ATC kod: N03AA02
En studie har visat att män som behandlades med fenobarbital fick en signifikant ökning av prolaktinnivåer, jämfört med friska män.
Fenobarbital kan påverka metabolismen av p-piller och kompletterande antikonceptiv metod bör användas. Under graviditet minskar serumkoncentrationen av fenobarbital med 50-55 % och upp till 70 % av primidonderiverad fenobarbital,.
Several studies have shown that patient’s sex does not significantly improve the estimate of phenobarbital clearance, neither in neonatal, infants or elderly [4, 5]. A review article on clinical pharmacokinetics in pediatric patients concludes that no sex differences on phenobarbital C/D ratios (ratio between plasma concentrations and dose/kg) were found [6].
No studies with a clinically relevant sex analysis regarding the effects of phenobarbital have been found.
A study evaluated prolactin secretion in patients with partial or generalized epilepsy (78 men, 56 women; aged 13-60 years) treated with phenobarbital alone or in combination with either phenytoin or benzodiazepines. An increase in baseline prolactin values was observed in men in all treatment groups, but not in women, compared with healthy controls [7]. Abnormal prolactin levels may be associated with sexual dysfunction [8].
Enzyme-inducing antiepileptic drugs, such as carbamazepine, phenytoin and phenobarbital, may have potentially negative effects on reproductive endocrine function in men and women. These antiepileptic drugs increase concentrations of sex hormone-binding globulin (SHBG) and thereby reducing the concentrations of unbound biologically active androgens [1-3]. This may result in sexual dysfunction.
Concurrent administration of phenobarbital and oral contraceptives may decrease the effect of estradiol. Regarding drug-drug interactions aspects, please consult Janusmed Interactions (in Swedish, Janusmed interaktioner).
In pregnant women, the concentration of phenobarbital is decreased up to 50-55%. The lowered serum concentration is even more pronounced in primidone derived phenobarbital, up to 70% [9]. This may necessitate dose adjustments and therapeutic drug monitoring. Regarding teratogenic aspects, please consult Janusmed Drugs and Birth Defects (in Swedish, Janusmed fosterpåverkan).
Något fler män än kvinnor hämtade ut läkemedel innehållande fenobarbital (ATC-kod N03AA02) på recept i Sverige år 2019, totalt 824 män och 764 kvinnor. Det motsvarar 0,2 respektive 0,2 personer per tusen invånare. Andelen som hämtat ut läkemedel var högst i åldersgruppen 70 år och äldre hos båda könen. Totalt sett var läkemedel innehållande fenobarbital 1,1 gånger vanligare bland män [10].
Uppdaterat: 2020-04-03
Litteratursökningsdatum: 2019-08-28
Faktagranskat av: Mia von Euler, Carl-Olav Stiller, Diana Rydberg
Godkänt av: Karin Schenck-Gustafsson