Myocardial infarction calcium channel blockers

Retrospective case-control studies reported that immediate-acting nifedipine increased the risk of myocardial infarction in patients with hypertension. Slow-release and long-acting vasoselective calcium channel blockers are usually well tolerated. Flowever, dihydropyridines, compared with angiotensin-converting enzyme (ACE) inhibitors, have been reported to increase the risk of adverse cardiac events in... 

In patients with unstable angina, immediate-release short-acting calcium channel blockers can increase the risk of adverse cardiac events and therefore are contraindicated (see Toxicity, above). However, in patients with non-Q-wave myocardial infarction, diltiazem can decrease the frequency of postinfarction angina and may be used. 

Glucagon has also been used to stimulate insulin and C-peptide secretion, to see whether the islets still produce insulin, as a stimulatory test during pheochromocytoma, hyperinsulinism, and Zollinger-Ellison syndrome, or as an additive in upper gastrointestinal X-ray investigations (0.5-1 mg). It has been used in myocardial infarction, although its inotropic effects may present a risk. It has also been used to treat overdoses with beta-blockers (3) and calcium channel blockers (4), although its efficacy in such cases has only been demonstrated in animals (5) and to treat overdose with tricyclic antidepressants (6,7). 

Some issues, however, have developed fairly recently regarding the safety of these drugs in treating hypertension. Several studies noted that use of certain calcium channel blockers (i.e., the short-acting form of nifedipine) was associated with an increased risk of myocardial infarction when these drugs were adminis-... 

There has been some concern about the safety of the calcium channel blockers. In particular, reports indicated that certain calcium channel blockers, such as the short-acting form of nifedipine, may be associated with an increased risk of myocardial infarction in certain patients (older patients with hypertension, patients with unstable angina).21,29... 

Activation of platelets is considered an essential process for arterial thrombosis. Thus, treatment with platelet-inhibiting drugs such as aspirin and ticlopidine or clopidogrel is indicated in patients with transient ischemic attacks and strokes or unstable angina and acute myocardial infarction. In angina and infarction, these drugs are often used in conjunction with -blockers, calcium channel blockers, and fibrinolytic drugs. 

Overdose is common amongst users (up to 22% of heavy users report losing consciousness). The desired euphoria and excitement turns to acute fear, with psychotic symptoms, convulsions, hypertension, haemorrhagic storke, tachycardia, arrhythmias, hyperthermia coronary vasospasm (sufficient to present as the acute coronary syndrome with chest pain and myocardial infarction) may occur, and acute left ventricular dysfunction. Treatment is chosen according to the clinical picture (and the known mode of action), from amongst, e.g. haloperidol (rather than chlorpromazine) for mental disturbance diazepam for convulsions a vasodilator, e.g. a calcium channel blocker, for hypertension glyceryl trinitrate for myocardial ischaemia (but not a p-... 

There has been some concern that the shorter-acting calcium channel blockers may adversely affect the risk of myocardial infarction and cardiac death. The evidence is based on case-control studies which cannot escape the possibility that sicker patients, i.e. with worse hypertension or angina, received calcium charmel blockade. The safety and efficacy of the class has been strengthened by the recent findings of two prospective comparisons with other antihypertensives. ... 

Oedema states associated with sodium overload, e.g. cardiac, renal or hepatic disease, and also without sodium overload, e.g. acute pulmonary oedema following myocardial infarction. Note that oedema may also be localised, e.g. angioedema over the face and neck or aroimd the ankles following some calcium channel blockers, or due to low plasma albumin, or immobility in the elderly in none of these circumstances are diuretics indicated. 

Unstable angma.The chance of myocardial infarction is high and aspirin should be used with other drugs, i.c. a [i-adrcnoceptor antagonist,a nitrate.a calcium channel blocker and possibly heparin i.v. as is judged appropriate. 

There have been many studies of the efficacy of calcium channel blockers in early and late intervention in myocardial infarction (33). These studies have failed to show convincing benefits. Indeed, in the nifedipine intervention studies there was a consistent trend towards higher mortality in the treated patients than in those taking placebo. A study in which patients were randomized to placebo or nifedipine within 48 hours of admission was terminated after 1358 patients had been recruited, because mortality at 6 months was 15.4% on nifedipine and 13.3% on placebo (34). 

Held PH, Yusuf S, Furberg CD. Calcium channel blockers in acute myocardial infarction and unstable angina an overview. BMJ 1989 299(6709) 1187-92. 

Myocardial infarction has been documented in 6% of patients who present to emergency departments with cocaine-associated chest pain (51,52). Treatment of cocaine-associated myocardial infarction has previously generally been conservative, using benzodiazepines, aspirin, glyceryl trinitrate, calcium channel blockers, and thromboljdic drugs. In the context of 10 patients with cocaine-associated myocardial infarction, who were... 

The long-term safety of dihydropyridine calcium channel blockers has been extensively debated since 1995, with reports of conflicting results from observational and randomized clinical studies about possible increases in cardiovascular mortality, myocardial infarction, and neoplastic diseases (SEDA-22, 214). Two studies have contributed to this controversy. 

The possibility that calcium channel blockers can cause cardiovascular adverse effects in pregnancy has been widely debated (SED-14, 598) (SEDA-20, 185) (SEDA-21, 208) (SEDA-22, 214). An uncomplicated non-Q wave myocardial infarction has been reported during nifedipine therapy for preterm labor (43). 

Three landmark placebo-controlled clinical trials have established the benefits of both hypertension treatment and diuretic therapy. The Systolic Hypertension in the Elderly Program (SHEP), the Swedish Trial in Old Patients with Hypertension (STOP-Hypertension), and the Medical Research Council (MRC) trial " showed significant reductions in stroke, myocardial infarction, and aU-cause cardiovascular disease and mortality with thiazide diuretic-based therapy versus placebo. These trials allowed for /3-blockers as add-on therapy for BP control. Newer agents (i.e., ACE inhibitors, angiotensin II receptor blockers [ARBs], and calcium channel blockers [CCBs]) were not available at the time of these studies. However, subsequent clinical trials have compared these newer antihypertensive agents (ACE inhibitors, ARBs, and CCBs) to diuretics." These data show similar effects, but most trials used a prospective, open-label, blinded end point (PROBE) study methodology that is... 

Chronic stable angina should be managed initially with /S-blockers because they provide better symptomatic con-trol at least as well as nitrates or calcium channel blockers and decrease the risk of recurrent myocardial infarction (Ml) and CAD mortality. 

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