Is a split dose of Sunosi (solriamfetol) such as 150 mg in the morning and an additional 75 mg four hours later used for narcolepsy?

Split Dosing of Sunosi is NOT FDA-Approved for Narcolepsy

Split dosing of Sunosi (solriamfetol) such as 150 mg in the morning plus 75 mg four hours later is not an FDA-approved regimen and exceeds the maximum recommended daily dose of 150 mg for narcolepsy. The FDA label explicitly states that dosages above 150 mg daily do not provide increased effectiveness sufficient to outweigh dose-related adverse reactions 1.

FDA-Approved Dosing for Narcolepsy

According to the FDA prescribing information 1:

• Starting dose: 75 mg once daily upon awakening
• Dose range: 75-150 mg once daily
• Maximum dose: 150 mg once daily
• Titration: May double the dose at intervals of at least 3 days based on efficacy and tolerability
• Administration: Single daily dose upon awakening, with or without food
• Timing restriction: Avoid taking within 9 hours of planned bedtime

The proposed regimen of 150 mg + 75 mg (total 225 mg daily) would represent a 50% increase over the maximum approved dose.

Why Higher Doses Are Not Recommended

The FDA label specifically warns that dosages above 150 mg daily do not confer increased effectiveness sufficient to outweigh dose-related adverse reactions 1. This is a critical safety consideration given that:

Cardiovascular Risks

Solriamfetol increases blood pressure and heart rate in a dose-dependent fashion 1. The drug carries warnings about:

• Increased risk of major adverse cardiovascular events (MACE)
• Stroke, heart attack, and cardiovascular death
• Particular concern in patients with pre-existing hypertension, cardiovascular disease, diabetes, and high BMI—conditions common in narcolepsy patients

Evidence Quality

The 2021 American Academy of Sleep Medicine guidelines provide a STRONG recommendation for solriamfetol use in narcolepsy based on high-quality evidence from 3 RCTs 2. However, these trials evaluated standard FDA-approved dosing, not split or supramaximal dosing regimens.

Clinical Practice Insights

Real-world data from the START study 3 examining 70 patients with narcolepsy showed:

• 86% initiated at 75 mg daily
• 76% were stable at 150 mg daily (the maximum approved dose)
• Most patients (67%) required only one dose adjustment
• Median time to stable dose was 14 days

No evidence supports split dosing or exceeding 150 mg daily in clinical practice.

Common Pitfalls to Avoid

• Do not split the daily dose: The pharmacokinetics and clinical trials support once-daily dosing only
• Do not exceed 150 mg daily: The risk-benefit ratio becomes unfavorable above this threshold
• Monitor blood pressure: Ensure hypertension is controlled before initiating and monitor regularly during treatment
• Respect the 9-hour rule: Taking solriamfetol too late causes insomnia, which is already a common adverse effect (reported in clinical trials) 2

Alternative Approaches if 150 mg is Insufficient

If a patient with narcolepsy has inadequate response to 150 mg daily solriamfetol:

1. Verify adherence and timing: Confirm the patient takes it upon awakening
2. Optimize other narcolepsy treatments: Consider adding or optimizing sodium oxybate for comprehensive narcolepsy management (which also has a STRONG recommendation with moderate-quality evidence) 2
3. Consider switching agents: Alternatives include modafinil, armodafinil, or traditional stimulants per AASM guidelines 2
4. Combination therapy: The START study found 29% of patients used solriamfetol as add-on therapy to existing medications 3

The proposed split-dose regimen lacks evidence, exceeds safety thresholds, and contradicts FDA labeling.