Pravastatin. A review of its pharmacological properties and therapeutic potential in hypercholesterolaemia.

Pravastatin is an HMG-CoA reductase inhibitor which reduces plasma cholesterol levels by inhibiting de novo cholesterol synthesis and increasing the receptor-mediated catabolism of low density lipoprotein (LDL). Several large multicentre placebo-controlled trials have shown that pravastatin reduces total and LDL-cholesterol levels in a dose-proportional manner in patients with familial or nonfamilial hypercholesterolaemia. Reductions in LDL-cholesterol levels reported in the largest study were 18% (10 mg/day), 23% (20 mg/day) and 31% (40 mg/day) after 12 weeks. Once-daily administration appears to be as effective as two daily doses. Pravastatin consistently increases HDL-cholesterol levels and decreases levels of total triglycerides but these changes are not dose dependent. At the study dosages used, the antihypercholesterolaemic effects of pravastatin were superior to those of bezafibrate and clinofibrate, and were similar to those of simvastatin, lovastatin, gemfibrozil and cholestyramine although in some studies a trend towards a superior effect with pravastatin was seen. Pravastatin did not reduce HDL-cholesterol like probucol, or increase triglyceride levels like cholestyramine. Combined treatment with pravastatin and cholestyramine or colestipol enhances the cholesterol-lowering effects of either drug administered alone and offsets the increase in total triglyceride levels seen with cholestyramine or colestipol therapy. Pravastatin is well tolerated during treatment of up to 24 months but longer term tolerability has not yet been established. The effect of provastatin on cardiovascular events related to elevated plasma cholesterol levels is under investation in several large scale regression and primary and secondary prevention trials.(ABSTRACT TRUNCATED AT 250 WORDS)

Bisoprolol. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in hypertension and angina pectoris.

Bisoprolol is a beta 1-adrenoceptor antagonist with no partial agonist (intrinsic sympathomimetic) activity or membrane stabilising (local anaesthetic) activity. The oral bioavailability of bisoprolol is high (90%) and the drug has a long elimination half-life which allows once-daily administration; in addition, it is hepatically and renally cleared in equal proportions. In non-comparative studies, and comparative trials, bisoprolol proved effective, and as efficacious as atenolol, low doses of metoprolol, diuretics and nifedipine SR in hypertension, and atenolol and verapamil in stable angina pectoris. Bisoprolol has been well tolerated in most patients. Thus, bisoprolol is an effective alternative to other beta-adrenoceptor antagonists in patients with mild to moderate essential hypertension or stable angina pectoris. Furthermore, its unique pharmacokinetic properties may offer advantages in selected patients. However, the results of further comparative studies with established agents in the treatment of hypertension and angina pectoris are still awaited so that a final assessment of the relative place in therapy of bisoprolol in these disease states may be made.

Nisoldipine. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in the treatment of angina pectoris, hypertension and related cardiovascular disorders.

Nisoldipine is an orally administered calcium entry blocking drug structurally related to nifedipine. In limited clinical trials it has been shown to be effective and relatively well tolerated in the treatment of patients with chronic stable angina pectoris and mild to moderate essential hypertension. As for all dihydropyridine-calcium antagonists, its major properties include potent peripheral and coronary vasodilation and improvement in myocardial oxygen supply relative to demand. These actions occur without depression of cardiac conduction or left ventricular function. Short term clinical trials have shown nisoldipine to produce both symptomatic and objective improvements in patients with chronic angina of effort and have suggested a benefit in vasospastic angina. A small number of comparative trials indicate that nisoldipine is equally as effective as nifedipine. In addition, in combination with beta-adrenoceptor blockade nisoldipine appears to offer additional benefit compared with beta-blockade alone and is well tolerated. In patients with mild to moderate essential hypertension nisoldipine monotherapy, in 1 or 2 daily doses, has maintained blood pressure control and has also been a useful addition to diuretics and beta-adrenoceptor blocking drugs in patients with poorly controlled disease. Side effects appear to be dose related, generally mild and transient, and are primarily those resulting from potent peripheral vasodilation - headache, flushing and pretibial or ankle oedema. Although studies to date are promising, there are no published long term studies (greater than 1 year) of nisoldipine in comparison with other calcium entry blockers and other drugs currently in clinical use for the treatment of angina pectoris or hypertension. Until such studies are completed the exact place of nisoldipine in the treatment of these diseases remains to be established.

