The most common adverse events with armodafinil were headache, nausea, dizziness and insomnia. In the trials, 7% of people discontinued the drug because of an adverse event. Headache was the most common reason, but others included psychiatric symptoms such as anxiety, agitation, irritability and depression. There have been cases of suicide in patients taking armodafinil.
In a 12-month open-label trial in 328 patients with narcolepsy, obstructive sleep apnoea or shift work disorder, rare but serious adverse events that were possibly related to armodafinil included chest pain, pulmonary embolism, myocardial infarction and exacerbation of depression.6
Rashes have been reported with armodafinil, including a fatal case of Stevens-Johnson syndrome. The drug should be stopped immediately if a rash develops.
The potential drug interactions with armodafinil are expected to be similar to modafinil. Armodafinil weakly induces cytochrome P450 (CYP) 3A4 so may reduce concentrations of drugs that are metabolised by this enzyme such as hormonal contraceptives, cyclosporin, carbamazepine and midazolam. Armodafinil also inhibits CYP2C19 and may increase concentrations of CYP2C19 substrates such as omeprazole, phenytoin, diazepam, propranolol and clomipramine. More frequent monitoring of INR may be required with co-administered warfarin.
Because of its interaction with hormone contraceptives, women taking armodafinil should use alternative contraception. Armodafinil is contraindicated in pregnancy and not recommended during lactation based on previous animal studies with modafinil showing fetal effects and excretion in breast milk.
Armodafinil significantly improved the ability of patients to stay awake for longer than a placebo. However, this was only by a matter of minutes in sleep latency tests. Although rare, fatalities relating to armodafinil, including from serious skin reactions, have occurred. Psychiatric symptoms can also be a problem. As armodafinil may produce euphoric effects, prescribers should be aware of its potential for abuse.