Changes to FDA Pregnancy and Lactation Labeling

On December 3, 2014, the FDA issued a new rule revising the current regulations pertaining to the pregnancy, labor and delivery, and nursing mother sections of the prescribing information for prescription drugs and biologic products. Initiation of this amendment was prompted by the FDA’s goal to provide women and their healthcare providers with sufficient information when deciding which medications to prescribe in pregnant and breastfeeding patients.

^{Why the change?}

Recent data indicate that about 90% of pregnant women take at least one medication and 70% take one or more prescription drugs, potentially putting the fetus at high risk for drug-induced developmental abnormalities. Many pregnant women may also be on medications to control chronic disease states such as hypertension or to manage acute conditions developed during pregnancy such as gestational diabetes.  It is also necessary to consider that about half of all pregnancies are unexpected, leading to unintended drug exposure.

Heparin-induced hyperkalemia

Heparin and low molecular weight heparins (LMWH) are some of the many medications that have been identified to cause hyperkalemia.  When looking for more information about this in the prescribing information, Lexicomp, and Micromedex, there is a paucity of information.  

The prescribing information does not mention potassium at all, merely stating that suppression of aldosterone synthesis has been reported, whereas the other sources give rates from <1% to 8%.  The following will discuss the typical time course and extent of changes in potassium identified in some studies, the proposed mechanism for these effects, and risk factors.