Diclofenac sodium. A reappraisal of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy.

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) advocated for use in painful and inflammatory rheumatic and certain non-rheumatic conditions. It is available in a number of administration forms which can be given orally, rectally or intramuscularly. Conveniently, dosage adjustments are not required in the elderly or in those patients with renal or hepatic impairment. The drug has a relatively short elimination half-life, which limits the potential for drug accumulation. In numerous clinical trials the efficacy of diclofenac is equivalent to that of the many newer and established NSAIDs with which it has been compared. As an analgesic it has a fast onset and long duration of action. When administered intramuscularly it is at least comparable to, and frequently superior to, many narcotic and spasmolytic combinations in renal and biliary colic. Extensive clinical experience has been gained with diclofenac, clearly establishing its safety profile. It is well tolerated compared with other NSAIDs and rarely produces gastrointestinal ulceration or other serious side effects. Thus, diclofenac can be considered as one of the few NSAIDs of 'first choice' in the treatment of acute and chronic painful and inflammatory conditions.

Ocular metipranolol. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in glaucoma and ocular hypertension.

Metipranolol is a non-selective beta-adrenoceptor blocking agent used for the topical treatment of elevated intraocular pressure in patients with chronic open angle glaucoma or ocular hypertension. In double-blind comparative studies of up to 4 months duration, metipranolol 0.1 to 0.6% produced comparable reductions in intraocular pressure to timolol 0.25 to 0.5% and levobunolol 0.5%, lowering pressure by about 20 to 29% from baseline. Metipranolol has been well tolerated by most patients, producing only minor changes in objective measurements of ophthalmic status and systemic parameters. Similarly, subjective ophthalmic complaints have been minimal although reports of initial stinging or burning upon instillation have occurred. Further published reports, in which larger numbers of patients are treated over extended periods, are needed to confirm the drug's apparent long term comparative efficacy. Studies of ocular metipranolol to date are encouraging, and the drug demonstrates a lasting intraocular pressure reducing effect with good tolerability. Thus, ocular metipranolol provides a viable alternative to ocular timolol and levobunolol in the topical treatment of chronic open angle glaucoma or ocular hypertension.

Ocular sodium cromoglycate. An overview of its therapeutic efficacy in allergic eye disease.

Sodium cromoglycate stabilizes mast cell membranes and prevents the release of histamine and other biochemical mediators. When topically applied to the eye before allergen exposure, ocular sodium cromoglycate prevents many of the signs and symptoms associated with type I allergic reactions (which includes hayfever, acute allergic and chronic allergic conjunctivitis, and vernal keratoconjunctivitis) and giant papillary conjunctivitis. Although difficulties exist in evaluating clinical trials in allergic eye disease, both open and controlled studies have shown ocular sodium cromoglycate to be very effective in relieving the subjective symptoms and clinical signs of the above ocular disorders. In addition, ocular sodium cromoglycate may decrease the need for supplementary oral antihistamines and, more importantly, the need for ocular corticosteroids, thus decreasing the incidence of steroid-induced ocular side effects. However, in severe cases and in instances of acute exacerbation of symptoms, the combined ocular application of sodium cromoglycate and corticosteroids may be very effective. No systemic or severe adverse reactions have been attributed to ocular sodium cromoglycate, which is not surprising since systemic drug absorption from the eye is minimal. However, transient local stinging and burning have been reported. Thus, although further studies in giant papillary conjunctivitis and comparative studies with corticosteroids in allergic conjunctivitis and vernal keratoconjunctivitis are needed to more clearly define the extent of benefits that may be obtained from ocular sodium cromoglycate, it is clear that the safety and efficacy of the drug in type I allergic eye diseases is such that it should be considered as a first-line agent when drug therapy of these disorders is indicated.

