The more elevated your blood pressure and the more severe your preeclampsia, the higher your risk of complications such as stroke. Anti-hypertensive medicines may regulate your blood pressure and prevent such complications.
Several medications are prescribed for pregnant women with high blood pressure due to preeclampsia. These agents lower blood pressure and protect against complications, and are mainly available in pill form. Anti-hypertensive medications are initiated for systolic blood pressures above 160 and diastolic blood pressures between 105 and 110. However, if your blood pressure is over 180/120, you may require intravenous medication to lower it.
- Methyldopa (for example, Aldomet) has been studied extensively and is recommended by many experts as the first-line oral anti-hypertensive medication in pregnancy. It is a centrally acting, alpha-adrenergic agonist-it affects the central nervous system and inhibits the medulla oblongata in the brain from sending signals for the blood vessels to constrict (which would raise blood pressure). This is referred to as vasoconstriction. The daily dosage is 500 milligrams to 4 grams, divided among two or four doses. Methyldopa can also be given intravenously, if needed.
- Labetalol (for example, Normodyne or Trandate) is another first-line oral anti-hypertensive medication that blocks blood vessel receptors which cause vasoconstriction. It is safe to use during pregnancy. The usual dose is 100 mg, twice a day and may be increased weekly to a total of 800mg, three times a day. Labetalol is safe for intravenous use as well.
- Nifedipine (Procardia) is a calcium-channel blocker-it relaxes blood vessels and reduces the heart rate. Several reports suggest that nifedipine is safe during pregnancy, although it is not used as extensively as methyldopa and labetalol. When used during pregnancy, the long-acting formula (Procardia XL, Adalat CC) is preferred. This agent is taken just once a day, usually 30 mg. If necessary, the dose may be increased to 90 mg daily. (Nifedipine is not prescribed if you are receiving magnesium sulfate therapy. The combination of these drugs may cause excessively low blood pressures and may alter neuromuscular activity. Using nifedipine sublingually-allowing it to dissolve under your tongue-is also not recommended as it can cause blood pressure levels to fluctuate unpredictably.)
- Atenolol (Tenormin) and clonidine (Catapres) are other possible options, but they have not been used by pregnant women as extensively as the medications listed above.
- Hydralazine (Apresoline) is another drug that can be given orally or intravenously to control hypertension in pregnancy. It is primarily used as an intravenous agent to control elevated blood pressures.
Medicines to Avoid During Pregnancy
Angiotensin-converting enzyme (ACE) inhibitors -drugs such as enalapril (Vasotec) and captopril (Capoten), which interfere with the body's production of a chemical that causes the arteries to constrict-during pregnancy are associated with birth defects such as fetal hypocalvaria (small fetal head), renal defects, anuria (absence of urine), and fetal and neonatal death. These agents are absolutely not advised in pregnancy, especially in the second and third trimesters.
With few exceptions, diuretics such as furosemide (Lasix) and hydrochlorothiazide (HCTZ or Microzide), which lower blood pressure by clearing extra fluid and salt from the body and dilating blood vessels, should be avoided during pregnancy.
Finally, propanolol (for example, Inderal)-a beta-blocker, which lowers blood pressure by reducing heart rate and the amount of blood pumped by the heart-has been associated with birth defects, such as fetal bradycardia (slow heartbeat), growth retardation, and neonatal hypoglycemia.
Controlling high blood pressure is an important part of the treatment for preeclampsia. The only way to cure the disorder if you are pregnant is to delivery your baby. Depending on the severity of your symptoms and how near to term you are, your doctor may decide that it is necessary to deliver your baby right away.