Off-Label drug use is the prescribing of a medication for a disease or a symptom for which the drug make has never received FDA approval. It is estimated that more than 20% of all prescriptions written are for off-label uses. In some populations, however, that percentage is much higher.
One study found that nearly 80% of children treated in pediatric hospitals were taking at least one off-label medication. Other groups that have a relatively high incidence of off-label drug use are psychiatric patients and pregnant women. Zofran (ondansetron), for example, has never been approved by the FDA for treating expectant mothers with morning sickness.
There are very good policy reasons for making a regulatory distinction between on-label and off-label uses. The FDA approves medications that have been shown to be not only effective, but also safe for a specific use. In order to be proven safe, it is generally required that the drug has to be successfully tested in a series of clinical trials in humans.
It is also important to recognize that the FDA does not regulate how any particular medication is prescribed by doctors after that drug becomes available on the market. Nor does the FDA have the power to do so, since it does not and cannot impose rules on the practice of medicine.
If, however, a drug maker is aware that its drug is commonly prescribed for a disease or condition and that such usage is associated with a clinically significant risk or hazard, then the drug maker has the obligation to provide a warning as to that use.
There are now numerous reports as well as studies showing a statistically significant risk of birth defects such as cleft lip, palate, and heart malformations with the off-label use of Zofran (ondansetron) for morning sickness but the drug makers have failed to provide a specific warning to this effect.