Provigil Autoimmune Disease Considerations

Is modafinil approved for any autoimmune condition?

No. The three indications in the Provigil label are excessive sleepiness from narcolepsy, obstructive sleep apnea and shift work disorder in adults [3]. Fatigue in multiple sclerosis, lupus or any other autoimmune disease is an off-label use [3]. Modafinil is a Schedule IV controlled substance and is available by prescription only [3].

What the trials show for multiple sclerosis fatigue

The 2002 single-blind study found lower fatigue scores after 200 mg a day than during its placebo run-in [1]. A later randomized, double-blind crossover trial found no benefit over placebo on its primary fatigue measure [2].

The 2002 phase 2 study enrolled 72 people with MS and fatigue at two centres. Participants stayed blinded to the regimen while safety was judged by unblinded investigators: placebo for weeks 1 to 2, modafinil 200 mg a day for weeks 3 to 4, modafinil 400 mg a day for weeks 5 to 6, then placebo again for weeks 7 to 9. At 200 mg a day, mean Fatigue Severity Scale score was 4.7 versus 5.5 with placebo (p<0.001), the Modified Fatigue Impact Scale was 37.7 versus 44.7 (p<0.001), and the visual analogue fatigue scale was 5.4 versus 4.5 (p=0.003). The 400 mg dose did not significantly improve fatigue scores compared with the placebo run-in. Headache, nausea and asthenia were the most common adverse events, and 65 of the 72 patients completed the study [1].

The 2021 trial was randomised, double-blind, placebo-controlled and used a four-period crossover. It enrolled 141 people with MS fatigue, 136 of whom entered the primary analysis, and compared modafinil up to 100 mg twice daily with amantadine, methylphenidate and placebo. On the Modified Fatigue Impact Scale at the highest tolerated dose, scores were 40.6 with placebo, 41.3 with amantadine, 39.0 with modafinil and 38.6 with methylphenidate (p=0.20 overall). No drug separated from placebo on the primary outcome [2].

The two studies used different designs and different dose ranges, and only the smaller, earlier, single-blind one found improvement, and that was against a placebo run-in.

Does modafinil interact with immunosuppressants?

Yes, with at least one that the label names. Modafinil induces CYP3A4/5, and the label says clearance of CYP3A4/5 substrates may be increased, lowering systemic exposure and possibly requiring dose adjustment; it names steroidal contraceptives, cyclosporine, midazolam and triazolam [3]. For cyclosporine, blood levels may be reduced, and monitoring of circulating cyclosporine concentrations with appropriate dose adjustment should be considered [3].

The label also covers enzyme inhibition in the other direction. Elimination of CYP2C19 substrates such as phenytoin, diazepam, propranolol, omeprazole and clomipramine may be prolonged, raising exposure, and dose adjustment may be needed [3]. In people deficient in CYP2D6, tricyclic antidepressants and SSRIs may rise [3]. More frequent prothrombin time/INR monitoring should be considered when modafinil is given with warfarin [3], and caution applies with MAO inhibitors [3].

What does the label say about serious rash?

Serious rash, including Stevens-Johnson syndrome, toxic epidermal necrolysis and DRESS, has been reported in worldwide postmarketing experience, and the reporting rate of TEN and SJS with modafinil exceeds the background rate of 1 to 2 cases per million person-years [3]. Nearly all cases occurred within 1 to 5 weeks of starting, though isolated cases appeared after about 3 months [3]. The label states that no factors are known to predict the risk of occurrence or the severity of rash [3]. It directs that the drug be discontinued at the first sign of rash unless the rash is clearly not drug-related, and notes that stopping may not prevent a rash from becoming life-threatening or disfiguring [3].

In pediatric trials (under age 17), rash led to discontinuation in about 0.8% (13 of 1,585), including one possible SJS and one apparent multi-organ hypersensitivity reaction, versus none among 380 placebo patients; modafinil is not approved for children [3].

Multi-organ hypersensitivity, with fever and rash plus organ involvement such as myocarditis, hepatitis or eosinophilia, has occurred at a median of 13 days (range 4 to 33) after starting, with at least one fatality in postmarketing reports [3]. The label says angioedema and hypersensitivity were seen in patients treated with armodafinil, and angioedema has been reported postmarketing with modafinil; signs include swelling of the face, eyes, lips, tongue or larynx, difficulty swallowing or breathing, and hoarseness [3].

Provigil has no boxed warning; these reactions sit in Warnings and Precautions [3].

Psychiatric and cardiovascular warnings

In adult Provigil trials, treatment discontinuation for anxiety (1%), nervousness (1%) and, in under 1%, insomnia, confusion, agitation and depression was reported more often than with placebo [3]. Postmarketing reports include mania, delusions, hallucinations, suicidal ideation and aggression, some requiring hospitalization, many in people with a prior psychiatric history; the label says to use caution in patients with a history of psychosis, depression or mania [3].

On the cardiovascular side, a larger share of Provigil patients needed new or increased antihypertensive medicine (2.4% versus 0.7% with placebo; 3.4% versus 1.1% in the OSA studies), and use is not recommended in left ventricular hypertrophy or in mitral valve prolapse syndrome previously triggered by CNS stimulants [3].

Dosing in the label

For narcolepsy or obstructive sleep apnea, 200 mg once a day in the morning; for shift work disorder, 200 mg about 1 hour before the shift starts. For approved uses, the Provigil label recommends reducing the dose by half in severe hepatic impairment and considering lower doses with closer monitoring in older adults [3]. Doses up to 400 mg a day have been well tolerated, but there is no consistent evidence that 400 mg adds benefit over 200 mg [3].