Can oxcarbazepine (Trileptal) cause decreased libido, erectile dysfunction, or vaginal dryness, and how should these side effects be managed?

Oxcarbazepine (Trileptal) and Sexual Dysfunction

Oxcarbazepine does not cause sexual dysfunction and actually improves pre-existing sexual problems in the majority of patients, making it one of the preferred antiepileptic drugs when sexual function is a concern. 1, 2, 3

Evidence for Sexual Function Improvement

• In a large naturalistic study of 673 male epilepsy patients, 79.4% (181/228) of those with pre-existing sexual dysfunction experienced improvement after switching to oxcarbazepine monotherapy, with an additional 10.1% experiencing complete resolution of sexual problems. 3

• The improvements were particularly pronounced in patients previously treated with enzyme-inducing antiepileptic drugs (like carbamazepine or phenytoin), and importantly, no patients experienced worsening of sexual function. 3

• Oxcarbazepine is consistently classified alongside lamotrigine and levetiracetam as antiepileptic drugs that may actually improve sexual function, in contrast to traditional enzyme-inducing drugs. 1, 2

Mechanism of Benefit

• Traditional enzyme-inducing antiepileptics (carbamazepine, phenytoin) enhance the metabolism of sex steroids, leading to hormonal imbalances that cause sexual dysfunction. 4

• When carbamazepine is replaced with oxcarbazepine, the metabolic and endocrine alterations normalize, and carbamazepine-induced impotency can be cured. 4

• Oxcarbazepine does not induce hepatic enzymes to the same degree as carbamazepine, preserving normal sex hormone levels. 4

Clinical Management Algorithm

If a patient on oxcarbazepine reports sexual dysfunction:

1. First, investigate other causes - the sexual dysfunction is unlikely to be caused by oxcarbazepine itself and may be related to the epilepsy, psychosocial factors, or comorbid medications. 4, 5

2. Review concomitant medications - particularly psychotropic drugs (SSRIs, antipsychotics) which commonly cause sexual dysfunction including decreased libido, erectile dysfunction, and anorgasmia. 5

3. Consider switching FROM other antiepileptics TO oxcarbazepine if the patient is on enzyme-inducing drugs or valproate, as this switch typically improves sexual function. 4, 2, 3

4. If switching is not an option, consider symptomatic treatment with sildenafil for erectile dysfunction, which can be effective independent of the underlying cause. 4

Important Caveats

• Sexual dysfunction in epilepsy is multifactorial, involving the epilepsy itself, hormonal changes, antiepileptic medications, and psychiatric/psychosocial factors. 4, 1, 2

• While oxcarbazepine is generally beneficial for sexual function, rare cases of sexual dysfunction have been reported, though this is uncommon. 2

• The evidence base is stronger for male sexual dysfunction; data in women with epilepsy is more limited but suggests similar mechanisms apply. 5