Drug Interaction Report

In single-dose pharmacokinetic studies, healthy volunteers given modafinil (200 mg) with dextroamphetamine (10 mg) or methylphenidate (40 mg) exhibited a delay in the absorption of modafinil by approximately 1 hour. The mechanism of interaction is unknown. No other alterations in the pharmacokinetics of any of the drugs were observed. Although not studied, the interaction is likely to also occur with the various prodrug, racemic, and enantiomeric formulations of these drugs (e.g., amphetamine, lisdexamfetamine, dexmethylphenidate, armodafinil).

Administration with food may delay the absorption of modafinil (the racemate) and armodafinil (the R-enantiomer) without significantly affecting their overall bioavailability. According to the product labeling, modafinil's absorption may be delayed by approximately one hour if taken with food. Similarly, the time to reach peak plasma concentration (Tmax) of armodafinil may be delayed by approximately 2 to 4 hours in the fed state.

The recommended maximum number of medicines in the 'stimulants' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'stimulants' category:

• armodafinil
• Focalin XR (dexmethylphenidate)

Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.

The recommended maximum number of medicines in the 'cerebral stimulants' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'cerebral stimulants' category:

• armodafinil
• Focalin XR (dexmethylphenidate)

Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.