An overview of therapeutic interventions in myocardial infarction. Emphasis on secondary prevention.

The high risk of subsequent mortality and morbidity following the occurrence of a myocardial infarction (MI) underlies the importance of instituting effective preventive regimens as part of the overall management of these patients. The aim of such treatment is to prolong survival by preventing sudden and non-sudden death and further major cardiovascular events. Currently available data from randomised, controlled clinical trials in MI patients indicate that early treatment with thrombolytic agents [streptokinase, anisolyated plasminogen streptokinase activator complex (APSAC) or recombinant tissue-type plasminogen activator (rt-PA)] in the first few hours after onset of symptoms significantly reduces the short term mortality following MI, with follow-up studies at 1 year indicating that the early benefits persist long term. The optimum time for initiation of thrombolytic therapy is within 6 hours of onset, but treatment started between 7 and 24 hours after onset can also be beneficial. Similarly, there is good evidence that beta-blockers (e.g. propranolol, timolol, metoprolol, atenolol) and aspirin are effective in reducing both the mortality and reinfarction rate following MI. With beta-blockers, a policy of starting treatment early intravenously and continuing orally for 2 to 3 years seems likely to save more lives than either strategy alone; however, contraindications to beta-blockade reduce the number of patients eligible to receive this treatment. In the case of aspirin, the optimum dosage has yet to be determined, but on the basis of present evidence, it seems reasonable to start treatment early with doses of 160 to 325 mg daily and continue for a year or 2 after recovery. Other studies have shown that long term oral anticoagulant therapy is also effective in reducing the mortality and reinfarction rate after MI. Subcutaneous heparin therapy given for 10 days in patients with acute anterior MI reduces the frequency of left ventricular mural thrombosis, while intravenous heparin given for greater than or equal to 4 days improves coronary artery patency rates following administration of a thrombolytic agent. In a comparison with low dose aspirin, intravenous heparin proved more effective in maintaining coronary artery patency rates after rt-PA thrombolysis. There is also evidence that oral nitrates may reduce mortality in MI patients, especially in those with heart failure. However, current data on the use of antiarrhythmic drugs do not support the routine of these drugs following MI. Similarly, with lipid-lowering agents, the evidence that lowering cholesterol is beneficial in reducing mortality after MI is at present inconclusive. Further studies with these groups of drugs are awaited with interest.(ABSTRACT TRUNCATED AT 400 WORDS)

Minocycline: A review of its antibacterial and pharmacokinetic properties and therapeutic use.

Minocycline is a semi-synthetic tetracycline derivative which is well absorbed and distributed in body tissues and is suitable for twice daily administration. It appears to be as generally effective as other tetracyclines and analogues, but also to be effective in infections due to tetracycline-resistant staphylococci. Side-effects are typical of those of other tetracyclines, but minocycline has been associated with a high incidence of vertigo in some studies. On the other hand, minocycline appears to have little or no photosensitising potential. It is not yet clear whether minocycline can be safely used in patients with moderate or severe impairment of renal function, but if used in renal failure, the plasma urea concentration should be monitored.

Timolol: a preliminary report of its pharmacological properties and therapeutic efficacy in angina and hypertension.

Timolol (MK 950) is a new beta-adrenergic receptor blocking drug. It has little or no membrane stabilising ('quinidine-like') or partial agonist (intrinsic sympathomimetic) activity and thus resembles sotalol. On a weight for.weight basis, timolol is more potent than sotalol or propranolol. A 2.5 mg dose of timolol causes about the same reduction in resting heart rate as 20mg of propranolol. Results of placebo-controlled and of comparative trials with other beta-adrenergic receptor blocking drugs, have shown that timolol effectively lowers blood pressure without producing orthostatic or exercise hypotension. Findings of an international multicentre trial in angina pectoris, indicate that timolol is effective in reducing the frequency of anginal attacks and the consumption of glyceryl trinitrate for their relief.

Bumetanide: A preliminary report of its pharmacological properties and therapeutic efficacy in oedema.

