Pharmacotherapy of hypertension while breastfeeding

Peripartum cardiomyopathy in a previously asymptomatic carrier of Duchenne muscular dystrophy

A 40 year-old woman presented to hospital with 12h of progressive shortness of breath. She was 11 days postpartum, having delivered a full-term male infant. She was discharged on antibiotics for presumed pneumonia, but represented two days later with NYHA class IV symptoms and in acute decompensated heart failure confirmed on clinical examination and chest X-ray. Echocardiography showed a left ventricular ejection fraction (LVEF) of 20%. She was treated for peripartum cardiomyopathy (PPCM) with angiotensin converting enzyme inhibitors (ACEi), beta-blockers and diuretics with normalisation of her cardiac function within six months. Four years later, her son was diagnosed with Duchenne muscular dystrophy (DMD) and she tested positive as a carrier of the mutant gene. It is unclear whether the DMD carrier state alone is associated with increased susceptibility to PPCM or if this is merely the first expression of cardiomyopathy in a previously asymptomatic carrier.

Pharmacotherapeutic options for the treatment of preeclampsia

PURPOSE

Pharmacotherapeutic options for the treatment of preeclampsia are reviewed.

SUMMARY

Risk factors for the development of preeclampsia include microvascular diseases, such as diabetes mellitus; vascular and connective tissue disorders; hypertension; antiphospholipid antibody syndrome; and nephropathy. Several pathophysiological factors contribute to the development of the preeclamptic state, including vasospasm onset, coagulation system activation, increased inflammatory response, and ischemia. The specific agents used for the treatment of preeclampsia are dependent on a number of factors including symptom severity, maternal or fetal compromise, the progression to eclampsia, gestational period, and cervical status. The diagnosis of preeclampsia beyond the gestation period of 38 weeks requires delivery. The presence of maternal compromise or eclampsia at gestation greater than 20 weeks also necessitates delivery. In cases of chronic or mild hypertension, oral methyldopa may be administered on an outpatient basis. Intravenous hydralazine is a commonly administered arteriolar vasodilator that is effective for hypertensive emergencies associated with pregnancies. The most common adverse effect of hydralazine administration is unpredictable hypotension. Labetalol decreases heart rate and may be preferred because of a lack of reflex tachycardia, hypotension, or increased intracranial pressure. However, the drug of choice for the prevention and control of maternal seizures in patients with severe preeclampsia or eclampsia during the peripartum period is i.v. magnesium sulfate. Therapeutic serum magnesium levels cause cerebral vasodilation, thereby reversing the ischemia produced by cerebral vasospasm during an eclamptic episode. The results of one study indicated that women receiving magnesium sulfate therapy had a 58% lower risk of eclampsia than placebo.

CONCLUSION

Magnesium sulfate remains the drug of choice for the prevention and treatment of preeclampsia. Alternative antihypertensive agents may provide additional benefit in the management of hypertension for preeclamptic patients.

Acute hypertensive emergencies in pregnancy

OBJECTIVE

Obstetrical hypertensive emergencies are life-threatening conditions involving significant risk to both the mother and fetus. Aggressive treatment of the maternal hypertensive state requires an initial consideration of the effect of treatment on the fetus, via changes to the uteroplacental circulation with treatment. The challenge then is to correct blood pressure using appropriate, safe pharmacologic agents to prevent catastrophic maternal consequences, while minimizing acute changes to placental perfusion and any corresponding fetal ill effects. Hypertension in pregnancy may be one manifestation of a multiple-system pathologic process, as is the case in preeclampsia. Blood pressure control, along with delivery, will be the first step in treating the renal, hematologic, hepatic, and cardiac dysfunction that can be seen in preeclampsia.

DESIGN

A review of medications most commonly used for hypertensive emergencies in pregnancy.

CONCLUSIONS

Hypertensive emergencies in pregnancy require prompt evaluation and treatment in an intensive care setting to prevent untoward effects to both the fetus and mother.

Clinical pharmacokinetics of vasodilators. Part II

Stimulating cardiac beta 1-adrenoceptors with oxyfedrine causes dilatation of coronary vessels and positive inotropic effects on the myocardium. beta 1-adrenergic agonists increase coronary blood flow in nonstenotic and stenotic vessels. The main indication for the use of the phosphodiesterase inhibitors pamrinone, mirinone, enoximone and piroximone is acute treatment of severe congestive heart failure. Theophylline is indicated for the treatment of asthma, chronic obstructive pulmonary disease, apnea in preterm infants ans sleep apnea syndrome. Severe arterial occlusive disease associated with atherosclerosis can be beneficially affected by elcosanoids. These drugs must be administered parenterally and have a half-life of only a few minutes. Sublingual or buccal preparations of nitrates are the only prompt method (within 1 or 2 min) of terminating anginal pain, except for biting nifedipine capsules. The short half-life (about 2.5 min) of nitroglycerin (glyceryl trinitrate) makes long term therapy impossible. Tolerance is a problem encountered with longer-acting nitric oxide donors. Knowledge of the pharmacokinetic properties of vasodilating drugs can prevent a too sudden and severe blood pressure decrease in patients with chronic hypertension. In considering the administration of a second dose, or another drug, the time necessary for the initially administered drug to reach maximal efficacy should be taken into account. In hypertensive emergencies urapidil, sodium nitroprusside, nitroglycerin, hydralazine and phentolamine are the drugs of choice, with the addition of beta-blockers during catecholamine crisis or dissecting aortic aneurysm. Childhood hypertension is most often treated with angiotensin-converting enzyme (ACE) inhibitors or calcium antagonists, primarily nifedipine. Because of the teratogenic risk involved with ACE inhibitors, extreme caution must be exercised when prescribing for adolescent females. The propagation of health benefits to breast-fed infants, combined with more women delaying pregnancy until their fourth decade, has entailed an increase in the need for hypertension management during lactation. Low dose hydrochlorothiazide, propranolol, nifedipine and enalapril or captopril do not pose enough of a risk of preclude breastfeeding in this group. The most frequently used antihypertensive agents during pregnancy are methyldopa, labetalol and calcium channel antagonists. Methyldopa and beta-blockers are the drugs of choice for treating mild to moderate hypertension. Prazosin and hydralazine are used to treat moderate to severe hypertension and hydralazine, urapidil or labetalol are used to treat hypertensive emergencies. The use of overly aggressive antihypertensive therapy during pregnancy should be avoided so that adequate uteroplacental blood flow is maintained. Methyldopa is the only drug accepted for use during the first trimester of pregnancy.