Is Procardia XL 60 mg Q Daily Equivalent to 30 mg XL Given Twice Daily?

There is limited evidence regarding the precise BP level at which antihypertensive therapy is indicated during pregnancy for chronic hypertension. Given the limitations of data as well as higher likelihood of outpatient therapy with less frequent blood pressure monitoring, treatment has been suggested in pregnant patients when systolic BP is ≥ 160 mmHg and at a lower diastolic BP threshold of 105 mm Hg , however some providers may initiate therapy at systolic BPs ≥ 150 mmHg.

Antihypertensive therapy has not been shown to improve fetal condition or to prevent preeclampsia. However, such therapy controls acceleration of BP, reduces antepartum hospitalization due to severe hypertension and should help prevent maternal complications from uncontrolled hypertension such as cardiovascular (congestive heart failure and myocardial ischemia), renal (renal injury or failure), or cerebrovascular (ischemic or hemorrhagic stroke) damage.

Drugs such as methyldopa, labetalol, and nifedipine in many occasions are used as first line agents for control of hypertension in pregnancy.

Calcium channel blockers are a class of drugs that have not been extensively studied in pregnant women with chronic hypertension, however they are still considered standard of care for treatment of elevated BPs during pregnancy and after delivery. Small amounts have been shown to cross the placenta, however to date no known association with birth defects have been found with reassuring long term follow-up of babies up to 1.5 years. It is not associated with adverse perinatal outcomes and furthermore, nifedipine does not appear to adversely affect uterine or umbilical blood flow.

Nifedipine is a peripheral arterial vasodilator and an ideal first line antihypertensive agent due to its low maternal side-effect profile. Conventional nifedipine can be started at 10 mg twice daily with a maximum dose of 120 mg/d, but frequently extended release tablets are preferred due to steady blood pressure control with once daily administration. The extended release tablet consists of a semipermeable membrane surrounding an osmotically active drug core and has been designed to provide nifedipine an approximately constant rate over 24h.