Posts Tagged ‘Sidi’

Notes on dosage
In this dictionary of drugs, the doses, unless otherwise stated, are average daily doses for adults, and are normally given as divided doses at suitable intervals. An indication is given of those few drugs that are taken as a single daily dose, or where
the dose is based on the surface area of the body expressed as square metres (ml).
When a dose range is indicated, a small initial dose is often followed by gradually increasing doses according to need and response, but with long-acting drugs care must be taken to avoid excessive dosage, as such drugs may then accumulate in the body and have toxic side-effects. It should be noted that the side-effects of a drug may prevent the administration of an optimum therapeutic dose, and a recommended dose is often a compromise between activity and toxicity. The gap is sometimes referred to as the ‘therapeutic window’, and the wider the gap the safer the drug.
Dosage is also influenced by the route of administration, as oral doses are normally larger than those given by intramuscular injection, and the latter are in turn larger than those given intravenously. The weight, age and sex of a patient may also have to be taken into account when assessing dosage. Renal and hepatic
-impairment may require an adjustment of dose, whereas if tolerance to a drug
develops, a larger dose may be required to evoke an adequate response. Dosage
also requires particular care during pregnancy if toxic effects on the fetus are to be avoided and, ideally, no drug should be given in pregnancy unless the need outweighs the risks.
Doses for infants also present problems. Their drug-detoxifying enzyme
systems and renal excretory capabilities are not fully developed although,
paradoxically, they have higher metabolic rates than adults, and so may sometimes require an apparently relatively high dose of a drug.

Doses for the elderly also frequently require modification, as their reduced renal efficiency may cause accumulation of the drug and increase susceptibility to toxic effects, unless reduced doses are given. Elderly patients are, in any case, more susceptible to nephrotic drugs generally. Hepatic disease may also increase drug toxicity as liver enzymes play a major part in drug metabolism, and severe liver disease may give rise to a drug toxicity that might not otherwise occur. Hyperlipidaemic drugs, fusidic acid and some antifungal agents of the ketoconazole type are examples of drugs best avoided in hepatic disease. Multiple therapy may also lead to an increased and not always appreciated incidence of drug toxicity. For further information on these important aspects of drug dosage, a book for nurses on drugs and pharmacology should be consulted.

Controlled drugs
Drugs likely to cause dependence and misuse are referred to as ‘controlled drugs’ (CDs), as they are subject to the strict prescription requirements of the Misuse of Drugs Act, 1971, and are distinguished in this book by a dagger t. They include opium, morphine, heroin (diamorphine), pethidine and other synthetic, potent analgesics/narcotics, dihydrocodeine injection, barbiturates (except intravenous anaesthetics) and amphetamines. Controlled drugs can be supplied only on receipt of a hand-written prescription from the prescriber, giving full details of the patient, the drug, the form and strength of the prescription to be dispensed, and the total amount to be supplied expressed in both words and figures. Certain weak preparations of some controlled drugs, such as Kaolin and Morphine Mixture for diarrhoea, with which misuse is unlikely, are exempt from control, and can be obtained without prescription.

