Dynacirc Pregnancy Warnings
Isradipine has been assigned to pregnancy category C by the FDA. Animal studies have failed to reveal evidence of embryotoxicity at doses which were safe to the mother. There is no evidence of teratogenicity at any dose tested. Animal studies have revealed decreased maternal weight gain at doses up to 150 times the maximum recommended human dose (on a per kg basis), but there were no lasting effects on either the mother or offspring. A controlled study from human pregnancy is available that demonstrates isradipine may be used safely and efficaciously to treat pregnancy-induced hypertension without significantly affecting uterine blood flow. Isradipine should be given during pregnancy only when benefit outweighs risk.
Isradipine crosses the placental barrier, with a fetal to maternal plasma concentration ratio varying between 0.25 and 0.85. There are no known negative effects on neonatal outcome after isradipine 5 mg twice a day.
At least 4 studies (2 using 0.3 mg IV, 1 using 5 mg PO BID, and on using 2.5 mg PO BID) have shown that isradipine can effectively and safely lower blood pressure without altering umbilical and uterine artery blood flow. Doses up to 1.5 mg IV to normotensive women has resulted in a 10% reduction in uterine contractility, significant hypotension in at least one case, and a mean increase in maternal heart rate by 20% to 30%. The various features of the fetal heart rate pattern, as evaluated in a controlled trial by computerized cardiotocography in human pregnancy, were not influenced by isradipine SR 5 mg twice a day in 23 women with preeclampsia.
Because limited data have failed to show that the use of isradipine can effectively lower blood pressure in pregnant patients with hypertension and proteinuria, some experts believe that isradipine is not effective for the treatment of preeclampsia.
See references
Dynacirc Breastfeeding Warnings
There are no data on the excretion of isradipine into human milk. The manufacturer recommends that due to the potential for serious adverse reactions in nursing infants, a decision should be made to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
See references
