Skip to main content

Osmolex ER Dosage

Dosage form: tablet, extended release
Drug class: Dopaminergic antiparkinsonism agents

Medically reviewed by Last updated on Feb 8, 2024.

Dosage Information

The recommended initial dosage of OSMOLEX ER is 129 mg administered orally once daily in the morning. The dosage may be increased in weekly intervals to a maximum daily dose of 322 mg (administered as a 129 mg and 193 mg tablet), taken in the morning.

OSMOLEX ER is not interchangeable with other amantadine immediate- or extended-release products.

For patients unable to tolerate more than 100 mg per day of immediate-release amantadine, there is no equivalent dose or dosing regimen of OSMOLEX ER.

Administration Information

OSMOLEX ER should be swallowed whole. Do not chew, crush, or divide tablets. OSMOLEX ER can be administered without regard to food.

Dosing in Patients with Renal Impairment

There are no modifications for the recommended initial and maximum dosage in patients with renal impairment; however, modifications are recommended for the titration interval and frequency of dosing in patients with moderate and severe renal impairment (see Table 1).

Table 1: Recommended Titration and Frequency of OSMOLEX ER Dosing in Patients with Renal Impairment
Renal Function/Estimated GFR (mL/min/1.73 m 2) * Minimum Titration Interval Frequency of Dosing Regimen
Mild renal impairment (60 to 89) Increase every week One dose every 24 hours
Moderate renal impairment (30 to 59) Increase every 3 weeks One dose every 48 hours
Severe renal impairment (15 to 29) Increase every 4 weeks One dose every 96 hours
End-Stage Renal Disease (below 15) Contraindicated
* estimated by Modification of Diet in Renal Disease (MDRD) method

Monitor patients with renal impairment for change in renal function, especially in those with severe renal impairment receiving the maximum daily dosage of 322 mg [see Use in Specific Populations (8.6)] .

Discontinuation, Dose Reduction, and Missed Dose

OSMOLEX ER should not be discontinued abruptly. The dose should be reduced gradually from higher doses to 129 mg daily for 1 to 2 weeks before discontinuing [see Warnings and Precautions (5.5)] .

If a dose of OSMOLEX ER is missed, the next dose should be taken as scheduled.

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.