• Metabolism: Diltiazem is metabolized by and acts as an inhibitor of the CYP3A4 enzyme. Half Life: 3.0 - 4.5 hours
• Uses/Sources: For the treatment of hypertension.
• Health Effects: Because of its negative inotropic effect, diltiazem causes a modest decrease in heart muscle contractility and reduces myocardium oxygen consumption. Its negative chronotropic effect results in a modest lowering of heart rate, due to slowing of the sinoatrial node. It results in reduced myocardium oxygen consumption. Because of its negative dromotropic effect, conduction through the AV (atrioventricular) node is slowed, which increases the time needed for each beat. This results in reduced myocardium oxygen consumption. A reflex sympathetic response, caused by the peripheral dilation of vessels and the resulting drop in blood pressure, works to counteract the negative inotropic, chronotropic and dromotropic effects of diltiazem. Undesirable effects include hypotension, bradycardia, dizziness, and flushing. (Wikipedia)
• Symptoms: LD₅₀=740mg/kg (orally in mice)
• Treatment: In the event of overdose or exaggerated response, appropriate supportive measures should be employed in addition to gastrointestinal decontamination. If bradycardia and/or high-degree AV block occurs, administer atropine (0.60 to 1.0 mg). If there is no response to vagal blockage, administer isoproterenol cautiously. Fixed high-degree AV block should be treated with cardiac pacing. In cases of cardiac failure, administer inotropic agents (isoproterenol, dopamine, or dobutamine) and diuretics. If hypotension occurs, use vasopressors (e.g. dopamine or levarterenol bitartrate). (L1712)
• Route of Exposure: Intravenous, Oral. Diltiazem is well absorbed from the gastrointestinal tract but undergoes substantial hepatic first-pass effect.

• Carcinogenicity: No indication of carcinogenicity to humans (not listed by IARC).
• Toxicity: LD₅₀=740mg/kg (orally in mice)

Possibly by deforming the channel, inhibiting ion-control gating mechanisms, and/or interfering with the release of calcium from the sarcoplasmic reticulum, diltiazem, like verapamil, inhibits the influx of extracellular calcium across both the myocardial and vascular smooth muscle cell membranes. The resultant inhibition of the contractile processes of the myocardial smooth muscle cells leads to dilation of the coronary and systemic arteries and improved oxygen delivery to the myocardial tissue.