Bumetanide2 is a new diuretic with a rapid onset and short duration of action. It is advocated for the treatment of oedema of cardiac origin; that associated with cirrhosis of the liver and renal diseases, including the nephrotic syndrome oedema of pregnancy and in pulmonary oedema. Bumetanide produces a pattern of water and electrolyte excretion closely resembling that of frusemide although it differs structurally from frusemide and other diuretics. 1 mg of bumetanide produces a diuretic effect similar to that evoked by 40 to 60 mg of frusemide. Short-and long-term studies in oedema of varying aetiology have shown bumetanide to be an effective diuretic. Because it is chemically different from existing diuretics, bumetanide may be helpful in oedema resistant to other drugs. It is well tolerated, but like other natriuretics it causes hypericaemia and may cause hypokalaemia during long-term administration.

Amoxycillin: A review of its antibacterial and pharmacokinietic properties and therapeutic use.

Amoxycillin2 is an acid stable semisynthetic penicillin closely related to ampicillin. Unlike pivampicillin and hetacillin, amoxycillin is not converted to ampicillin in the body. The antibacterial spectrum and level of activity of amoxycillin is essentially the same as for ampicillin, and there is complete cross-resistance between the two drugs. After oral administration, amoxycillin is better absorbed than ampicillin. Mean peak serum levels of amoxycillin are generally twice those of ampicillin after an equal dose. The better absorption and penetration into certain body tissues and fluids of amoxycillin and its greater activity against experimental infections in mice, suggest that it might be preferred to ampicillin in the treatment of some infections, but any clear superiority over ampicillin in clinical practice has yet to be demonstrated. However, these properties have enabled amoxycillin to be given at half the dose of ampicillin without loss of therapeutic efficacy, and the princpal side-effects of skin rashes and diarrhoea have tended to be less frequent with amoxycillin than with ampicillin. Other side-effects are essentially similar in nature to those reported with ampicillin.

Etretinate. A review of its pharmacological properties and therapeutic efficacy in psoriasis and other skin disorders.

Etretinate (Ro 10-9359) is a new aromatic retinoic acid derivative for the treatment of severe psoriasis and other dyskeratoses. The pharmacological profile of etretinate suggests that it acts by normalizing pathological changes in epidermal and dermal skin, particularly inhibiting hyperkeratinization and cell differentiation, although its specific mode of action in different disorders remains to be elucidated. Etretinate is rapidly and presystemically metabolised to an active metabolite which appears in plasma at about the same time as parent drug. A 'deep' storage compartment with a very extended elimination half-life gives rise to detectable plasma levels of drug for at least 3 to 4 months after discontinuation of long term therapy. Studies suggest that etretinate at an initial dose of 1 mg/kg/day, reducible during maintenance therapy, is an effective alternative to PUVA and other conventional therapy in severe psoriasis. Its greatest immediate value is in the control of eruptive and treatment-resistant psoriasis, and in its potential for use in combination with other therapy to improve the response. In Darier's disease it appears to be the treatment of choice, and preliminary studies also suggest its usefulness in ichthyosis, and most other dyskeratoses and possibly in basal cell carcinoma. Side effects affecting the mucocutaneous system occur in nearly all patients, but rarely lead to drug withdrawal. When withdrawal does become necessary, the primary reason is usually hair loss. A few paradoxical observations of raised and lowered liver enzyme levels have been reported, and also a few cases of suspected liver damage. Etretinate is strictly contraindicated in women of child-bearing potential due to its severe teratogenic properties.

Cefotaxime. A review of its antibacterial activity, pharmacological properties and therapeutic use.

SYNOPSIS: Cefotaxime is a new 'third generation' semisynthetic cephalosporin administered intravenously or intramuscularly. It has a broad spectrum of activity against Gram-positive and Gram-negative aerobic and anaerobic bacteria, and is generally more active against Gram-negative bacteria than the 'first' and 'second generation' cephalosporins. Although cefotaxime has some activity against Pseudomonas aeruginosa, on the basis of present evidence it cannot be recommended as sole antibiotic therapy for pseudomonal infections. However, cefotaxime has been effective in treating infections due to other 'difficult' organisms, such as multidrug-resistant Enterobacteriaceae. Like other cephalosporins, cefotaxime is effective in treating patients with complicated urinary tract and lower respiratory tract infections, particularly pneumonia caused by Gram-negative bacilli. High response rates have also been achieved in patients with Gram-negative bacteraemia. Although favourable clinical results have been obtained in patients with infections caused by mixed aerobic/anaerobic organisms (such as peritonitis or soft tissue infections), the relatively low in vitro activity of cefotaxime against Bacteroides fragilis may restrict its usage in situations where this organism is the suspected or proven pathogen. In preliminary studies, males and females treated with a single intramuscular dose of cefotaxime for uncomplicated gonorrhoea caused by penicillinase-producing strains of Neisseria gonorrhoeae responded very favourably. Encouraging results have also been reported in open studies in children including neonates, treated with cefotaxime for meningitis and various other serious infections. In some situations, cefotaxime has been given in combination with another antibiotic such as an aminoglycoside, but the merits of such a combination have not been clearly established. Whether cefotaxime alone is appropriate therapy for conditions previously treated with aminoglycosides (other than pseudomonal infections) also needs additional clarification, but if established as equally effective in such conditions cefotaxime offers potentially important clinical and practical advantages in its apparent lack of serious adverse effects and freedom from the need to undertake drug plasma concentration monitoring.