Tiaprofenic acid. A review of its pharmacological properties and therapeutic efficacy in rheumatic diseases and pain states.

Tiaprofenic acid is a new non-steroidal anti-inflammatory agent advocated for use in rheumatoid arthritis, osteoarthritis, musculoskeletal disorders, soft-tissue injuries and inflammatory conditions and acute pain of varying origin. Published data suggest that tiaprofenic acid 600 mg daily in 2 or 3 divided doses is comparable in effectiveness with aspirin, diclofenac, ibuprofen, indomethacin, naproxen, piroxicam and sulindac in the treatment of rheumatoid arthritis and osteoarthritis. More controlled clinical trials are necessary to evaluate its potential in rheumatic conditions other than rheumatoid arthritis and osteoarthritis. In controlled studies in patients with acute pain following surgery or trauma, tiaprofenic acid was more effective than placebo and as effective as aspirin and indomethacin. While tiaprofenic acid produced fewer side effects than aspirin in rheumatoid arthritis treatment, and indomethacin in the treatment of osteoarthritis, results have generally shown the short term tolerability of tiaprofenic acid to be similar to that of other non-steroidal anti-inflammatory drugs. As no one of the non-steroidal anti-inflammatory agents is the most suitable drug for all patients requiring such therapy, tiaprofenic acid should be considered along with other drugs of this type in the therapy of arthritic conditions and of acute postoperative or posttraumatic pain.

Nedocromil sodium. An updated review of its pharmacological properties and therapeutic efficacy in asthma.

Nedocromil sodium, the disodium salt of a pyranoquinoline dicarboxylic acid, has anti-inflammatory properties in vitro, in animal models of asthma, and in humans, as evidenced by inhibition of inflammatory cell activation and mediator release, early and late allergen-induced bronchoconstriction and airway hyperresponsiveness. Recent therapeutic trials confirm the safety and efficacy of inhaled nedocromil sodium as adjunctive therapy in adult patients whose asthma is not adequately controlled by beta-agonists alone. Nedocromil sodium has also been shown to improve symptoms when added to existing treatment with methylxanthines and corticosteroids. Some studies show nedocromil sodium to be successful replacement therapy for methylxanthines, in addition to enabling a modest reduction in inhaled corticosteroids in some patients. Thus, nedocromil sodium may be suitable in patients with asthma as an adjunct to existing therapy, as an alternative to regularly administered oral and inhaled beta-agonists and oral methyl-xanthines, and potentially, to low dose inhaled corticosteroids as maintenance therapy in patients with mild to moderate asthma being considered for corticosteroid therapy.

Zonisamide. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in epilepsy.

