halothane A potent non-inflammable inhalation anaesthetic. It suppresses mucous and bronchial secretions, and reduces capillary bleeding. It has sonic muscle-relaxant properties, but in major surgery, supplementary treatment with a muscle relaxant is necessary. Halothane may cause some cardiac irregularities, but an occasional serious side-effect is severe hepatotoxicity, particularly after further exposure to the drug within periods of 441 weeks. Such susceptibility cannot yet be detected, so great care is necessary in any cases of liver dysfunction.
(Fluothane).
hamamelis An extract of witch hazel leaves referred to as harnarnelis or witch hazel water is used as a soothing application for bruises and sprains.
Hartmann’s solution An electrolyte-replacement solution containing sodium lactate, sodium chloride, potassium chloride and calcium chloride.
heparin The natural anticoagulant obtained front lung and liver tissue. It is widely used in deep-vein thrombosis and pulmonary embolism.
Dose: by i.v. injection 5000 units initially, followed by 1000-2000 units hourly by i.v. infusion, or 15000 units by s.c. injection 12-hourly under laboratory control. Prophylactic dose before surgery 5000 units, then 5000 units every 8-12 hours for 7 days. Overdosage call be controlled by the i.v. injection of prolamine sulphate. Treatment with heparin may be combined with that of oral anticoagulants such as phenindione or warfarin to provide immediate action before the slow-acting oral drugs begin to take effect. Occasional side-effects include hypersensitivity reactions and alopecia. Heparin is a complex polysaccharide, but certain fragments of that large molecule retain sonic anticoagulant activity, and are referred to as low molecular weight heparins. They are used mainly in the prophylaxis of venous thrombo-embolism, as they have a longer
action than standard heparin. They are given by once-daily s.c. injection, and laboratory control of the bleeding time is not necessary. The dose varies to some extent with the product used.
hepatitis A & 8 vaccines Inactivated hepatitis virus antigens for the protection of individuals highly exposed to the infections. Dose: see data sheets. (I iaverix A;
kncigix B; II–B–Vax).
theroin See diamorphine.
hetastarch A soluble modified starch that is used as a 6% solution with 0.9% sodium chloride as a plasma volume expander. Dose: 500-1500 nil daily by i.v. infusion, up to a maximum of 20 mltkg daily. It is excreted by the kidneys, and care must be taken to avoid circulatory overload. Not for use in congestive heart failure or renal insufficiency. Side-effects are vomiting, chills, fever and urticaria. (clol-IAES; Hespan).
hexachlorophene A slow-acting antiseptic used for skin sterilization, and present in sonic medicated soaps.
hexamine (methenamine) A formaldehyde derivative of low toxicity, occasionally used as a urinary antiseptic. Dose: 2 g daily. It is usually given as hexamine hippurate to ensure the necessary acidification ol’the urine. (Iliprex).
histamine A compound present in a bound form in all mammalian tissues; its release is probably the ultimate cause of many allergic conditions.
histamine H,-receptor antagonists See antihistamines. See page 110 and Table 2.
histamine Hz -receptor antagonists Drugs that (litter from conventional antihistamines in having a selective blocking action on receptors ill the gastric cells that secrete acid. They are widely used in the treatment of peptic ulcer and other conditions requiring a reduction in gastric acid secretion. See page 162 and Table 27.
homatropine An atropine derivative with a similar but more rapid mydriatic action (15-30 minutes), but a shorter duration of effect of about 24 hours. Eye drops
(1-2%) sometimes with cocaine.
hyaluronidase A ’spreading’ factor used to increase the absorption of large-volume s.c. injections. The injection of 1500 units of hyaluronidase, either into the injection site or mixed with the injection fluid, will promote the absorption of 500-1000 mL of electrolyte solution by s.c. drip infusion. (Hyalase).
hydralazine A vasodilator that is useful in the supplementary treatment of hypertension.
Dose: 50- 100 nig daily, usually with a IlliaUide diuretic or a beta-blocking agent. Also given in hypertensive crisis by slots, i.v. injection in doses of 5-10 mg; over-rapid injection may cause a marked fall in blood pressure. Side-effects are nausea, tachycardia and fluid retention (less likely with low doses), but a lupus erythematOSLIS- like syndromemay occur with extended high-dose therapy. (Apresoline). See page 148 and “Fable 21.
hydrochlorothiazide A thiazide diuretic that brings about it marked increase in the excretion of salts and water, and is of value in congestive heart failure and other oedematous conditions. It is also of value iii as it reduces peripheral resistance, and potentiates the action of some other antihypertensive drugs.
Dose: 50-111(1 Ing daily initially in
oedenia; maintenance dose 25-50 mg daily or oil alternate days. III hypertension, 25-30 Ing daily according to need.
I lydrochlorolhiazidc, like other thiazid”, Increases the excretion of potassium as well as sodium, and in extended treatment supplementary treatment with potassium chloride or effervescent potassium tablets may be required. Side-effects include nausea, rash, dizziness and photosensitivity. (I lydroSaluric). See page 148
and ‘I able 21.
acute lyniphoblastic leukaemia and some lymphomas. In common with some other corticosteroids, hydrocortisone inhibits organ-transplant rejection and in high doses it is given to control incipient rejection.
Dose: varies considerably according to need: for replacement therapy, 20-30 mg daily: in shock, 100-300 mg or more by slow i.v. injection, repeated as required. Side-effects are numerous and include hypertension, oedema, mental disturbances, re-activation of peptic ulcer, muscle weakness and diabetes. Cushing’s syndrome may occur with high doses.
