Why isn't terbutaline approved by the fda for preterm labor?

Terbutaline: To approve a drug for a specific indication, the drug must be studied for that indication. The manufacturer of terbutaline would then present the data from the clinical studies to the fda for approval. The fda would then review the data and make a decision to approve or not to approve the drug for that indication. These steps have not occurred, so the drug is not approved.

Side effect profile.: Terbutaline can block the uterine contractions of the final common pathway leading to preterm labor, however it does nothing to address the etiology of preterm contractions and has significant and potentially life-threatening maternal side effects with tachycardia, hyperglycemia and arrhythmias. There is little evidence that terbutaline (a brochodilator by design) is useful for long-term tocolysis.