The FDA is notifying health care professionals -- specifically, family physicians and OB-Gyns -- that it is requiring the addition of a new boxed warning and contraindication to terbutaline's drug labeling to warn health care professionals about the severe cardiovascular and other risks these products pose for pregnant women. FDA officials also have agreed to reclassify terbutaline from a pregnancy category B drug to a pregnancy category C drug in response to a 2008 citizen petition.
Terbutaline is approved to prevent and treat bronchospasm associated with asthma, bronchitis and emphysema, but the drug also has been used off-label for obstetric purposes, including treating preterm labor and uterine hyperstimulation. In addition, terbutaline has been used for longer periods of time to prevent recurrent preterm labor.
However, new safety information reviewed by the FDA indicates that death and serious adverse reactions, including increased heart rate, transient hyperglycemia, hypokalemia, cardiac arrhythmias, pulmonary edema and myocardial ischemia, have been reported after prolonged administration of oral and injectable terbutaline to pregnant women.
In a Feb. 17 safety alert(www.fda.gov), the FDA acknowledged that administering terbutaline by injection to a pregnant women in urgent obstetrical situations within a hospital setting may be appropriate based on a physician's clinical judgment. However, the agency said terbutaline administered by injection or by continuous infusion pump should not be used beyond 48-72 hours. The agency also emphasized that injectable terbutaline should not be used in the outpatient or home setting.
Furthermore, the FDA said oral terbutaline is contraindicated for the treatment or prevention of preterm labor because it has not been shown to be effective and has safety concerns similar to those associated with the injectable form of the drug.
The agency advised that women who are taking terbutaline for asthma or other medical conditions should talk with their physician if they are pregnant or become pregnant to determine whether use of the drug should be discontinued.
The FDA also encouraged physicians to report adverse events involving terbutaline to the agency's MedWatch program(www.accessdata.fda.gov).