Captopril: an update review of its pharmacological properties and therapeutic efficacy in congestive heart failure.

Captopril is the first angiotensin-converting enzyme inhibitor for oral administration. In combination with continued digitalis and diuretic therapy it has been demonstrated to be effective in the management of severe heart failure refractory to optimal digitalis, diuretic and, in many patients, vasodilator treatment. Most studies to date have been open trials of several weeks or months duration, but a number of patients have received continued treatment, with sustained benefit, for up to 1 year or more. A placebo-controlled trial in a limited number of patients with less severe heart failure has confirmed the results of open trials. Captopril administration improves cardiac performance as a result of a reduction in systemic vascular resistance (afterload) and the various determinants of left ventricular filling pressure (preload). Improvements in exercise tolerance and functional classification, with associated reduction of clinical symptomatology, occur with simultaneous decreases in myocardial oxygen consumption. At present, captopril is worthy of a trial in patients refractory to more traditional medical management. Whether it should be considered a 'first-line' agent after failure of optimal digitalis and diuretic therapy, and before instituting other vasodilator therapy, is less clear. In patients with severe or resistant heart failure, a response to captopril is usually accompanied by a general improvement in the quality of life. The effect of captopril treatment on 1- and 2-year survival rates in patients with severe heart failure appears similar to that reported for other vasodilators. Most patients tolerate captopril treatment well, but hypotension, reduced renal function, skin rash, dysgeusia, and neutropenia have been reported.

Auranofin. A preliminary review of its pharmacological properties and therapeutic use in rheumatoid arthritis.

Auranofin is the first orally active gold compound for the treatment of rheumatoid arthritis. Like other chrysotherapeutic agents, its exact mechanism of action is unknown, but it probably acts via immunological mechanisms and alteration of lysosomal enzyme activity. Although long term clinical experience with auranofin is limited, its efficacy appears to approach that of sodium aurothiomalate. Further comparative studies with aurothioglucose, hydroxychloroquine and D-penicillamine are required before definitive statements can be made regarding the relative efficacy of auranofin and these agents. While patients have demonstrated clinical remission of rheumatoid arthritis in response to auranofin therapy, radiological studies have been inconclusive regarding its effect on the occurrence or progression of erosive lesions. Auranofin is relatively well tolerated in most patients, but diarrhoea, skin rash, and pruritus are sometimes troublesome, and thrombocytopenia and proteinuria are potentially serious side effects which may occur during therapy. Whereas mucocutaneous side effects are more frequent with injectable gold compounds, gastrointestinal reactions are the most common adverse effect seen with auranofin. The frequency of side effects has been similar with auranofin and sodium aurothiomalate, but they are generally less severe with auranofin. While some of the side effects are controlled by a reduction in dosage, temporary or permanent withdrawal of auranofin may be necessary. Auranofin is clearly a useful addition to the limited list of agents with disease-modifying potential presently available for the treatment of rheumatoid arthritis. It will doubtless generate much interest as its final place in therapy becomes better defined through additional well-designed studies and wider clinical experience.

Ursodeoxycholic acid: a review of its pharmacological properties and therapeutic efficacy.