Zonisamide is a 1,2 benzisoxazole derivative and the first agent of this chemical class to be developed as an antiepileptic drug. It has shown activity in various animal models of epilepsy, and although a detailed mode of action awaits clarification it appears to block the propagation/spread of seizure discharges and to suppress the epileptogenic focus. Clinical experience with zonisamide in Japan has documented its efficacy in the treatment of partial seizures (partial-onset generalised tonic-clonic, simple partial and/or complex partial seizures), and to a more variable extent, generalised tonic-clonic, generalised tonic (mainly seen in symptomatic generalised epilepsies including Lennox-Gastaut Syndrome) and compound/combination seizures (including those refractory to treatment with other antiepileptic drugs). Other generalised seizure types have also responded to therapy with zonisamide, although only small patient numbers were studied. Zonisamide has demonstrated efficacy equivalent to that of carbamazepine in patients with (mainly) partial seizures, and to that of valproic acid in a small study of children (n = 32) with generalised seizures. Animal studies suggest that zonisamide possesses a more favourable therapeutic index than most other antiepileptic drugs. However, clinical trials conducted to date, have not confirmed any overt tolerability advantage. Indeed, whereas the recommended therapeutic plasma zonisamide concentration is 20 mg/L, clinical investigations have associated adverse events with plasma zonisamide concentrations of > 30 mg/L, suggesting the usefulness of therapeutic drug monitoring. Moreover, although plasma concentrations of zonisamide are empirically regarded to be proportional to therapeutic doses in patients in Japan, nonlinear pharmacokinetics have been reported for this drug in patients in the US and may further complicate its use in this patient population. Additional pharmacokinetic studies will help to establish the change in pharmacokinetic profile that occurs with dosage titration in patients outside Japan. Among 700 patients treated with zonisamide in Europe/US, a high incidence of renal calculi (1.9%) has been noted, however, the causal relationship to zonisamide is disputed. Indeed, although urinary lithiasis has also been recorded for patients in Japan, the aetiology, incidence and spontaneous regression of this condition suggest that it is not a serious problem for this patient population. Until this difference is clarified, it is likely that zonisamide will find its greatest use in the treatment of patients in Japan. Like many other established antiepileptic drugs, available data suggest the propensity for zonisamide to alter the pharmacokinetic profile of other anticonvulsant agents, although severe interactions appear to be unlikely.(ABSTRACT TRUNCATED AT 400 WORDS)

Finasteride. A review of its potential in the treatment of benign prostatic hyperplasia.

Finasteride is a novel therapeutic agent that selectively inhibits the enzyme 5 alpha-reductase, thereby reducing prostatic dihydrotestosterone (DHT) levels and prostate size. In men with symptomatic benign prostatic hyperplasia (BPH), these effects have been associated with improvements in peak urinary flow rate and urological symptoms; withdrawal from therapy, however, results in regrowth of the adenoma and long term therapy is therefore necessary. Although the magnitude of clinical improvement seen with finasteride has been perceived to be modest [especially when compared with that associated with transurethral resection of the prostate (TURP)], it has been maintained in the medium term (up to 2 years) and thus may represent significant reversal of disease progression. Such beneficial effects, however, may not become apparent until completion of at least 6 months of therapy. Furthermore, since clinical studies have been unable to proactively identify a responsive subgroup, a trial period of 6 or possibly 12 months is necessary to assess patient responsiveness. Despite these potential shortcomings, the benefits of therapy appear to outweigh the risks. Indeed, finasteride is well tolerated; most adverse events have been related to sexual dysfunction (decreased libido, ejaculation disorders and impotence) and occurred in only a small proportion (about 2 to 3%) of patients. Moreover, although there has been concern that finasteride might mask the detection of prostate cancer through its decremental effects on serum prostate specific antigen (PSA) levels, careful monitoring in clinical trials appears to have avoided this problem. Thorough pretreatment assessment and periodic follow-up examinations for malignancy are therefore required in clinical practice. The role of finasteride in the treatment of patients with BPH is still emerging and will no doubt gain in clarity with further planned investigations. TURP (or other invasive procedures such as the insertion of prostatic stents in patients unsuitable for resection), continues to be the mainstay of therapy for those patients with severe symptomatic BPH. However, available data support a first line role for finasteride in the treatment of patients with uncomplicated symptomatic BPH. Within this setting, finasteride appears to offer a needed additional treatment option for those patients in whom surgery is not indicated, and may be of special benefit to the considerable proportion of patients who opt not to undergo prostatectomy.

Quinapril. A reappraisal of its pharmacology and therapeutic efficacy in cardiovascular disorders.

