Antihypertensives during Pregnancy and lactation - Hypertension is a silent secret disorder that pass unnoticed. Hypertension is generally associated during pregnancy and needs medical attention.Hypertension may be acute and severe caused by preeclampsia. In general drugs should be avoided during first trimester of pregnancy.
The same is true about cardiovascular agents which need to be avoided during this period as they might lead to so many congenital issues, especially from the third to eleventh week of pregnancy.
Literature survey and studies reveal that cardiac drugs used during this sensitive period of pregnancy would lead to problems associated with functional development of the fetus or toxic effects on fetal issues.
The following classes of drugs are frequently used in pregnancy in case need arises and that too after the first trimester of pregnancy.
Antihypertensive agents are required after 20-week pregnancy. The relatively safe agents are Methyldopa, beta adrenergic blockers, hydralazine, labetalol, thiazides and nifedipine.
However, drugs like angiotensin converting enzyme inhibitors, sodium nitroprusside, reserpine, furosemide, diltiazem, verapamil are such cardiovascular agents that are contraindicated.
Methyldopa was the first ever antihypertensive agent used for long term management of hypertension in for more than 30 years. After the introduction of beta blockers in 1990, methyldopa got replaced by these agents because of certain adverse effects such as depression, sedation, postural hypotension produced by methyldopa.
A positive Coombs test pregnancy is also produced by methyldopa. However, it needs to be appreciated that long term consumption of methyldopa does not harm the fetus but rather protects it. Methyldopa is recommended for the treatment of severe hypertension associated with preëclampsia.
Adverse effects of methyldopa include orthostatic hypotension, sedation, dizziness, fatigue, Coombs positive test and depression has been reported in some patients as well.
Beta adrenergic blockers are supposed to somewhat safer agents for controlling hypertension in from the 16 weeks 0 prior to labor. However, blood pressure control just before deliver can be achieved with using methyldopa or hydralazine or combination of atenolol and hydralazine.
Beta blockers unlike methyldopa do not cause orthostatic hypotension, depression. Labetalol, atenolol, pindolol are some the beta blockers used under these circumstances and proved effective. Atenolol has no teratogenic effects as compared to propranolol.
Atenolol can be recommended for long-term controlling of blood pressure during pregnancy as it does not increase the incidence of neonatal respiratory distress syndrome pregnancy.
Hydralazine is another antihypertensive drug used in cases of acute control of especially in the third trimester of pregnancy hypertension. However, the drug is not that secure as compared to methyldopa or beta-adrenergic blockers, if employed for long term
Thiazide diuretics.Generally, diuretics are not employed for control of hypertension during pregnancy and preeclampsia. The situations are associated with reduced plasma volume, so diuretics are not recommended.
Diuretics might lead to various adverse effects like neonatal thrombocytopenia. Calcium channel blockers or antagonists like nifedipine is useful in severe hypertension or preëclampsia.
This antihypertensive agent has been used over a 4-to-6-week period without any adverse effects. Different studies reveal that nifedipine could be employed as an alternative to methyldopa or beta-adrenergic blockers but for short term use only.
Angiotensin converting enzyme inhibitors such as enalapril, Lisinopril, Ramipril are not employed these agents are reported to cause skull defects and are teratogenic in animals. They are contraindicated during pregnancy.
Magnesium sulphate, an inorganic compound, can simply cause a mild or transient lowering of hypertension. However, this very inorganic drug is helpful in controlling seizures associated during preeclampsia.
In addition to pharmacological therapy, nonpharmacological therapy in terms intake of low sodium diet and regular monitoring of blood pressure is mandatory.
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