Ursodeoxycholic acid is the 7 beta-hydroxy epimer of chenodeoxycholic acid and is normally present in only trace amounts in the bile. Oral administration of pharmacological doses markedly decreases biliary cholesterol saturation. Complete or partial dissolution of radiolucent gallstones located in a functioning gallbladder occurred in about 40 to 55% of patients treated with ursodeoxycholic acid in controlled studies of 6 months duration. Patients showing partial gallstone dissolution at that time are likely to continue improving possibly to complete gallstone dissolution with continued therapy. The success rate with ursodeoxycholic acid may be increased top about 80% if more stringent patient selection criteria are applied to include only those with non-calcified floating cholesterol stones of less than 10 to 15 mm diameter. Those with calcified stones or stones greater than 15 mm diameter or unlikely to respond to ursodeoxycholic acid therapy. The optimal dose in published studies was about 8 to 10 mg/kg/day, which is about half to two-thirds the dose of chenodeoxycholic acid (15 mg/kg/day) achieving approximately equivalent results. Ursodeoxycholic acid appears to be remarkably well tolerated, with diarrhoea occurring in only a very small proportion of patients. While surgery is clearly the preferred treatment in many patients with symptomatic gallstones, in a carefully selected subgroup of such patients gallstone dissolution therapy with ursodeoxycholic acid offers an important and worthwhile alternative.

Indapamide. A review of its pharmacodynamic properties and therapeutic efficacy in hypertension.

Indapamide is an orally active sulphonamide diuretic agent. Although some evidence appears to indicate that the antihypertensive action of indapamide is primarily a result of its diuretic activity, only a limited diuresis occurs with the usual antihypertensive doses of 2.5 mg daily, and in vitro and in vivo data suggest that it may also reduce blood pressure by decreasing vascular reactivity and peripheral vascular resistance. In mild to moderate hypertension it is as effective as thiazide diuretics and beta-adrenergic blocking agents in lowering blood pressure when used as the sole treatment. Indapamide has been successfully combined with beta-adrenergic blocking agents, methyldopa, and other anti-hypertensive agents. While such findings need confirmation, it appears that indapamide shares the potential with other diuretic agents to induce electrolyte and other metabolic abnormalities, although it may do so with less frequency or severity. Thus, indapamide appears to offer a suitable alternative to more established drugs as a 'first-line' treatment in patients with mild to moderate hypertension. Whether it differs significantly from other diuretics when used as antihypertensive therapy, either in its mode of action or its side effect profile, needs further clarification.

Trifluridine: a review of its antiviral activity and therapeutic use in the topical treatment of viral eye infections.

Trifluridine (trifluorothymidine) is an antiviral agent for topical use in the eye, and is structurally related to idoxuridine. In vitro studies have shown that it effectively inhibits the replication of herpes simplex virus type 1, which causes primary keratoconjunctivitis and recurrent epithelial keratitis in man. In masked comparative studies, predominantly in patients with dendritic ulcers, trifluridine 1% solution was effective in over 90% of patients; in such studies it was comparable with vidarabine in treating dendritic ulcers, and was at least as effective as, and in some studies more effective than, idoxuridine. The drug was also effective in treating a small number of patients with geographic ulcers (sometimes associated with the usage of topical corticosteroids), and this could be an important advantage if confirmed in further well-designed studies. However, experience at present is too limited to reliably determine the usual response rate in this difficult therapeutic area. In open studies the drug proved to be particularly useful in treating ulcers previously unresponsive to idoxuridine or vidarabine, and in treating patients intolerant of idoxuridine, with a high success rate and minimal side effects being reported. The role of trifluridine in treating deep stromal disease, uveitis, or adenovirus kerato-conjunctivitis has not been established. The drug is well tolerated and cross-hypersensitivity and cross-toxicity between trifluridine, idoxuridine and vidarabine are rare. Thus, trifluridine is an effective alternative to the drugs available for treating herpetic keratitis, and seems especially useful in 'difficult' cases.

Ranitidine: a review of its pharmacology and therapeutic use in peptic ulcer disease and other allied diseases.