Following systemic absorption, quinapril is converted by de-esterification to quinaprilat (the active diacid metabolite), an inhibitor of angiotensin converting enzyme (ACE). Pharmacodynamic studies in animals indicate inhibition of ACE both in plasma and at tissue sites, such as the arterial wall and heart, following administration of quinapril. Tissue ACE inhibition may be an important component of the mechanism of action of quinapril (and other ACE inhibitors) in achieving favourable effects in cardiovascular disorders. Quinaprilat has a short elimination half-life (approximately 2 hours), but binds potently to and dissociates slowly from ACE, thus allowing once or twice daily administration of quinapril in the treatment of patients with hypertension or congestive heart failure. Quinapril 10 to 40 mg/day has achieved adequate control of blood pressure in most patients with essential hypertension in clinical trials. Some patients required quinapril dosages up to 80 mg/day and/or concomitant diuretic therapy. Titrating quinapril dosages from 10 to 40 mg/day increased response rates without increasing the incidence or severity of adverse events. Addition of hydrochlorothiazide to quinapril therapy improved response rates by approximately 10 to 20% in patients with hypertension. In general, blood pressure control with quinapril monotherapy was similar to that achieved with enalapril or other standard antihypertensive agents in comparative trials. Quinapril < or = 40 mg/day improved exercise tolerance, reduced the severity and frequency of symptoms, and improved functional (New York Heart Association) class in most clinical studies of patients with congestive heart failure. In addition, beneficial haemodynamic and echocardiographic changes achieved with quinapril were maintained for up to 1 year with continued administration to such patients, but its effect on survival in patients with congestive heart failure has not been reported. The tolerability profile of quinapril is broadly similar to that of other ACE inhibitors; pooled data from clinical trials indicated that 12% of patients with hypertension or congestive heart failure receiving quinapril experienced a treatment-related adverse effects compared with 15% of enalapril recipients and 16% of captopril recipients. Thus, quinapril has clearly established a role as an effective and well tolerated alternative to other ACE inhibitors for the treatment of hypertension and congestive heart failure. While effects of quinapril on survival of patients with congestive heart failure have not been determined, large intervention studies have demonstrated improved mortality rates with other ACE inhibitors. Further studies, including a large ongoing trial of normotensive patients with coronary artery disease but normal left ventricular function, may also establish a role for quinapril in treating patients with ischaemic heart disease.

Epoetin (recombinant human erythropoietin). A review of its pharmacodynamic and pharmacokinetic properties and therapeutic potential in anaemia and the stimulation of erythropoiesis.

Epoetin (recombinant human erythropoietin) is a sialoglycoprotein hormone that appears to be immunologically and biologically equivalent to the endogenous compound, enhancing erythropoiesis dose-proportionally. The therapeutic efficacy of epoetin in the treatment of anaemia associated with chronic renal failure has been established, with almost all patients responding with increases in haematocrit and haemoglobin levels, and improvements in quality of life. Some patients demonstrate relative epoetin resistance and require a higher dosage to achieve target haemoglobin and haematocrit levels. Maintenance of an adequate iron supply is essential and iron supplementation is recommended if serum ferritin is below 100 to 150 micrograms/L or transferrin saturation is less than 20%. The incidence of serious adverse effects may be reduced by maintaining a moderate rate of increase in the haematocrit with close monitoring of blood pressure and dialysis efficacy. Individual titration of epoetin dosage is recommended, with increases made in small increments to achieve haematocrit and haemoglobin levels of 30 to 33% and 10 to 12 g/dl, respectively, although the optimal haematocrit for each patient should be individually determined. Some patients will also require a modest increase in heparin dosage because of a possible increase in clotting tendency. Hypertension is the most common adverse effect in patients with chronic renal failure, occurring partially as a result of increasing blood viscosity and peripheral vascular resistance with the correction of anaemia. Maintenance epoetin therapy has been given for more than 2 years without a decrease in responsiveness and does not appear to adversely affect the outcome of renal transplantation. Thus, epoetin represents a significant therapeutic advance in the treatment of anaemia associated with chronic renal failure and should be considered a first option for these patients. Its potential value in the treatment of anaemia associated with other disorders and in facilitating autologous blood donation remains to be fully determined.

Mesalazine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in chronic inflammatory bowel disease.

