Is Nicardipine (a calcium channel blocker) safe during pregnancy?

From the Guidelines

Nicardipine should not be used as a first-line antihypertensive medication during pregnancy due to its potential risks to the fetus and the availability of safer alternatives. According to the most recent evidence from the study published in Circulation in 2025 1, first-line antihypertensive medications during pregnancy include extended-release nifedipine and labetalol, which have more robust safety and efficacy data. The use of nicardipine in pregnancy is classified as FDA pregnancy category C, which means it should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. While there are no adequate well-controlled studies in pregnant women, animal studies have shown adverse effects on the fetus at doses several times the maximum recommended human dose. If blood pressure control is needed during pregnancy, medications with better safety profiles such as labetalol, nifedipine, or methyldopa are generally preferred as first-line options. Some key points to consider when managing hypertension in pregnancy include:

• The potential risks and benefits of each medication
• The importance of close monitoring of maternal blood pressure and fetal wellbeing
• The need for careful consideration of the timing of delivery based on fetal wellbeing, gestational age, and type of hypertensive disorder. In specific situations where other medications have failed or are contraindicated, nicardipine may be considered, but this decision should be made after careful consideration of risks and benefits by the healthcare provider, as suggested by the European Heart Journal study in 2020 1. Any pregnant woman currently taking nicardipine should not discontinue it without consulting her healthcare provider to determine an appropriate alternative treatment plan. The concern with nicardipine in pregnancy relates to potential effects on uterine blood flow and fetal development, though human data is limited. Overall, the goal of managing hypertension in pregnancy is to balance the risks and benefits of treatment to optimize outcomes for both the mother and the fetus.

From the FDA Drug Label

Nicardipine was embryocidal when administered orally to pregnant Japanese White rabbits, during organogenesis, at 150 mg/kg/day (a dose associated with marked body weight gain suppression in the treated doe) but not at 50 mg/kg/day (25 times the maximum recommended antianginal or antihypertensive dose in man) No adverse effects on the fetus were observed when New Zealand albino rabbits were treated, during organogenesis, with up to 100 mg nicardipine/kg/day (a dose associated with significant mortality in the treated doe). In pregnant rats administered nicardipine orally at up to 100 mg/kg/day (50 times the maximum recommended human dose) there was no evidence of embryolethality or teratogenicity However, dystocia, reduced birth weights, reduced neonatal survival, and reduced neonatal weight gain were noted. There are no adequate and well-controlled studies in pregnant women. nicardipine hydrochloride capsules should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus

Pregnancy Category: The FDA drug label does not explicitly state the pregnancy category of Nicardipine. However, based on the available information, it can be inferred that Nicardipine should be used with caution during pregnancy.

• Key points:
  • Embryocidal effects were observed in Japanese White rabbits at high doses.
  • No adverse effects were observed in New Zealand albino rabbits at lower doses.
  • No embryolethality or teratogenicity was observed in rats, but other adverse effects were noted.
  • There are no adequate and well-controlled studies in pregnant women.
• Clinical decision: Nicardipine hydrochloride capsules should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus 2.

From the Research

Nicardipine Safety in Pregnancy

• Nicardipine is considered safe for use in pregnancy, particularly for treating severe hypertension 3, 4, 5.
• Studies have shown that nicardipine can effectively reduce blood pressure in pregnant women with severe hypertension, with a high success rate and acceptable safety profile 3, 4.
• The use of nicardipine in pregnancy has been associated with minimal side effects, including temporary low diastolic blood pressure and headaches 3, 5.
• Nicardipine has been compared to other antihypertensive medications, such as labetalol and methyldopa, and has been found to be a viable option for treating severe hypertension in pregnancy 6.

Efficacy of Nicardipine in Pregnancy

• Nicardipine has been shown to be effective in reducing blood pressure in pregnant women with severe hypertension, with a significant reduction in systolic and diastolic blood pressure 3, 4, 5.
• The medication has been found to be effective in achieving target blood pressure within a short period, typically within 1-2 hours 3, 4.
• Nicardipine has been used in various clinical settings, including neurosurgery, cardiothoracic surgery, and internal medicine, and has been found to be safe and effective in these settings 7.

Comparison with Other Antihypertensive Medications

• Nicardipine has been compared to other antihypertensive medications, such as labetalol and methyldopa, and has been found to be a viable option for treating severe hypertension in pregnancy 6.
• The choice of antihypertensive medication in pregnancy should be based on individual patient factors, including the severity of hypertension and the presence of any underlying medical conditions 4, 6.