Ranitidine is a new histamine H2-receptor antagonist which, unlike cimetidine, does not contain an imidazole group. On a weight basis, ranitidine is 4 to 10 times more potent than cimetidine in inhibiting stimulated gastric acid secretion in humans. Therapeutic trials comparing ranitidine and cimetidine have demonstrated that ranitidine 150 mg twice daily is an effective alternative to cimetidine 1000 mg daily in 4 divided doses in increasing the rate of healing of duodenal and gastric ulcers over a period of 4 to 6 weeks. Ranitidine, given as a single 150 mg dose at night, decreases the incidence of ulcer recurrence. Preliminary studies in the Zollinger-Ellison syndrome and in patients intolerant of, or unresponsive to cimetidine, indicate that ranitidine controls the gastric hyperacidity and heals most ulcers, including those which failed to respond to months of treatment with cimetidine 1 to 1.6 g daily. Ranitidine, unlike cimetidine, has no antiandrogenic effects and does not alter hepatic metabolism of drugs. Ranitidine is well tolerated. Preliminary reports of the resolution of cimetidine-induced adverse effects following substitution of ranitidine, suggest that ranitidine may be of value in patients intolerant of cimetidine. However, wider clinical experience with ranitidine is needed to determine the clinical relevance of these reports.

Piroxicam: a review of its pharmacological properties and therapeutic efficacy.

Piroxicam is an N-heterocyclic carboxamide of 1,2 benzothiazine 1,1 dioxide with analgesic and anti-inflammatory activity. It has an extended half-life of about 40 hours and is suitable for once daily administration. Published studies indicate that piroxicam 20mg daily is comparable with aspirin 3 to 6g. indomethacin 75 to 150mg, phenylbutazone 400mg, naproxen 500mg, ibuprofen 1200 to 2400mg and diclofenac 75mg in rheumatoid arthritis. In osteoarthritis, piroxicam 20mg daily is comparable in efficacy with aspirin 2.6 to 3.9g, indomethacin 75mg, naproxen 500mg and fenbufen 600mg but is generally better tolerated than aspirin or indomethacin in patients with arthritic diseases. Piroxicam 20mg was at least as effective as indomethacin 75mg in a study in ankylosing spondylitis. As with other non-steroidal anti-inflammatory drugs gastrointestinal complaints are the most frequently reported side effects and their frequency and severity appears to be dose-related.

Trazodone: a review of its pharmacological properties and therapeutic use in depression and anxiety.

Trazodone is a triazolopyridine derivative with antidepressant activity, that is chemically unrelated to other currently available antidepressants. Its pharmacological properties differ from those of most other antidepressants. Trazodone exhibits antiserotonin activity in animal studies, but its mechanism of action in depressive illness in humans is not clear. It has an overall therapeutic efficacy comparable with imipramine and amitriptyline in depressive illness but, at dosages which have achieved a similar overall clinical improvement, trazodone causes fewer anticholinergic side effects than the tricyclic antidepressants. Trazodone appears also to have activity against the concomitant anxiety in depressed patients and in limited studies was comparable with diazepam and chlordiazepoxide in anxiety neurosis. Trazodone has been reported to be of value in tremors and chronic alcoholism. Studies in animals, limited human studies and the low incidence of cardiovascular side effects in controlled therapeutic trials, suggest that trazodone is less likely than imipramine to cause cardiotoxicity at therapeutic doses, but the effects of overdosage are not known at present. Trazodone appears to be well tolerated by the elderly, seldom aggravates psychotic symptoms and does not produce neurological side effects.

Fenbufen: a review of its pharmacological properties and therapeutic use in rheumatic diseases and acute pain.

Fenbufen is a phenylalkanoic acid derivative with analgesic and anti-inflammatory activity. The anti-inflammatory activity appears to reside in the metabolites. Published data indicate that fenbufen 600 to 1000mg daily is comparable in effectiveness to therapeutic doses (3 to 4g) of aspirin, indomethacin (75 to 100mg) or phenylbutazone (300 to 400mg) in rheumatoid arthritis, but generally causes fewer side effects. At a daily dosage of 600mg, fenbufen is comparable with aspirin 3.6g or indomethacin 75mg in osteoarthritis. Initial studies suggest that fenbufen 600 to 900mg daily is at least as effective as ibuprofen 1200 to 1800mg of fenoprofen 1800 to 2400mg daily. It has not been compared with naproxen or sulindac in adequate numbers of patients. Fenbufen is effective when given twice daily and there is some evidence that once daily dosage is adequate in known responders to the drug. As with other non-steroidal alkanoic acid drugs, gastrointestinal complaints are the most frequently reported side effects, but there have been no reports of peptic ulcer to date.

alpha-Methyl-p-tyrosine: a review of its pharmacology and clinical use.

alpha-Methyl-p-tyrosine is an orally active inhibitor of catecholamine synthesis which inhibits the hydroxylation of tyrosine to dopa. At dosages of 600 to 3500 mg daily it is effective in controlling the hypertensive episodes and symptoms of catecholamine excess in phaeochromocytoma during preparation for surgery. Limited published experience suggests that it is effective in controlling hypertension and symptoms in malignant phaeochromocytoma, but further long term experience is needed. Concomitant administration of phenoxybenzamine and propranolol may be desirable in some patients and treatment with phentolamine is usually necessary to control hypertension during manipulation of the tumour.

