure, the more severe the child’s allergic sensitisation.
Those with asthma have more frequent symptoms if exposed to high formaldehyde levels. A recent study from Finland shows that easy-to-clean plastic wall-covering and flooring increases the risk of asthma in children.
A Canadian study found that children whose first home was less than 20-30 years old were 50% more likely to develop asthma than children living in older houses. One possible explanation for this lies with the materials used in the construction and fitting of new houses, especially the plastics, wood preservatives and insulation materials. Solvents, and chemicals such as formaldehyde, are still being given off by these materials some years later.
Air fresheners provoke asthma attacks in some people. For a few individuals they can cause general symptoms of ill-health that are similar to those described for mild chemical intolerance (see p. 84). Those affected generally don’t realise that the air freshener is the source of the trouble. This malign effect is not entirely surprising, since air fresheners work by giving off a chemical that targets part of the brain - the part involved in processing sensory input from your nose. The chemical ‘freshens the air’ by partially disabling your sense of smell. Better to open a window.
Cleaning products, furniture polish and deodorant were never intended to go into the nose and airways, but that’s what happens when they are sprayed from an aerosol, and they can trigger asthma attacks. Steer clear of aerosols as much as possible - there are usually alternatives.
Pollution peaks
Read the instructions and ingredients lists on all products carefully. It is not just a question of what’s in them, but also what gases they might give off when used. One asthmatic died within minutes when the de-rusting agent she was using on her dishwasher produced a large amount of sulphur dioxide gas: her airways tightened up so much that she couldn’t even use an inhaler to save herself. ‘Sulphuric’, ’sulphate’ or ’sulphite’ in the list of ingredients should ring warning bells if you have asthma: sulphur dioxide gas could be given off by this product.
Bleach, and other chlorine-based cleaning products, such as toilet cleaner and scouring powder, should be used sparingly, and with plenty of ventilation. These products release chlorine gas which, in large amounts, can irritate the airways of asthmatics. Never allow bleach or toilet cleaner to become mixed with any other product. Take care with any product containing hypechlorte, chloramine, ammonia, acids or morpholine and with the chemicals used for swimming pool water. All these can trigger asthma attacks.
If doing repairs or DIY work about the house, take special care. Always ventilate the work area well, and wear a dust mask if sawing or drilling.
The smell of paint is due to solvents, and these can act as irritants to the nose and airways. When decorating, ventilate well, and use low-odour water-based paint. Some of the best low-odour paints, tested and shown to be safe for paint-sensitive asthmatics, are only available by mall order: see p. 255.
‘Instant foam’ kits sold for DIY insulation can provoke asthma in those who were not asthmatic previously. Two different substances are mixed to create the polyurethane foam, and during the mixing process, isocyanate is released – this is one of the most powerful asthmagens known (see box on p. 132). The level of isocyanate can breach the safety limit set for factories.
Avoid using fly spray or other insecticides: look for other methods of pest control. A study from Ethiopia showed that people using an insecticide in their houses were twice as likely to develop allergies. A study of Canadian farmers suggested that asthma might be linked to the use of carbamate insecticides (e.g. carbofuran). The sprays used for cockroaches can act as irritants for those with allergic rhinitis or chronic sinusitis.
If advised that your house needs spraying with insecticide, for woodworm or other wood-boring pests, ask for more information before you go ahead. Is the spraying really necessary? What will happen if the house isn’t sprayed? How quickly will it happen? Is there any other method of eradicating the pest? Spraying is often done when it is not really essential – houses remain standing even with woodworm holes all over them. Unless you have a heavy infestation that is threatening the structure of the house, you are probably better off not having the house sprayed. The heavy and ongoing exposure to insecticide that spraying of a house involves is something you and your family should avoid if at all possible. All the sprays used are toxic to some extent – don’t believe those who tell you otherwise. A heavy exposure to pesticides can sometimes make allergic symptoms worse or precipitate chemical intolerance (see p. 85).
The garage, workshop or garden shed can also be very polluted. Petrol, kerosene and paraffin can affect some people with rhinitis or asthma, and can bring on their symptoms. These fuels should always be kept in airtight containers. Paints sold for cars often contain isocyanates, among the most common causes
of work-related asthma (see box on p. 132). If using such paint, wear a mask with an activated carbon filter and make sure the area is well ventilated. Avoid prolonged or repeated exposure.
Outdoor pollution
Some of the pollutants in outdoor air can make allergic reactions worse and can trigger asthma attacks in people who are already asthmatic. A study of hospital admissions in London, Paris. Barcelona and Helsinki found that high levels of pollution increased hospital admissions for asthma by about 3%.
The pollutants that matter to those with allergies are:
• ozone, which soars to high levels on sunny days, mainly in country areas that are near large cities. The reason for this is a chemical reaction which occurs when car exhaust fumes are exposed to sunlight, producing ozone, a highly reactive form of oxygen. Further chemical reactions, involving another ingredient of exhaust fumes, then break the ozone down again. Thanks to this second reaction, there is usually little ozone in city air. But in a relatively rural area 20 miles or so upwind of the city, the pollutants are too dispersed for the second reaction to occur, and the ozone from the urban traffic can accumulate.
