modafinil: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
modafinil: clinical details
Prescribing considerations
- Confirm narcolepsy after evaluation of excessive sleepiness and exclusion of other causes; initiation should be supervised by an appropriately experienced physician.
- Assess psychiatric history, substance misuse risk, insomnia, cardiovascular disease, hepatic or renal impairment, pregnancy potential and interacting medicines.
- The selected product should not be used in people younger than 18 years.
Contraindications and cautions
- Hypersensitivity to modafinil or an excipient.
- Uncontrolled moderate-to-severe hypertension.
- Cardiac arrhythmias.
Monitoring
- Obtain an ECG before treatment; investigate abnormal findings before considering modafinil.
- Monitor blood pressure and heart rate regularly.
- Review psychiatric symptoms, residual sleepiness, skin reactions, contraception and clinically significant interactions.
- Periodically reassess benefit, adverse effects, misuse and dependence risk.
Clinical pharmacology
Modafinil is a racemic wakefulness-promoting compound with an incompletely defined mechanism. It inhibits dopamine reuptake and, more weakly, noradrenaline uptake. It induces CYP3A4/5 and may inhibit CYP2C19 and CYP2C9 pathways.
Formulation and product differences
- The selected product is an uncoated, score-marked tablet that can be divided into equal halves.
- It contains lactose monohydrate and is essentially sodium-free.
modafinil preparations and strengths
Tablet
Route: Oral
Strengths: 100 mg, 200 mg
modafinil interactions
Modafinil can change the effectiveness or exposure of other medicines. Check prescribed, pharmacy and herbal products before use.
Hormonal contraceptives
May reduce contraceptive effectiveness. An appropriate alternative or additional method is required during treatment and for two months afterwards.
Warfarin
Clearance may decrease, requiring closer clotting-time monitoring when modafinil is started, changed or stopped.
Phenytoin
Exposure may increase; monitor for toxicity and consider checking blood concentrations.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.