From the Guidelines
To convert Lyrica (pregabalin) 50 mg BID to gabapentin, I recommend starting with gabapentin 300 mg three times daily (900 mg total daily dose). This conversion is based on the general principle that pregabalin is approximately 6 times more potent than gabapentin, making 100 mg of pregabalin (50 mg BID) roughly equivalent to 600-900 mg of gabapentin daily 1. Gabapentin should be taken in divided doses due to its shorter half-life and saturable absorption. Some key points to consider when making this conversion include:
- Starting with a dose of 100-300 mg at bedtime or 100-300 mg 3 times daily, and increasing by 100-300 mg 1-7 days as tolerated, with a maximum dose reached after 3-8 weeks of titration plus 2 weeks at maximum dose 1
- The efficacy and tolerability of pregabalin seem to be similar to those of gabapentin; however, pregabalin has linear pharmacokinetics, and dosing is more straightforward 1
- Patients may experience some differences in effect as these medications, while similar, have slightly different pharmacokinetic profiles
- Common side effects for both medications include dizziness, somnolence, and peripheral edema
- When switching, it's best to gradually taper one medication while increasing the other to minimize withdrawal effects and maintain symptom control
- Monitor for efficacy and side effects during the transition period, adjusting the dose as necessary.
From the Research
Conversion of Lyrica to Gabapentin
To convert Lyrica 50 mg BID to gabapentin, we need to consider the pharmacokinetic profiles of both drugs.
- Lyrica (pregabalin) and gabapentin are both α2δ ligands, but they have different potencies and pharmacokinetic profiles 2.
- There is no direct conversion factor available, but a study suggests that gabapentin 900 mg/d is equivalent to pregabalin 150 mg/d, gabapentin 1800 mg/d is equivalent to pregabalin 300 mg/d, and gabapentin 3600 mg/d is equivalent to pregabalin 600 mg/d 3.
- Based on this study, Lyrica 50 mg BID (100 mg/d) could be approximately equivalent to gabapentin 300-600 mg/d, but this is a rough estimate and may vary depending on individual patient factors.
- It's also important to note that gabapentin and pregabalin have different mechanisms of action and may have different efficacy and safety profiles in individual patients 4, 5, 6.
Considerations for Conversion
When converting Lyrica to gabapentin, the following considerations should be taken into account:
- The patient's individual response to gabapentin and pregabalin may vary, and the conversion should be tailored to their specific needs 2.
- Gabapentin may have a lower abuse potential than pregabalin, but it can still be associated with adverse effects and interactions 5, 6.
- The conversion should be done under close medical supervision, and the patient should be monitored for efficacy and safety 3.