I I ydrocortisone, unlike cortisone, is active topically, in(] is used as eye drops 0.3% (usually with an antibiotic), ointment and cream (0.50/o and 11M, often with an antibiotic to control any secondary infection.
hydroflumethiazide A thiazide diuretic N,ith the actions, uses and side-effects of bendrofluazide.
Dose: 25- 100 nig daily in (lie morning; 25-50 Ing daily in hypertension.
ff lydrenox). See page 148.
hydrogen peroxide solution It contains 5-7% of H 02
, equivalent to about 20 volumes oJ oxygen. It has antiseptic and deodorizing properties, and is used mainly for cleaning wounds. It is also used as a mouthwash (diluted 1:7), and as ear drops (1:4 in water or 501% alcohol).
thydromorphone A potent opioid analgesic of the morphine type. Dose: in severe pain 1.3-2.6 Ing 4 t,-hourly. Walladone).
hydrotalcite Aluminium magnesium hydroxide carbonate. An antacid used in dyspepsia and related conditions.
Dose: I g as required.
55
hydrocortisone The principal corticosteroid, also known as cortisol, that is secreted by the adrenal cortex. It plays a major role in the metabolism of glucose, protein and calcium, in maintaining the electrolyte balance, and in reducing inflammatory and allergic responses. It is used in all cases of adrenocortical insufficiency, including Addison’s disease and after adrenalectomy. It is also used in anaphylactic shock, asthma, rheumatoid disease and allergic states. It is valuable in
hydroxocobalamin A derivative of eydnu,obdlaniin, and now the preferred form of vitamin B,, as it has a more prolonged action.
Dose: in pernicious anaemia and other vitamin 13, deficiency states, I Ing initially ian. repeated 5 times at intervals of 2-3 days; maintenance dose 1 mg by I’ll’
by )CC- Lion every 3 months. It is also given
prophylactically after total gastrectonly. (Cobalin-H; NCO-Cytalliell). See
page 112.
hydroxyapatite A natural substance with a mineral composition somewhat similar to that of bone. It is used as a source of calcium and phosphorus in osteoporosis and other deficiency states. Tablets of 830 mg are available. (Ossopan).
hypermotility of the gastrointestinal tract, and may be useful in spasmodic dysmenorrhoea.
Dose: 40-80 mg daily; in acute spasm, .10 mg by injection. (Buscopan).
hydroxychloroquine An antimalarial with the actions, uses and side-effects of chloroquine. It is also useful in rheumatoid arthritis in doses of 200-400mg daily, and in lupus erythematosus, but side-effects are numerous, and treatment requires expert supervision. (Plaquenil). See page 165.
hypromellose A cellulose-derivative that dissolves in water to form a viscid, colloidal solution. Such a solution is used as a base for eye drops to extend the action of a dissolved ophthalmic drug; to lubricate contact lenses; and to act as a lubricant in chronic, sore eye conditions.
5-hydroxytryptamine See serotonin.
hydroxurea (hydrocarbamide) A cytotoxic agent sometimes used in chronic myeloid leukaemia.
Dose: 20- 30 mg/kg as a single dose daily or 80 nig/kg every third day. Side-effects are nausea, skin reactions and myelo- suppression. (Hydrea). See page 122 and Table 8.
hydroxyzine A mild tranquillizer with some sedative and antihistaminic properties. It is given in the short-term treatment of anxiety, and in pruritus and dermatoses complicated by emotional tension. Dose: 50-400 mg daily. It has the side-effects of the antihistamines, and is not recommended where some sedation is undesirable. (Atarax; Ucerax). See page 117 and Table 3.
hyoscine (scopolamine) An alkaloid obtained from plants of the belladonna group. It is a powerful hypnotic and is widely used together with papaveretum for premedication before anaesthesia in doses of 300-600 pg by s.c. or i.m. injection. It has some antiemetic properties, and is useful in travel sickness and vertigo. Dose: 300 mg 30 minutes before starting the iourney, followed by up to 3 doses 6-hourly. Scopoderm is a patch of 500 pg. Thc side-effects of mouth dryness and dizziness are those of the anticholinergic drugs generally. It is contraindicated in glaucoma. It is used occasionally in terminal care for bowel colic and excessive respiratory secretions. Dose: 600 pg-2.4 mg daily by s.c. infusion.
hyoscine butylbromide A derivative of hyoscine that differs in lacking any central action. It is given in spasm and
I
ibuprofen A non-steroidal anti-inflammatory agent (NSAID) widely used in rheumatoid and arthritic conditions. It is also given as an analgesic for mild to moderate pain, but not for acute gout. Dose: 1.8 g daily initially; lly; maintenance duos, 600 lllg-L2 daily after food. A 5% cream is available for local use. The sideeflicts are those of the NSAID& generally. (BrUlen; Feribid). See page 165.
ichthammol A thick, dark brown liquid with a characteristic odour, derived from certain bituminous oils. It is a mild antiseptic and is used mainly in chronic eczema as a 100A, ointment or zinc paste. A solution (10% in glycerin) has been used oil ulcers and inflamed areas.
idarubicin A potent cytotoxic agent similar in actions and uses to doxorubicin. It is given orally and i.v. in acute nonlymphocytic leukaemia, breast cancer, and as second-line therapy in acute lymphatic leukaemia. Dose is based on skin area. (Zavedos). See page 122 and Table 8.
idoxuridine An antiviral agent now virtually superseded by acyclovir and related drugs. Used occasionally in herpes zoster skin infection by local application of a 5% solution. See page 144 and Table 19.
fosfamide A derivative of cyclophosphamide with similar actions and uses. It is effective in lung, ovary, breast and soft-tissue tumours, as well as some malignant lymphomas.
