For the management of mild to moderate essential hypertension. It may be used alone or concurrently with thiazide-type diuretics.
Isradipine belongs to the dihydropyridine (DHP) class of calcium channel blockers (CCBs), the most widely used class of CCBs. There are at least five different types of calcium channels in <i>Homo sapiens</i>: L-, N-, P/Q-, R- and T-type. CCBs target L-type calcium channels, the major channel in muscle cells that mediates contraction. Similar to other DHP CCBs, isradipine binds directly to inactive calcium channels stabilizing their inactive conformation. Since arterial smooth muscle depolarizations are longer in duration than cardiac muscle depolarizations, inactive channels are more prevalent in smooth muscle cells. Alternative splicing of the alpha-1 subunit of the channel gives isradipine additional arterial selectivity. At therapeutic sub-toxic concentrations, isradipine has little effect on cardiac myocytes and conduction cells.
Symptoms of overdose include lethargy, sinus tachycardia, and transient hypotension. Significant lethality was observed in mice given oral doses of over 200 mg/kg and rabbits given about 50 mg/kg of isradipine. Rats tolerated doses of over 2000 mg/kg without effects on survival.
Isradipine is 90%-95% absorbed and is subject to extensive first-pass metabolism, resulting in a bioavailability of about 15%-24%.
8 hours
Approximately 60% to 65% of an administered dose is excreted in the urine and 25% to 30% in the feces.