Mesalazine (5-aminosalicylic acid; mesalamine), the active moiety of sulphasalazine (salazosulfapyridine), is available in specially formulated oral and rectal forms for the treatment of active ulcerative colitis of mild to moderate severity and for maintenance therapy during disease remission. Tablets or capsules coated with acrylic-based resin and tablets containing microgranules coated with ethylcellulose deliver mesalazine to the distal small intestine and colon, thus avoiding the need for the carrier, sulphapyridine, which is responsible for many of the adverse effects associated with sulphasalazine. Since mesalazine is released in the small intestine from some coated preparations in contrast to sulphasalazine, these oral formulations have therapeutic potential in Crohn's disease. A limited number of therapeutic trials suggest that orally administered mesalazine 1.5 to 2.4g daily is of similar efficacy to sulphasalazine 2 to 3g daily in patients with mild to moderate ulcerative colitis. The efficacy of mesalazine enemas has been more widely investigated, a dose of 1 to 4g once daily being consistently more effective than placebo and apparently similar to enemas of prednisone 25mg or oral sulphasalazine 3g. Initial results suggest that mesalazine 4g enemas may be more effective than those containing hydrocortisone 100mg. Mesalazine and sulphasalazine in approximately equivalent oral dosages are similarly effective in maintaining remission in ulcerative colitis. Orally administered coated mesalazine is generally well tolerated by about 85% of patients allergic to or intolerant of sulphasalazine, the remainder experiencing similar reactions to both drugs. Adverse effects of mesalazine enemas are confined to local irritation and effects resulting from enema-tip insertion. Thus, orally administered coated mesalazine is a suitable alternative to sulphasalazine in the treatment of patients with mild to moderate active distal ulcerative colitis and for maintaining remission particularly in patients allergic to or intolerant of sulphasalazine. In patients who find enema therapy acceptable, mesalazine enemas are effective and well tolerated.

Verapamil. An updated review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in hypertension.

Although verapamil is a well-established treatment for angina, cardiac arrhythmias and cardiomyopathies, this review reflects current interest in calcium antagonists as anti-hypertensive agents by focusing on the role of verapamil in hypertension. Verapamil is a phenylalkylamine derivative which antagonises calcium influx through the slow channels of vascular smooth muscle and cardiac cell membranes. By reducing intracellular free calcium concentrations, verapamil causes coronary and peripheral vasodilation and depresses myocardial contractility and electrical activity in the atrioventricular and sinoatrial nodes. Verapamil is well suited for the management of essential hypertension since it produces generalised systemic vasodilation resulting in a marked reduction in systemic vascular resistance and, consequently, blood pressure. Evidence from clinical studies supports the role of oral verapamil as an effective and well-tolerated first-line treatment for the management of patients with mild to moderate essential hypertension. Clinical studies have shown that verapamil is more effective the higher the pretreatment blood pressure and some authors have found a more pronounced antihypertensive effect in older patients or in patients with low plasma renin activity. Sustained release verapamil formulations are available for oral administration which, as a single daily dose, are as effective in lowering blood pressure over 24 hours as equivalent doses of conventional verapamil formulations given 3 times daily. As a first-line antihypertensive agent, oral verapamil is equivalent to several other calcium antagonists, beta-blockers, diuretics, angiotensin-converting enzyme (ACE) inhibitors and other vasodilators, and is not associated with many of the common adverse effects of these treatments. Verapamil may be preferred as an alternative first-line antihypertensive treatment to diuretics in elderly patients because it has similar efficacy in these patients without causing the adverse effects commonly linked with diuretic treatment. Furthermore, because verapamil does not cause bronchoconstriction, it may be used in preference to beta-blockers in patients with asthma or chronic obstructive airway disease. Reflex tachycardia, orthostatic hypotension or development of tolerance is not evident following verapamil administration. As a second- or third-line treatment for patients refractory to established antihypertensive regimens, verapamil produces marked blood pressure reductions when combined with diuretics and/or ACE inhibitors, beta-blockers and vasodilators such as prazosin.(ABSTRACT TRUNCATED AT 400 WORDS)

Nimodipine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in cerebrovascular disease.

