Bepridil

Uses

For the treatment of hypertension, and chronic stable angina (classic effort-associated angina).

How Bepridil works

Bepridil has inhibitory effects on both the slow calcium (L-type) and fast sodium inward currents in myocardial and vascular smooth muscle, interferes with calcium binding to calmodulin, and blocks both voltage and receptor operated calcium channels. Bepridil inhibits the transmembrane influx of calcium ions into cardiac and vascular smooth muscle. This has been demonstrated in isolated myocardial and vascular smooth muscle preparations in which both the slope of the calcium dose response curve and the maximum calcium-induced inotropic response were significantly reduced by bepridil. In cardiac myocytes in vitro, bepridil was shown to be tightly bound to actin. Bepridil regularly reduces heart rate and arterial pressure at rest and at a given level of exercise by dilating peripheral arterioles and reducing total peripheral resistance (afterload) against which the heart works.

Toxicity

There has been one experience with overdosage in which a patient inadvertently took a single dose of 1600 mg of bepridil. The patient was observed for 72 hours in intensive care, but no significant adverse experiences were noted.

Food Interaction

• Avoid alcohol. Alcohol can potentiate hypotension and dizziness when taken with this drug.
• Take with food. Food reduces nausea.

[Moderate] MONITOR: Grapefruit juice may increase the plasma concentrations of orally administered drugs that are substrates of the CYP450 3A4 isoenzyme.

The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit.

Because grapefruit juice inhibits primarily intestinal rather than hepatic CYP450 3A4, the magnitude of interaction is greatest for those drugs that undergo significant presystemic metabolism by CYP450 3A4 (i.e., drugs with low oral bioavailability).

In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands.

Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition.

Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Patients who regularly consume grapefruit or grapefruit juice should be monitored for adverse effects and altered plasma concentrations of drugs that undergo significant presystemic metabolism by CYP450 3A4.

Grapefruit and grapefruit juice should be avoided if an interaction is suspected.

Orange juice is not expected to interact with these drugs.

Bepridil Alcohol interaction

[Moderate]

Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation.

Coadministration with antihypertensives and other hypotensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

Caution and close monitoring for development of hypotension is advised during coadministration of these agents.

Some authorities recommend avoiding alcohol in patients receiving vasodilating antihypertensive drugs.

Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia.

Bepridil multivitamins interaction

[Moderate] Calcium-containing products may decrease the effectiveness of calcium channel blockers by saturating calcium channels with calcium.

Calcium chloride has been used to manage acute severe verapamil toxicity.

Management consists of monitoring the effectiveness of calcium channel blocker therapy during coadministration with calcium products.

Bepridil Drug Interaction

Moderate: aspirin, aspirin, alprazolam, alprazolam, diphenhydramine, diphenhydramine, metoprolol, metoprololUnknown: acetaminophen, acetaminophen, pseudoephedrine / triprolidine, pseudoephedrine / triprolidine, trolamine salicylate topical, trolamine salicylate topical, ipratropium, ipratropium, amoxicillin / clavulanate, amoxicillin / clavulanate, dicyclomine, dicyclomine

Bepridil Disease Interaction

Major: agranulocytosis, arrhythmias, CHF, electrolyte imbalance/hypokalemia, MI, bradyarrhythmia/AV block, cardiogenic shock/hypotension, liver disease

Elimination Route

Rapidly and completely absorbed after oral administration.

Half Life

24-50 hours

Innovators Monograph

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