gelatin A protein obtained by the hydrolysis of animal tissues. Used orally as nutrient jellies, and specially refined solutions have been used as blood volume expanders (see dextran). (Gelofusine; Haemaccel).
I Gil
nephrotoxic side-effects, and dosage requires care when renal function is inadequate, and also in elderly patients. Gentarnicin is also used locally as cream or ointment (0.3%) and as eye drops (0.3%). (Cidomicin; Genticin).
gemcitabineV A cytotoxic agent related
to cytarabine, but with increased
potency and a longer action. It blocks cancer cell replication by inhibiting DNA synthesis, and may enhance the action of other agents. It is used mainly in the palliative treatment of non-small cell lung cancer.
Dose: 1000 mg/m-’ by slow i.v. infusion over 30 minutes, once a week for 3 weeks, repeated after a rest period. It is generally well tolerated, but a common side-effect is a transient influenza-like reaction. Myelosuppression is less severe than that of related cytotoxic agents. (Gemzar). See page 122 all(] Table 8.
gentian violet See crystal violet.
gestrinone An antiprogestogen used in ctidonictriosis that acts indirectly by suppressing gonadotrophin production. Dose: 2.5 ing twice weekly oil the same day,, each week for o months. Side-effects arc fluid retention, acne and voice changes. ( Dimetriose).
gestronel A synthetic progestogen used in the treatment of breast and endonietrial carcinoma and benign prostatic hypertrophy.
Dose: 200-400 ing i.m. once a week. (Depostat).
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gemeprost A synthetic prostaglandin used to dilate the cervix uteri in first trimester abortion.
Dose: I mg, as a pessary 3 hours before surgery. Side-effects are mild uterine pain and vaginal bleeding initially, nausea and di.11 I hoc.).
gernfibrozil A plasma lipid regulating agent, with the actions and uses of hez.afibrate and clofibrate.
Dose: 901) ing-1.3 mg daily, with regular checks oil plasma lipid levels. Treatment should be withdrawn after 3 months if the response is unsatisfactory. Gernfibrozil may potentiate the action of oral anticoagulants, the dose of which should be adjusted. Side-effects include nausea, diarrhoea, abdominal pain, rash and dizziness. (Lopid). See page 146 and Table 20.
gentamicin An aminoglycoside antibiotic, active against a wide range of Gram-negative organisms, including Pseudomonas aeruginiosa, as well as against many Gram-positive bacteria, although it is not very active against anaerobic organisms. It is of great value in septicaemia and meningitis, as well as in bacterial endocarditis.
Dose: 2-3 nig/kg daily by i.m. injection or i.v. infusion. In serious or undiagnosed infections, supplementary treatment with a penicillin or metronidazole may be require(]. In common with other arninoglycosides, goitarnicin has ototoxic and
glibenclarnide An orally active hypoglycaenfic agent similar to chlorpropamide. Dose: 5-15 nig daily, according to need and response. (Daonil; Euglucon). See
page 131 and’I'able 13.
gliciazide A sulphonylurea with the actions and uses of chlorpropamide and related drugs.
Dose: 40-320 mg orally. (Diarnicron). See page 131 and Table 13.
glimepiride A sulphonylurea used in non-ill Sidi 11 -dependent (Type 11) diabetes mellitus.
Dose: 2 mg after breakfast, increased ill, to .1 mg daily. Side-effects include
transient visual disturbances, rash and urticaria. (Amaryl). See page 131 and Table 13.
glipizide A sulphonylurea, used like chlorpropamide in diabetes, but effective in much lower doses.
Dose: 5 mg initially, maintenance dose 2.5-40 nig daily. (Glibenese; Minodiab). See page 131 and Table 13.
gliquidone An oral hypoglycaemic agent similar to chlorpropamide. Effective in maturity-onset diabetes.
Dose: I5 ing initially; maintenance dose 40-60 nig daily, but up to 180 mg daily have been given. (Glurenorni). See page 131 and Table 13.

glucagon A hormone of the alpha cells of the pancreas which raises the blood sugar level by mobilizing liver glycogen. Used in acute hypoglycaemia.
Dose: 0.5-1 mg by s.c., i.m. or i.v. iniection. (GlucaGen). Give i.v. glucose if there is no response within 10 minutes.
glucocorticoids Those corticostcroids with an anti-inflammatory action similar to hydrocortisone, as distinct from the mmerailocorticoids, such as fludrocortisone, used in Addison’s disease. Thel, differ in anti-inflammatory potency, and 0.75 mg of dexamethasone is considered equivalent to 20 mg of hydrocortisone. See Table 36.
glucose Also known as dextrose. A readily absorbed carbohydrate present in many
man
sweet fruits, but obtained commercially by the hydrolysis of starch. It is given orally as a dietary supplement; in acidosis; and to raise the glycogen reserves of the liver in hepatic damage. Given by i.v. infusion as a 5% solution, or as a glucose-saline infusion in dehydration and shock, and after surgery until fluids call be taken by mouth.
glutaraldehyde A disinfectant of the formaldehyde type, but with a more rapid and powerful action. Effective against a wide range of organisms, including
viruses. Used mainly for instrument sterilization as a 2% solution. Usually activated before use by the addition of a corrosion inhibitor. Such activated solutions are stable for about 2 weeks. It is also used as a 10% solution for the removal of plantar warts.
glycerin (glycerol) A clear syrupy liquid used as a sweetening agent in mixtures and linctuses. It promotes drainage when applied to inflamed areas, and is used as a paste with magnesium sulphate for boils. It is also used as suppositories for constipation.
Dose: sometimes given orally in doses of ]- 1.5 g/kg in glaucoma and before surgery to lower the intraocular pressure.
glyceryl trinitrate A powerful but short-acting vasodilator used in the control of angina pectoris. See page 114.
Dose: 300, 500 or 600 pg tablets which should be dissolved under the tongue for a rapid response. An aerosol spray (400g per
dose), as well as long-acting tablets are also available. Tolerance may occur with prolonged therapy. Side-effects are a throbbing headache, flushing and tachycardia. It is also used locally for all extended action, particularly at night, as ointment and medicated patches. Also given by i.v. infusion to control hypertension and ischaemia during cardiovascular surgery and in left ventricular failure. Dose: 10-200 pg/min in dextrose-saline. A new use of the drug is as an ointment (0.2%) to promote healing of anal Fissure. See page 1] 4 and Table 4.
glycopyrronium A synthetic atropine-like antispasmodic used for preoperative medication.
Dose: 200-400 pg by Lill. or i.v. injection. I i has the side-effects of anticholinergic drugs such as dryness of the mouth and blurred vision. Contraindicated in glaucoma. (Robinul).
GM-CSF Granulocyte-macrophage colony stimulating factor. See molgramostim. gold therapy See sodium aurothionialate.
gonadotrophins The follicle-stimulating hormone (FSH) and the luteinizing hormone (1-11) of the anterior pituitary gland. They stimulate ovarian development and the production of oestrogens; ill the male LH controls the formation of androgens. See gonadorclin.
gonadorefin A synthetic form of the gonadot roph in -releasing hormone of the pituitary gland (M-111-1). It is used to assess pituitary function.
Dose: 100 pg by i.v. injection normally
rise to a rapid rise in the plasma level of the luteinizingand follicle-stimulating hormones. In amenorrhoea and infertility due to gonadorelin insufficiency, it is given by pulsed s.c. infusion in doses of 1-20pg every 90 minutes, day and night. Treatment for up to 6 months may be required. Side-effects are uncommon. (Fertiloli Relefact). Sonic analogues of gonadorelin are used in remain cancers. See page 122.
goserelin A synthetic analogue of the hypothalamic hormone (LH-RH). It
suppresses the production of testosterone, d
anis used in the treatment of hormone-
dependent carcinoma of the prostate. It is also used in endometriosis and postmenopausal breast cancer.