Nimodipine is a dihydropyridine calcium antagonist which has been shown to dilate cerebral arterioles and increase cerebral blood flow in animals and humans. It has potential in the treatment of a range of cerebrovascular disorders. Major interest to date, however, has focused on its use in the prevention and treatment of the delayed ischaemic neurological deficits that frequently occur in patients with subarachnoid haemorrhages as a result of sustained cerebral vasospasm. Initial studies in which patients were treated with an intravenous infusion of nimodipine for up to 2 weeks, followed by oral treatment for 7 days, indicated that a higher proportion of patients than would normally be expected recovered with little or no permanent neurological damage. In a number of controlled studies oral nimodipine treatment for 3 weeks significantly decreased mortality rates and increased the number of patients who had a 'good' neurological outcome as compared with placebo treatment. In some of these trials fewer of the nimodipine-treated patients developed neurological deficits during the treatment period, but in none was there a significant effect on the incidence of angiographic vasospasm. It would seem that other pharmacological actions, such as increasing collateral blood flow to underperfused regions or a direct anti-ischaemic effect at the cellular level, may contribute to the clinical benefits obtained with nimodipine treatment. Preliminary results suggest that nimodipine is potentially useful in other cerebrovascular disorders, particularly ischaemic stroke. To date, nimodipine has been well-tolerated, the only adverse effects of any significance being reductions in the blood pressure of some patients and reversible increases in liver enzymes during intravenous therapy. Thus, nimodipine has significant potential in the treatment of patients with subarachnoid haemorrhage. Wider clinical use should confirm its value as a significant addition to the very limited range of therapeutic choices currently available for patients with this disorder.

Abciximab (c7E3 Fab). A review of its pharmacology and therapeutic potential in ischaemic heart disease.

Abciximab (c7E3 Fab) is a chimaeric human-murine monoclonal antibody Fab (fragment antigen binding) fragment. It binds to the platelet glycoprotein IIb/IIIa receptor and inhibits platelet aggregation. In two double-blind placebo-controlled trials, abciximab therapy reduced the incidence of ischaemic complications during the initial postoperative period (30 days or until hospital discharge) in high-risk patients undergoing percutaneous coronary angioplasty or directional atherectomy. It also reduced the incidence of clinical restenosis compared with placebo during longer term (6 months) follow-up of these patients. Although abciximab delayed the need for coronary artery bypass graft surgery, it did not reduce the proportion of patients ultimately requiring this procedure. The drug was generally well tolerated in clinical trials, with bleeding complications being the major adverse event. Abciximab is at an early stage of its clinical introduction and, not surprisingly, some aspects of its use remain to be further assessed. Nevertheless, results show the addition of abciximab to standard aspirin plus heparin therapy during coronary angioplasty or directional atherectomy improves the outcome of the revascularisation procedure in patients with a high risk of subsequent acute ischaemic complications. The results of further trials defining the optimum dosage of heparin when administered with abciximab, and evaluating the role of abciximab in a wider range of patients, are eagerly awaited.

Dornase alfa. A review of its pharmacological properties and therapeutic potential in cystic fibrosis.

By cleaving neutrophil-derived DNA present in the infected lungs of patients with cystic fibrosis (CF), dornase alfa (recombinant human deoxyribonuclease I) reduces the adhesiveness and viscoelasticity of CF sputum. Well designed clinical studies performed in patients with CF and mild to moderate pulmonary disease [forced vital capacity (FVC) > or = 40% of predicted value] show that aerosolised dornase alfa improves lung function, achieving a 6 to 7% increase from baseline in forced expiratory volume in 1 second (FEV1) after 6 months' therapy. Improvements in general well-being and CF-related symptoms were also noted by patients. Importantly, dornase alfa reduced the relative risk of respiratory exacerbations requiring parenteral antibiotics by 22 to 34% compared with placebo. Short term studies with dornase alfa in patients with more severe pulmonary disease (FVC < 40% of predicted value) and in those with acute infectious exacerbations did not reveal any significant improvements in pulmonary function, although long term studies are required to fully determine efficacy. Voice alteration, laryngitis or rash may develop with dornase alfa therapy, although more clinical experience with the agent is required to define its tolerability profile. Anaphylaxis has not been reported with dornase alfa to date. In summary, aerosolised dornase alfa offers modest improvements in lung function and, importantly, a reduced risk of respiratory exacerbations in patients with CF and an FVC > or = 40% of the predicted value, thus representing an important adjunct agent in this patient group.

