Diltiazem adverse effects

Adverse effects and contraindications of calcium channel blockers are described in Table 5-2. Verapamil, diltiazem, and first-generation dihydropyridines should also be avoided in patients with acute decompensated heart failure or left... 

Ventricular Rate Control is achieved by inhibiting the proportion of electrical impulses conducted from the atria to the ventricles through the AV node. Therefore, drugs that are effective for ventricular rate control are those that inhibit AV nodal impulse conduction P-blockers, diltiazem, verapamil, and digoxin (Tables 6-5 and 6-6). Amiodarone also inhibits AV nodal conduction, but is not a preferred drug for ventricular rate control in AF due to its unfavorable adverse-effect profile (Table 6-6). 

Because calcium channel antagonists may be more effective, have few serious adverse effects, and can be given less frequently than nitrates, some authorities consider them the agents of choice for variant angina. Nifedipine, verapamil, and diltiazem are all equally effective as single agents for... 

Buspirone (BuSpar) [Anxiolytic] WARNING Closely monitor for worsening depression or emergence of suicidality Uses Short-term relief of anxiety Action Antianxiety antagonizes CNS serotonin receptors Dose Initial 7.5 mg PO bid T by 5 mg q2-3d to effect usual 20-30 mg/d max 60 mg/d Contra w/ MAOI Caution [B, /-] Avoid w/ severe hepatic/renal insuff Disp Tabs SE Drowsiness, dizziness, HA, N, EPS, serotonin synd, hostility, depression Notes No abuse potential or physical/psychologic d endence Interactions T Effects W/ erythromycin, clarithromycin, itraconazole, ketoconazole, diltiazem, verapamil, grapefruit juice effects W/ carbamazepine, rifampin, phenytoin, dexamethasone, phenobarbital, fluoxetine EMS T Sedation w/ concurrent EtOH use grapefruit juice may T risk of adverse effects OD May cause dizziness, miosis, N/V symptomatic and supportive... 

Most types of smooth muscle are dependent on transmembrane calcium influx for normal resting tone and contractile responses. These cells are relaxed by the calcium channel blockers (Figure 12-3). Vascular smooth muscle appears to be the most sensitive, but similar relaxation can be shown for bronchiolar, gastrointestinal, and uterine smooth muscle. In the vascular system, arterioles appear to be more sensitive than veins orthostatic hypotension is not a common adverse effect. Blood pressure is reduced with all calcium channel blockers. Women may be more sensitive than men to the hypotensive action of diltiazem. The reduction in peripheral vascular resistance is one mechanism by which these agents may benefit the patient with angina of effort. Reduction of coronary artery tone has been demonstrated in patients with variant angina. 

The pharmacokinetic properties of these drugs are set forth in Table 12-5. The choice of a particular calcium channel-blocking agent should be made with knowledge of its specific potential adverse effects as well as its pharmacologic properties. Nifedipine does not decrease atrioventricular conduction and therefore can be used more safely than verapamil or diltiazem in the presence of atrioventricular conduction abnormalities. A combination of verapamil or diltiazem with 3 blockers may produce atrioventricular block and depression of ventricular function. In the presence of overt heart failure, all calcium channel blockers can cause further worsening of heart failure as a result of their negative inotropic effect. Amlodipine, however, does not increase the mortality of patients with heart failure due to nonischemic left ventricular systolic dysfunction and can be used safely in these patients. 

Adverse effects Verapamil and diltiazem have negative inotropic properties and therefore may be contraindicated in patients with preexisting depressed cardiac function. Both drugs can also cause a decrease in blood pressure caused by peripheral vasodilation. 

In a randomized placebo-controlled trial, the possible interactions of buspirone with verapamil and diltiazem were investigated. Both verapamil and diltiazem considerably increased plasma buspirone concentrations, probably by inhibiting CYP3A4. Thus, enhanced effects and adverse effects of buspirone are possible when it is used with verapamil, diltiazem, or other inhibitors of CYP3A4 (24). 

Omeprazole, like cimetidine, can impair benzodiazepine metabolism and lead to adverse effects (SEDA-18, 43). Other drugs, including antibiotics (erythromycin, chloramphenicol, isoniazid), antifungal drugs (ketoconazole, itraconazole, and analogues), some SSRIs (fluoxetine, paroxetine), other antidepressants (nefazodone), protease inhibitors (saquinavir), opioids (fentanyl), calcium channel blockers (diltiazem, verapamil), and disulfiram also compete for hepatic oxidative pathways that metabolize most benzodiazepines, as well as zolpidem, zopiclone, and buspirone (SEDA-22,39) (SEDA-22,41). 

A patient taking diltiazem developed the signs and symptoms of mania (114) and another developed mania with psychotic features (115). There have also been reports that nifedipine can cause agitation, tremor, belligerence, and depression (116), and that verapamil can cause toxic delirium (117). Nightmares and visual hallucinations have been associated with nifedipine (118). Depression has been reported as a possible adverse effect of nifedipine (119). 

Ueno S, Hara Y. Lambert-Eaton myasthenic syndrome without anti-calcium channel antibody adverse effect of calcium antagonist diltiazem. J Neurol Neurosurg Psychiatry 1992 55(5) 409-10. 

Adverse effects and contraindications of calcium channel blockers are described in Table 16. Verapamil, diltiazem, and first-generation dihydropyridines also should be avoided in patients with acute decompensated heart failure or LV dysfunction because they can worsen heart failure and potentially increase mortality secondary to their negative inotropic effects. In patients with heart failure requiring treatment with a calcium channel blocker, amlodipine is the preferred agent. ... 

Adverse effects are bradycardia, headache, flushing, palpitations and ankle oedema. There is an increased risk of myopathy if diltiazem is used together with statins (see page 77). 

Toxicity of Ca Channel Blockers The major adverse effect of intravenous verapamil or diltiazem is hypotension, particularly with bolus administration. This is a particular problem if the drugs are used mistakenly in patients with ventricular tachycardia misdiagnosed as AV nodal reentrant tachycardia. Hypotension also is frequent in patients receiving other vasodilators, including quinidine, and in patients with underlying left ventricular dysfunction, which the drugs can exacerbate. Severe sinus bradycardia or AV block also occurs, especially in patients also receiving P blockers. With oral therapy, these adverse effects tend to be less severe. 

Diltiazem and verapamil can markedly raise the plasma levels of buspirone, increasing the likelihood of adverse effects. 

Concurrent use is unquestionably valuable and uneventful in many patients, but severe adverse effects can develop. This is well established. A not dissimilar adverse interaction can occur with verapamil , (p.841). On the basis of 6 reports, the incidence of symptomatic bradyarrhythmia was estimated to be about 10 to 15%. It can occur with different beta blockers, even with very low doses, and at any time from within a few hours of starting treatment to 2 years of concurrent use. The main risk factors seem to be ventricular dysfunction, or sinoatrial or AV nodal conduction abnormalities. Note that these are usually contraindications to the use of diltiazem. Patients with normal ventricular function and no evidence of conduction abnormalities are usually not at risk. Concurrent use should be well monitored for evidence of adverse effects. Changes in the pharmacokinetics of the beta blockers may also occur, but these changes are probably not clinically important. 

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