Penbutolol: a preliminary review of its pharmacological properties and therapeutic efficacy in hypertension and angina pectoris.

Penbutolol is a non-selective beta-blocking drug with 'moderate' intrinsic sympathomimetic (partial agonist) properties, and a relatively narrow dose-response range. In many other aspects its pharmacological profile resembles that of propranolol. Significant beta-blockade, as demonstrated by reduction in heart rate during exercise in healthy subjects, persists for at least 24 hours after penbutolol administration, and thus the recommended dosage schedule in both hypertension and angina involves single daily doses (20 or 40mg daily) in most patients, with a divided dose (40mg twice daily) if a higher dose is needed. However, most angina prophylaxis studies to date have not been designed to clearly demonstrate that the beneficial effects of beta-blockade with a single dose of penbutolol extend throughout a 24-hour dosing interval. Further studies are needed to provide such evidence. As might be expected, penbutolol appears to be about as effective as usual doses of propranolol in both mild to moderate hypertension and in angina, but much of the clinical experience with the drug is in unpublished form and is thus somewhat difficult to evaluate in detail. The choice of a beta-blocking drug should be based on a knowledge of the characteristic pharmacodynamic and pharmacokinetic properties of the individual drugs within this group, and on careful consideration of how these properties might be used to benefit the individual patient. As is the case with most other beta-blocking drugs, penbutolol has some specific properties (e.g. relatively narrow dose-response range minimising the difficulty of dose titration, moderate intrinsic sympathomimetic activity) which may be used to advantage in certain patients.

Gliclazide. A preliminary review of its pharmacodynamic properties and therapeutic efficacy in diabetes mellitus.

Gliclazide is a 'second generation' oral hypoglycaemic agent. The particular interest with this drug is that it has shown certain effects on the blood for which it is hoped there may be some clinical benefit in diabetic angiopathies. Both in animal and human studies it has demonstrated a reduction in platelet adhesiveness and aggregation, whilst possible enhancement of platelet metabolism, reduction of coagulant factors, as well as increased fibrinolytic activity, are still being investigated. Initial trials have suggested that gliclazide therapy may reverse or at least slow down the progression of diabetic retinopathy. However, a few additional well-designed long term controlled studies are needed to confirm these findings, and to clarify whether any beneficial effect on diabetic retinopathy is unique to gliclazide or also occurs with other oral hypoglycaemic drugs. Both newly diagnosed maturity onset diabetics as well as those previously treated with sulphonylureas respond well to gliclazide therapy. In the small comparative studies which have been reported, gliclazide was of comparable efficacy to other oral hypoglycaemic agents.

Sucralfate. A review of its pharmacodynamic properties and therapeutic use in peptic ulcer disease.

Sucralfate is a basic aluminium salt of sulphated sucrose which is advocated for use in peptic ulcer disease. It is minimally absorbed after oral administration and is believed to act primarily at the ulcer site by protecting the ulcer from the effects of pepsin, acid and possibly bile salts. Controlled therapeutic trials have demonstrated that sucralfate 1g 4 times daily is effective in increasing the rate of healing of duodenal and gastric ulcer over a period of 4 to 8 weeks. Trials comparing sucralfate and cimetidine have not found any significant difference in efficacy between the drugs in small numbers of patients. A dosage of 2g daily given prophylactically decreases the rate of recurrence of duodenal ulcers, but the efficacy of sucralfate in preventing relapse of gastric ulcers has yet to be clearly demonstrated. Sucralfate is particularly well tolerated. Constipation, the most common side effect, occurs in 2% of patients. Thus, sucralfate offers an effective and well tolerated alternative for the management of peptic ulcer disease.