How to Order 90mg of Duloxetine Extended Release
To obtain 90mg of duloxetine ER, prescribe three 30mg capsules taken together once daily, as duloxetine is not manufactured in a 90mg strength. 1
Available Formulations and Dosing Strategy
Duloxetine is commercially available in the following capsule strengths: 20mg, 30mg, and 60mg. 1 Since 90mg is not a standard manufactured dose, you must combine available strengths to achieve this total daily dose.
Practical Prescribing Options for 90mg Daily:
- Option 1 (Preferred): Prescribe duloxetine 60mg + 30mg taken together once daily in the morning 1
- Option 2: Prescribe three 30mg capsules taken together once daily 1
The maximum FDA-approved dose is 120mg daily (60mg twice daily), so 90mg falls within the approved dosing range. 1
Clinical Context for 90mg Dosing
The 90mg dose represents an intermediate step between the standard 60mg and maximum 120mg daily doses:
- For diabetic peripheral neuropathy: Standard dosing is 60-120mg daily, with approximately 50% of patients achieving at least 50% pain reduction at 12 weeks on these doses 2, 1
- For generalized anxiety disorder: Doses of 60-120mg once daily showed efficacy in multicenter trials 2, 3
- For fibromyalgia and chronic pain: 60mg once daily is typically the target dose, though some patients may benefit from higher doses up to 120mg 1, 4
Titration Considerations
If initiating duloxetine and planning to reach 90mg, follow this evidence-based approach:
- Start at 30mg once daily for one week to minimize adverse effects, particularly nausea 1, 5
- Increase to 60mg once daily (the standard therapeutic dose) 1
- If response is suboptimal after 7 weeks at 60mg, consider increasing to 90mg before reaching the maximum 120mg 1
- Taking duloxetine with food, especially when starting at higher doses, significantly reduces nausea and improves tolerability 5
Important Prescribing Caveats
- Duloxetine is not a controlled substance and does not appear in DEA schedules I-V, so standard prescription protocols apply 1
- Common adverse effects include nausea (most prominent in first week), dry mouth, headache, constipation, and dizziness 2, 1
- Monitor blood pressure, as duloxetine can increase systolic and diastolic BP and heart rate 1
- Avoid in patients with creatinine clearance <30 mL/min or hepatic impairment 6
- When discontinuing, taper the dose to prevent withdrawal symptoms, especially after treatment longer than 3 weeks 1