Modafinil prescribing increased almost 10-fold despite states' opposition to off-label prescribing habits, and reports of associations with hypersensitivity reactions, a research letter reported.
Using a nationally representative sample of ambulatory visits, researchers examined modafinil prescribing habits from 2002 to 2009 for on-label vs. off-label use and specific off-label indications; the specialty of the prescriber; and potential interactions with antidepressants, benzodiazepines and amphetamines.
Results appeared online in a research letter at JAMA Internal Medicine.
Modafinil prescribing increased almost 10-fold, from nearly 58,000 in 2002 to nearly 556,000 in 2009. On-label use increased by less than 3-fold and off-label use increased by more than 15-fold. And, 89% of prescriptions were off-label. Patients with depression were 18% of all prescriptions during the study period, and patients with multiple sclerosis were 12%.
Off-label indications compared to the absence of a diagnosis included multiple sclerosis (odds ratio [OR], 84.6; 95% CI, 50-143), Parkinson's disease (OR, 19.4; 95% CI, 6.7-56.1), chronic fatigue syndrome (OR, 23.4; 95% CI, 4.6-118), depression (OR, 10.8; 95% CI, 6.0-19.5), and attention-deficit/hyperactivity disorder (OR, 5.4; 95% CI, 2.3-12.6).
Patients had higher odds of receiving modafinil relative to primary care physicians and other specialists when treated by psychiatrists (OR, 21.1; 95% CI, 13.2-33.7) and neurologists (OR, 19.7; 95% CI, 12.3-31.5). Patients were not significantly more likely to receive modafinil relative to primary care physicians and other specialists when treated by pulmonologists and otolaryngologists.
Patients were more likely to receive modafinil concurrently with antidepressants (OR, 8.4; 95% CI, 5.4-13.2), benzodiazepines (OR, 5.0; 95% CI, 3.5-10.3), and amphetamines (OR, 8.7; 95%, 4.2-18.6). Altogether, 45% of patients receiving modafinil also took an antidepressant, 15% took a benzodiazepine and 6% took an amphetamine.
Trials used for FDA approval of modafinil excluded patients with depression, multiple sclerosis or those taking benzodiazepine or antidepressants, the researchers noted.
Modafinil prescribing increased even after states settled a lawsuit with the drug's manufacturer in 2008 over off-label promotions, and after there were reports of modafinil-associated hypersensitivity reactions.