High blood pressure (hypertension) is one of the most common complications of pregnancy. How safe are the antihypertensives?
Methyl-dopa (Aldomet®) is one of the most common antihypertensives used in pregnancy. It has been around for many years. It is known to be safe.
Other calcium channel blockers include Nimodipine (Nimotop®), Felodipine (Plendil®), Amlodipine (Istin®), Diltiazem (Tildiem®) and several others.
A group of popular anti-hypertensives are the ones known as "ACE-inhibitors". What about these in pregnancy?
Yes, ACE-inhibitors such as captopril (Capoten®), enalapril (Innovace®), Cilazapril (Vascace®), lisinopril (Carace®, Zestril®), quinapril (Accupro®) and a few others are very effective anti-hypertensives. They are not used in pregnancy. In fact, any woman taking these who is planning to conceive should be weaned off them and put on something else (such as a beta blocker or methyl-dopa).
What about anti-hypertensive medications which contain diuretics. Can these preparations be used in pregnancy?
There is no simple answer to this question. However, if hypertension is part of the syndrome known as pre-eclampsia, diuretics (alone or in combination) should not be used. This is because their "drying" effect could worsen the poor blood supply to the baby inherent in this condition.
Chronic hypertension is not associated with this problem. However, pre-eclampsia could superimpose itself on simple chronic hypertension. For this reason, it is probably best to avoid diuretics in pregnancy altogether, especially if their use is to be long-term. As regards their effect on the fetus, the common diuretics (bendrofluazide and frusemide) are probably safe, as there is no evidence of direct ill-effects on the baby.
In summary therefore, diuretics, alone or in combination, should not be used in pre-eclampsia as they can potentially do more harm than good. They can probably be used safely in uncomplicated chronic hypertension but better alternatives are usually available.
Does the above mean, where strongly indicated, diuretics can be used in pregnancy?
Yes. If the pregnant woman is in heart failure or has lung oedema (water on the lungs), diuretics are indispensable and should be used.