Gabapentin
Classification: BATC code: N03AX12
Summary
Controlled studies on differences between men and women in efficacy of gabapentin regarding neuropathic pain or seizures are lacking, but estimates from response in clinical studies do not indicate any significant differences.
The information about pharmacokinetic differences between men and women is conflicting but are not considered to be of clinical significance.
The present evidence concerning differences between men and women is limited and do not motivate differentiation in dosing or treatment.
Additional information
Pharmacokinetics and dosing
It appears that the pharmacokinetic parameters for men and women are similar [1]. One small clinical trial evaluated the effect of sex on the pharmacokinetics of gabapentin in 18 men and 18 women. Following a single 400 mg oral dose gabapentin, Cmax was the only pharmacokinetic parameter that was significantly different between healthy men and women. Cmax was about 25% higher for women than for men, probably due to a smaller volume of distribution in women, as a result of their smaller size. The difference in Cmax values is not considered to be clinically important. The mean value of the apparent volume of distribution was about 17% higher for men than the mean value for women, although it was not statistically significant between sexes. The relations with age for apparent oral clearance and renal clearance were not significantly different in men and women. There was a significant interaction between age and sex for the apparent elimination rate constant, in that there was a significant decline with increasing age for women and no significant relation with age for men. There was a difference in relation between apparent elimination rate constant and age for men and women, but since the relation between the apparent oral clearance and age was similar for men and women, the difference may be due to a sex-related difference in the relation between volume of distribution and age [2]. No sex differentiation in dosing has been recommended by the manufacturer [3].
Effects
No formal analysis on the effect of sex on response to gabapentin in epilepsy has been performed, but estimates of response derived from clinical trials (398 men, 307 women) indicate no important sex differences [1].
Adverse effects
No studies with a clinically relevant sex analysis regarding adverse effects of gabapentin have been found .
Reproductive health issues
Regarding teratogenic aspects, please consult the Drugs and Birth Defects Database (in Swedish, Janusmed fosterpåverkan).
Updated: 2019-02-26
Date of litterature search: 2013-03-12
References
- Gabapentin. DailyMed [www]. US National Library of Medicine. [updated 2012-05-01, cited 2013-03-12]. webplats
- Boyd RA, Türck D, Abel RB, Sedman AJ, Bockbrader HN. Effects of age and gender on single-dose pharmacokinetics of gabapentin. Epilepsia. 1999;40:474-9. PubMed
- Neurontin (gabapentin). Summary of Product Characteristics. Medical Products Agency - Sweden; 2016.
- Läkemedelsstatistik. Stockholm: Socialstyrelsen. 2015 [cited 2016-04-29] länk
Reviewed by: Expertrådet för neurologiska sjukdomar, Ellen Vinge, Lars Lööf
Approved by: Mia von Euler