Guanfacine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in the treatment of hypertension.

Guanfacine, a phenylacetyl-guanidine derivative, is a centrally acting alpha-adrenoceptor agonist, with a mechanism of antihypertensive action similar to that of clonidine. It reduces blood pressure in patients with essential hypertension at least as effectively as clonidine or methyldopa. Like lower doses of clonidine, guanfacine can be given once daily due to its relatively long elimination half-life. Although dry mouth and sedation occur frequently with higher doses of guanfacine, their incidence is lower than with other centrally acting antihypertensives; in addition, other troublesome side effects such as orthostatic hypotension or sexual dysfunction also occur much less with guanfacine than with other centrally acting antihypertensive agents. While a withdrawal syndrome may occur on abruptly discontinuing guanfacine administration, the symptoms are generally mild, and the incidence of withdrawal symptoms appears lower than occurs with abrupt withdrawal of clonidine. Thus, guanfacine is an effective and well tolerated alternative to other centrally acting antihypertensive drugs. Whether its final place in therapy will be as an alternative 'second-line' drug, or as initial monotherapy in patients with mild to moderate hypertension, remains to be clarified in comparative studies with diuretics, calcium antagonists, and beta-adrenoceptor blocking drugs.

Indoramin. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in hypertension and related vascular, cardiovascular and airway diseases.

Indoramin is a postsynaptic selective alpha 1-adrenoceptor antagonist used in the treatment of hypertension. In contrast to some other alpha-blockers, animal studies suggest that its blood pressure lowering effect results from relaxation of peripheral arterioles as a consequence of blockade of postsynaptic alpha 1-adrenoceptors. Furthermore, unlike some other alpha-blockers, this lowering of blood pressure is rarely associated with reflex tachycardia or postural hypotension. Therapeutic trials have shown indoramin to be effective in lowering blood pressure in all grades of hypertension: mild and moderate hypertension when used alone, but generally in combination with a thiazide diuretic, and in moderate to moderately severe hypertension when used in combination with a beta-blocker and diuretic. In a few small comparative studies, no significant difference was found in the blood pressure lowering effects between indoramin and methyldopa, propranolol and prazosin. Side effects were similar for indoramin, propranolol and methyldopa; however in the 1 comparative study with prazosin, prazosin produced a lower incidence of sedation. Indeed, the most common side effect with indoramin therapy has been sedation of a mild to moderate and/or transient nature, reported in about 19% of cases. Other side effects which have sometimes led to a withdrawal of indoramin treatment have been dry mouth, dizziness, and in males, failure of ejaculation; however, side effects may be reduced by starting therapy with smaller doses and titrating more gradually.

Nitrendipine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in the treatment of hypertension.

Nitrendipine is a calcium entry blocker shown to inhibit the movement of calcium through the 'slow channel' of cardiac and vascular smooth muscle, thus inducing peripheral vasodilation with consequent reductions in elevated blood pressure. As evidenced by clinical trials, nitrendipine promptly lowers blood pressure in patients with mild to moderate hypertension, and sustains this effect during long term administration. Combining nitrendipine with other antihypertensive agents such as diuretics or beta-blockers often results in successful treatment in patients unresponsive to nitrendipine monotherapy. Headache, oedema, flushing and palpitations commonly occurring during treatment with nitrendipine are generally mild, usually subsiding with continued therapy. Thus, although additional long term studies are required to properly assess the relative merits of the drug compared with other antihypertensives, by providing the clinician with an effective and safe alternative to traditional therapies, nitrendipine represents a step forward in the treatment of mild to moderate hypertension.