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Because of the negative inotropic effects, the nondihydropyridine calcium channel blockers should be avoided (or used with caution) in individuals with cardiomyopathy. [35] Unlike beta blockers, calcium channel blockers do not decrease the responsiveness of the heart to input from the sympathetic nervous system.
Negative inotropic agents decrease myocardial contractility and are used to decrease cardiac workload in conditions such as angina. While negative inotropism may precipitate or exacerbate heart failure in the short term, certain beta blockers (e.g. carvedilol , bisoprolol and metoprolol ) have been believed to reduce long-term morbidity and ...
Non-dihydropyridine calcium channel blockers such as verapamil block the slow inward calcium current in cardiac tissues, thereby having a negatively dromotropic, chronotropic and inotropic effect. [5] This (and other) pharmacological effect makes these drugs useful in the treatment of angina pectoris.
Dihydropyridine calcium channel blockers can produce negative inotropic effects and exacerbate heart failure. Heart failure patients should be monitored carefully. Cleviprex gives no protection against the effects of abrupt beta-blocker withdrawal. Most common adverse reactions (>2%) are headache, nausea, and vomiting.
Itraconazole (Onmel/Sporanox) exhibits a negative inotropic effect on the heart and thus could spur an additive effect when used concomitantly with isradipine. Itraconazole also inhibits an important cytochrome liver enzyme (CYP 450 3A4) which is needed to metabolize isradipine and other calcium channel blockers.
Negative inotropic effects can be detected in vitro, but such effects have not been seen in intact animals at therapeutic doses. Among the two stereoisomers [R(+), S(–)], the (–) isomer has been reported to be more active than the (+) isomer. [46] Serum calcium concentration is not affected by amlodipine.
Calcium channel blockers are generally contraindicated due to their negative inotropic effect, particularly in cardiomyopathy caused by amyloidosis. [ 18 ] [ 19 ] Digoxin, calcium channel blocking drugs and beta-adrenergic blocking agents provide little benefit, except in the subgroup of restrictive cardiomyopathy with atrial fibrillation. [ 20 ]
Molecules that act as channel blockers are important in the field of pharmacology, as a large portion of drug design is the use of ion channel antagonists in regulating physiological response. The specificity of channel block molecules on certain channels makes it a valuable tool in the treatment of numerous disorders.