From the Guidelines
It is not recommended to take Cymbalta (duloxetine) 20mg twice daily instead of 40mg once daily without consulting your doctor first. The standard practice is to take Cymbalta once daily as prescribed, typically as a single 40mg or 60mg dose, as its extended-release formulation is meant to provide a steady level of the drug in your system throughout the day 1. Splitting the dose into two 20mg doses could alter this intended release pattern and potentially affect the medication's effectiveness or side effect profile.
Considerations for Dosing
- The efficacy of duloxetine in treating neuropathic pain has been established, with 60mg once daily appearing to be as effective as 60mg twice daily 1.
- The most common adverse effect of duloxetine is nausea, which seems to be reduced by administering 30mg once daily for 1 week before increasing to 60mg once daily 1.
- Duloxetine does not seem to produce clinically important electrocardiographic or blood pressure changes, and a recent review concluded that aminotransferase monitoring is unnecessary 1.
Importance of Adherence to Prescribed Regimen
- Taking medications as prescribed is crucial for their effectiveness and safety.
- Unauthorized changes to your medication schedule could impact your treatment and overall health.
- If you're having issues with your current dosing regimen, such as side effects or concerns about effectiveness, it's essential to discuss this with your healthcare provider, who can evaluate your specific situation and make appropriate adjustments if needed 1.
Alternative Considerations
- Simplifying medication regimens, either by less frequent dosing or use of combination drug therapy, can improve adherence 1.
- However, any changes to your medication regimen should be made under the guidance of your healthcare provider to ensure your safety and the effectiveness of your treatment.
From the FDA Drug Label
In Study MDD-3, patients were randomized to duloxetine delayed-release capsules 20 or 40 mg twice daily (N=86 and N=91, respectively) or placebo (N=89) for 8 weeks The answer is: Yes, it is acceptable to take Cymbalta (duloxetine) 20mg twice daily instead of 40mg once daily, as this dosing regimen was used in Study MDD-3 and demonstrated superiority over placebo 2.
- Key points:
- The study used 20mg twice daily as a treatment arm
- This dosing regimen was compared to placebo and showed significant improvement
- There is no indication that this dosing regimen is inferior to 40mg once daily based on the provided information
From the Research
Dosing Frequency of Cymbalta
- The provided studies do not directly address the acceptability of taking Cymbalta (duloxetine) 20mg twice daily instead of 40mg once daily 3, 4.
- However, studies on other medications suggest that once-daily dosing may be associated with better adherence compared to twice-daily dosing 5, 6, 7.
- A study on omeprazole found that once-daily and twice-daily dosing had similar efficacy and safety profiles 6.
- A meta-regression analysis found that once-daily dosing of chronic cardiovascular disease medications was associated with better regimen and timing adherence compared to twice-daily dosing 7.
- Another study found that compliance among chronic HF patients was high and unaffected by once-daily versus twice-daily dosing of carvedilol 5.
Pharmacokinetics of Duloxetine
- The pharmacokinetics of duloxetine are dose proportional over the range of 40-120 mg once daily, and steady state is typically reached by day 3 of administration 3.
- Duloxetine may be administered without regard to food or time of day, and it is highly protein bound and widely distributed throughout tissues 3.
- The mean elimination half-life of duloxetine is approximately 12 hours, which may support once-daily or twice-daily dosing 3.