Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Modafinil has been evaluated for safety in over 3,500 patients, of whom more than 2,000 patients with excessive sleepiness associated with OSA, SWD, and narcolepsy.
Most Common Adverse Reactions
In placebo-controlled clinical trials, the most common adverse reactions (≥ 5%) associated with the use of modafinil more frequently than placebo-treated patients were headache, nausea, nervousness, rhinitis, diarrhea, back pain, anxiety, insomnia, dizziness, and dyspepsia. The adverse reaction profile was similar across these studies.
Table 1 presents the adverse reactions that occurred at a rate of 1% or more and were more frequent in modafinil-treated patients than in placebo-treated patients in the placebo-controlled clinical trials.
Table 1. Adverse Reactions in Pooled Placebo-Controlled TrialsAdverse Reactions that occurred in > 1% of modafinil-treated patients (either 200, 300, or 400 mg once daily) and greater incidence than placebo
in Narcolepsy, OSA, and SWD | Modafinil (%) (n = 934) | Placebo (%) (n = 567) |
|---|
Headache | 34 | 23 |
Nausea | 11 | 3 |
Nervousness | 7 | 3 |
Rhinitis | 7 | 6 |
Back Pain | 6 | 5 |
Diarrhea | 6 | 5 |
Anxiety | 5 | 1 |
Dizziness | 5 | 4 |
Dyspepsia | 5 | 4 |
Insomnia | 5 | 1 |
Anorexia | 4 | 1 |
Dry Mouth | 4 | 2 |
Pharyngitis | 4 | 2 |
Chest Pain | 3 | 1 |
Hypertension | 3 | 1 |
Abnormal Liver Function | 2 | 1 |
Constipation | 2 | 1 |
Depression | 2 | 1 |
Palpitation | 2 | 1 |
Paresthesia | 2 | 0 |
Somnolence | 2 | 1 |
Tachycardia | 2 | 1 |
Vasodilatation | 2 | 0 |
Abnormal Vision | 1 | 0 |
Agitation | 1 | 0 |
Asthma | 1 | 0 |
Chills | 1 | 0 |
Confusion | 1 | 0 |
Dyskinesia | 1 | 0 |
Edema | 1 | 0 |
Emotional Lability | 1 | 0 |
Eosinophilia | 1 | 0 |
Epistaxis | 1 | 0 |
Flatulence | 1 | 0 |
Hyperkinesia | 1 | 0 |
Hypertonia | 1 | 0 |
Mouth Ulceration | 1 | 0 |
Sweating | 1 | 0 |
Taste Perversion | 1 | 0 |
Thirst | 1 | 0 |
Tremor | 1 | 0 |
Urine Abnormality | 1 | 0 |
Vertigo | 1 | 0 |
Dose-Dependent Adverse Reactions
In the placebo-controlled clinical trials which compared doses of 200, 300, and 400 mg/day of modafinil and placebo, the following adverse reactions were dose related: headache and anxiety.
Adverse Reactions Resulting in Discontinuation of Treatment
In placebo-controlled clinical trials, 74 of the 934 patients (8%) who received modafinil discontinued due to an adverse reaction compared to 3% of patients that received placebo. The most frequent reasons for discontinuation that occurred at a higher rate for modafinil than placebo patients were headache (2%), nausea, anxiety, dizziness, insomnia, chest pain, and nervousness (each <1%).
Laboratory Abnormalities
Clinical chemistry, hematology, and urinalysis parameters were monitored in the studies. Mean plasma levels of gamma glutamyltransferase (GGT) and alkaline phosphatase (AP) were found to be higher following administration of modafinil, but not placebo. Few patients, however, had GGT or AP elevations outside of the normal range. Shifts to higher, but not clinically significantly abnormal, GGT and AP values appeared to increase with time in the population treated with modafinil in the placebo-controlled clinical trials. No differences were apparent in alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein, albumin, or total bilirubin.