Prescriber Update Articles

Modafinil safety review – a wake up call

Web site: December 2011
Prescriber Update 2011;32(4): 33

Medsafe has recently completed a safety review of modafinil, a medicine that promotes wakefulness but the precise mechanism of action remains unclear.

Medsafe has concluded that the benefits of treatment outweigh the potential risks when used:

To improve wakefulness in patients with excessive daytime sleepiness (EDS) associated with narcolepsy.
To treat EDS associated with moderate to severe chronic shift work sleep disorder (SWSD) where non-pharmacological interventions are unsuccessful or inappropriate.
As an adjunct to continuous positive airways pressure (CPAP) to treat excessive daytime sleepiness in patients with obstructive sleep apnoea hypopnoea syndrome (OSAHS).

The Australian medicines regulator (TGA) has also recently confirmed that the balance of risks and benefits of modafinil is positive when used for these indications.¹

The Modavigil (modafinil) datasheet is being updated to include more information about the risk of multi-organ hypersensitivity reactions, serious skin reactions, psychiatric disorders, cardiovascular disease, and the potential for dependence.

Prescribers are encouraged to familiarise themselves with the complete prescribing information for modafinil available on the Medsafe website at www.medsafe.govt.nz .

Key messages for healthcare professionals:

Modafinil treatment should be initiated and supervised by physicians with experience in sleep disorders such as neurologists or respiratory specialists.
Modafinil is contraindicated for use in pregnancy and is not approved for use in children or adolescents for any indication.
The development of skin and hypersensitivity reactions, central nervous system, psychiatric and cardiovascular system adverse reactions appears to be related to higher doses of modafinil. Therefore, modafinil should always be started and maintained at the lowest possible dose.
The effectiveness of oral contraceptives may be impaired in patients receiving modafinil due to the induction of the CYP 3A4 enzyme system.
PHARMAC currently subsidises modafinil (under special authority criteria) for the treatment of EDS associated with narcolepsy only.²

References

TGA (2011). Modafinil (Modavigil) – safety update. Medicines Safety Update Volume 2, Number 5, October 2011. Available at http://www.australianprescriber.com/magazine/34/5/148/51
PHARMAC (2011). Application for subsidy by special authority. Available at http://www.pharmac.govt. nz/2011/11/01/SA1126.pdf

INFORMATION FOR HEALTH PROFESSIONALS

Prescriber Update Articles

Modafinil safety review – a wake up call