Single Dose and Steady-State Pharmacokinetic Profiles of Nifedipine GITS Tablets in Healthy Elderly and Young Volunteers

Clinical use of nifedipine GITS in the treatment of hypertension: an overview

Given the major role of elevated blood pressure in the pathogenesis of both stroke and coronary heart disease, one of the biggest challenges facing public health authorities and medical practitioners is the control of hypertension worldwide, both in individual patients and at the population level. The prevalence of hypertension increases with age and is nearly 60% in people aged 65 - 74 years. With increasing age, polymorbidity and polypharmacy usually contribute to an increasingly complex approach to manage the respective clinical conditions, including the treatment of hypertension. All subgroups of calcium channel blockers are effective and well-tolerated in lowering blood pressure. They are of demonstrated benefit for the prevention of stroke in elderly patients with systolic hypertension. Calcium channel blockers are particularly recommended for elderly patients with systolic hypertension and for black patients. The nifedipine gastrointestinal therapeutic system (GITS) formulation provides a once-daily dosing regimen with a continuous and slow release of the drug, resulting in a smooth plasma concentration/time profile. The INSIGHT study established that nifedipine GITS decreased mortality and morbidity at the same level as standard diuretic treatment in hypertensive patients with additional risk factors. A subgroup analysis showed that the long-term protective effects of nifedipine GITS extended to hypertensive patients with diabetes mellitus and with previous myocardial infarction. Two substudies of INSIGHT showed that nifedipine slowed the progression of atherosclerosis in carotid arteries (intima-media thickness) and coronary arteries (coronary calcium) as compared to diuretic.

Calcium channel blockers in the management of preterm labor and hypertension in pregnancy

Calcium channel blockers (CCBs) have the ability to inhibit contractility in smooth muscle cells. CCBs have an already established role in the treatment of non-pregnant hypertension and angina pectoris. Some epidemiological studies found an association between the use of CCBs and an increase in cardiovascular mortality, malignancy, and gastrointestinal bleeding. More recent studies with many more patients and a longer follow-up did not find these associations. In obstetrics CCBs have become increasingly popular for the management of preterm labor and pregnancy-induced hypertensive disorders. Meta-analysis shows that use of nifedipine in comparison with betamimetics is associated with a more frequent successful prolongation of pregnancy in case of preterm labor, resulting in significantly fewer admissions of newborns to the neonatal intensive care unit (NICU), and is associated with a lower incidence of respiratory distress syndrome. No adverse fetal side effects in humans have been reported with the use of nifedipine for obstetric indications. Nifedipine is an effective and safe drug to use when tocolytic therapy is indicated for preterm labor. In preeclampsia nifedipine effectively lowers blood pressure and can be a good alternative for (di) hydralazine.

Lack of effect of orlistat on the bioavailability of a single dose of nifedipine extended-release tablets (Procardia XL) in healthy volunteers

Orlistat, a lipase inhibitor, reduces dietary fat absorption, and thus could potentially alter the absorption of some concomitantly administered drugs, such as the nifedipine gastrointestinal therapeutic system (GITS). To assess the effect of orlistat on the bioavailability of nifedipine GITS, a third party-blind, placebo-controlled, randomized, two-way crossover study was performed in 18 healthy volunteers. Each participant received single 60-mg oral doses of nifedipine GITS (Procardia XL; Pfizer Labs, New York, NY) on the fourth day of treatment with 120 mg of orlistat or placebo three times a day for 6 days. The two treatments were separated by a washout period of at least 1 week. Serial blood samples were collected before and at appropriate intervals after each nifedipine dose to determine plasma concentrations of nifedipine. The 90% confidence intervals for the ratio of geometric least-square means for maximum concentration (C(max)) and area under the concentration-time curve (AUCo-t) and for the difference of arithmetic least-square means for time to maximum concentration (t(max)) indicate that the bioavailability of nifedipine was not altered by treatment with orlistat. Therapeutic doses of 120 mg of orlistat three times daily do not significantly alter the bioavailability of a single 60-mg oral dose of nifedipine GITS in healthy volunteers.