Dose: 3.6 ing by s.c. injection every 28 days or as an implant. Side-effects include impotence, hot flushes, rash, breast swelling and tenderness. (Zoladex). See page 122 and ‘I able 8.
gramicidin A mixture of antibiotics effective against many Gram-positive organisms, but it is too toxic for syitenii, use. Used topically in infected skin conditions, usually in association with neomycin and hydrocortisone.
granisetron A scrotonin (5—HT) antagonist with a highly selective and powerful antiernetic action mediated by its effects on the 5-4-11′, receptors. It is used in the prevention and treatment of the severe nausea and vomiting induced by potent cytotoxic drugs such as cisplatin.
Dose: I mg I hour before treatment, then I ing twice daily, or by i.v. infusion in doses of 3 mg, repeated up to 3 times over 24 hours. For prophylaxis, a dose of 3 mg should be given before chemotherapy is commenced. Headache, rash and consti pation are common side-effects. (Kytril). See page 158.
griseofulvin An orally effective but slow
acting antifungal antibiotic that is
deposited selectively in the skin, hair and nails. It is used in the systemic treatment of ringworm and other dermatophyte infections of the keratin-containing tissues, but only when local treatment has failed.
Dose: 0.5-1 g daily, but prolonged therapy is required. Side-effects are headache, nausea, dizziness, rash and photosensitivity. 11 may also reduce the effects of oral contraceptives. (Fulcin; Grisovin).
growth hormone See soma(ropin.
guanethidine An anti-hypertensive drug that [)rings about a reduction in blood pressure by blocking transmission in adrenergic nerves, and preventing the release of noradrenaline. It has been used in the treatment of hypertension, often with a thiazide diuretic, but its use has declined as it may cause postural hypotension. Still used as part of combined therapy in resistant hypertension.
Dose: 20 mg daily, increased by 10 ing at weekly intervals according to response, up to 50 mg daily, although sometimes larger doses are required. Dose by i.m. injection,
10-20 nig as required. Diarrhoea, weakness, nasal congestion and bradycardia are common side-effects. (Ismelin). See page 148 and Table 21. Guanethidine is occasionally used as eye drops (1-3%) in glaucoma. (Ganda). See page 138 and Table 16.
guar gum A vegetable gum that, when taken with food, appears to retard the absorption of carbohydrates. It is used in the supplementary treatment of diabetes mellitus.
Dose: up to 15 g daily, usually sprinkled mi food. It is essential that a dose should he taken with an adequate fluid intake, and that the final dose is not taken at bedtime. Side-effects are flatulence and abdominal distension. (Guarem). See page 131 and Table 13.
halcinonide A powerful corticosteroid used iii severe inflammatory skin conditions not responding to other corticosteroids. It is applied sparingly as a 0.1% cream. (Halciderin).
halibut-liver oil A rich source of vitamins A ‘Ind 1).
Dose: 0.2-0.5 mi.
halofantrine An antimalarial, acting at the erythrocytic stage of the life cycle of plasmodium, and useful in chloroquine 01 MUlti-drug resistant malaria.
Dose: 500 nig 6-hourly for 3 doses between meals. Side-effects are nausea, vomiting and diarrhoea. It must not be given with or after mefloquine (risks of fatal arrhythmias). Contraindicated in pregnancy. 0 lalfan).
haloperidol A powerful tranquillizer used in schizophrenia, mania and psychoses. Dose: 5-20 ing daily, up to a maximum of 200 mg, reduced later according to
response. Dose by i.m. injection for rapid control of hyperactive psychotic patients, 5-30 mg initially, followed by 5 ing or more as required. For depot treatment, it is given as haloperidol decanoate, 50-300 mg by deep i.m. injection every 4 weeks. It is also given orally in doses of 500 g twice daily in severe anxiety. Doses of 1.5 nig