Ozone levels in the air tend to peak in the late afternoon and early evening – but it takes 4-24 hours for ozone to produce its effects on the airways. Indoors, ozone breaks down very quickly because of contact with other gases inside the house.
Ozone can increase the effects of allergens, such as pollen, on the nose and airways.
In addition, ozone makes the airway muscles contract, even for people without asthma. Healthy people tend not to notice these effects, whereas some asthmatics may have more symptoms, and may need more drugs, on days when ozone levels are unusually high.
• diesel particulates, which can become a problem in town centres, and close to main roads used by vans and lorries. Unlike ordinary petrol, diesel fuel contains oil, so when it burns it produces tiny black particles. These consist of flakes of carbon (soot), coated with complex chemicals that are produced by the
But what about the ozone layer…?
Is ozone good for us or bad for us? People often get confused about this, because of all the discussion about
‘the destruction of the ozone layer’. But that ozone layer (which screens us from harmful ultraviolet light) is a natural phenomenon and it is thousands of feet up, well away from our lungs. At ground level, in the air we breathe, ozone is unnatural and potentially damaging .
The size of the particles
Diesel particles are 1-10 microns in size, with most smaller than 2.5 microns. Tobacco smoke, coal smoke, fumes from oil-burning boilers, and the smoke from frying food all contain very much smaller particles, down to a hundredth of a micron (.01 microns) in size. (A micron is a thousandth of a millimetre.)
In pollution reports, counts for particles in the air (mostly diesel particles these days, except in heavily industrialised areas) will often appear as ‘PM1 0′, meaning ‘Particulate Matter less than 10 microns in diameter’. This particle size is chosen because larger particles tend to settle in the nose and throat, and not reach the airways of the lungs. The term ‘Small Particles’ is sometimes used to mean PM10.
To deal with air pollution, you need a really good mask with two filters: a dust filter that can take out very small particles and an activated carbon filter that absorbs irritant fumes and gases. Note that while activated carbon filters remove most pollutants, they do not take out nitrogen dioxide unless they have been specially treated.
partial combustion of the oil. It is probably these surface chemicals, rather than the soot particles themselves, that have such bad effects on the nose and airways.
Some research suggests that diesel particulates might increase the risk of allergies developing – to pollen for example. Additionally, when levels of diesel particulates are high, asthmatics tend to have more symptoms. If levels rise above 50 micrograms per cubic metre there is a sharp increase in asthma attacks – and a recent study in Birmingham showed that such levels are regularly reached at roadsides.
• sulphur dioxide, which often reaches high levels in areas of heavy industry, particularly near coal-fired power stations and coking plants. It acts as an irritant to the airways and can trigger attacks in asthmatics, who are far more sensitive to sulphur dioxide than healthy people (see box on p. 207). However, at the sort of concentrations normally encountered, even in quite polluted air, sulphur dioxide does not have any effect on most asthmatics.
• nitrogen dioxide, which is produced by all types of vehicles, and by power stations and some factories. In towns and cities with heavy traffic, nitrogen dioxide can build up to high levels. This gas is also found indoors (see p, 128) – often at far higher levels.
Oil refineries and cement works
In addition to these widespread pollutants, there are localised areas of air pollution, around industrial sites, that are frequently accused of causing health problems, including high rates of asthma. The kinds of industrial sites regularly mentioned include:
• oil refineries and oil-burning power stations
• cement works that use waste solvents for fuel
• dock areas where oil is loaded into tankers.
None of these accusations has been investigated in any detail, so it is impossible to say if there is a real link with asthma.
Avoiding outdoor air pollution
If you live in the kind of area that experiences high levels of ozone (see p. 130), plan your outdoor activities, especially jogging or playing sport, to avoid summer afternoons and early evenings.
Those who live very close to a main road, with a lot of lorries going past, would probably improve their own health, and reduce the chance of their children developing allergies and asthma, by fitting air conditioning or high-quality HEPA air filters – or by moving house. However, the benefits, in terms of decreased risk, are not enormous, and it is important to take other preventive measures as well (see Chapter 8).
When driving, if you stop behind a lorry or bus, keep your distance, close the window and turn off the fan. Diesel vehicles often emit a thick cloud of particles as they set off, and this can come straight into your car, setting off severe attacks for some asthmatics.
A car with air conditioning will reduce your exposure to diesel particulates while driving. When buying a new car, you can make a contribution to air quality by choosing a non-diesel vehicle, preferably one with a catalytic converter fitted. Alternatively, buy a diesel vehicle with a particle filter on the exhaust (now fitted as standard in Germany).
In Britain, the Vehicles Inspectorate of the Department of Transport encourages the public to report lorries and buses seen pumping out black smoke (look in the phone book for the number).
If you are asthmatic, breathing through your nose may help as this can filter out some damaging pollutants before they reach the airways in your lungs. (If your nose is usually blocked, try the exercises on pp. 230-31).
When levels of ozone or sulphur dioxide are high, taking a supplement of Vitamin C and eating plenty of foods that contain Vitamin E and beta-carotene (see p. 207) can protect your airways.