Placental vascular responses to nicardipine in the hypertensive ewe
Article Abstract:
Hypertension, or high blood pressure, can be treated with drugs that dilate blood vessels to reduce blood pressure. Nicardipine, a so-called calcium channel blocker, works by preventing calcium from entering the muscle cells lining blood vessels. This causes the blood vessels to relax, thereby lowering blood pressure. When blood vessels constrict, hypertension can develop. Nicardipine is used to treat high blood pressure in pregnancy. Although calcium channel blockers have proven effective in the treatment of hypertension, studies on their effects on the fetus have been limited. It is thought that nicardipine can cause a decrease in the flow of blood through the placenta and a decreased oxygen supply to the fetus. To determine whether nicardipine can reverse the constriction of blood vessels in the placenta in addition to the arterial blood vessels, hypertension was induced in five pregnant ewes. Maternal blood pressure was reduced by nicardipine drug infusion. The vasoconstriction taking place in the placenta, however, was not unexpectedly intensified by nicardipine. This constriction of the placental vessels can severely compromise the fetus by reducing available oxygen. Before nicardipine becomes available for widespread use more studies are warranted.
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1989
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Antagonism of antihypertensive drug therapy in pregnancy by indomethacin?
Article Abstract:
Preeclampsia, an abnormal condition which occurs during pregnancy, is characterized by high blood pressure, protein in the urine and swelling (especially of the face and extremities). Treatment is aimed at reducing high blood pressure with medication. Beta adrenergic receptor-blocking agents, propranolol and pinolol, which have very few adverse effects on both the mother and fetus, are used most often. How propranolol and pinolol lower blood pressure is poorly understood. Indomethacin is an anti-inflammatory drug which can be given to slow premature uterine contractions. Two preeclampsia patients receiving different beta-blocking agents were given indomethacin for the treatment of premature contractions. The blood pressures of both patients increased significantly. Indomethacin works by inhibiting the production of prostaglandins, a hormone-like substance which may dilate blood vessels. Beta-blockers are thought to increase the production of prostaglandins. Therefore, indomethacin may remove the beneficial effects of prostaglandins by decreasing the antihypertensive effect of beta-blocking agents. Indomethacin should not be given to women receiving beta-blocking agents for the reduction of preeclampsia-induced high blood pressure.
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1989
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Fetal vascular responses to maternal nicardipine administration in the hypertensive ewe
Article Abstract:
High blood pressure, or hypertension, can be treated with drugs that dilate blood vessels to reduce blood pressure. Nicardipine, a so-called calcium channel blocker, works by preventing calcium from entering the muscle cells lining blood vessels. This causes the blood vessels to relax, lowering blood pressure. Nicardipine is used to treat high blood pressure in pregnancy. Although calcium channel blockers have proven effective in the treatment of hypertension, studies of their effects on the fetus have been limited. It is thought that the drugs use can cause a decrease in the flow of blood through the placenta and a decreased oxygen supply to the fetus. Pregnant ewes close to delivery time were intentionally made hypertensive and then given a constant blood infusion of nicardipine. Heart and lung functioning was evaluated before, during and after nicardipine infusion. It was concluded that nicardipine did influence the cardiorespiratory functioning of the fetal ewes. The blood flow through the placenta was also compromised. Nicardipine should not be used clinically to treat pregnancy-induced hypertension.
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1989
User Contributions:
Comment about this article or add new information about this topic:
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