Lamotrigine-induced sexual dysfunction and non-adherence: case analysis with literature review(†)

BACKGROUND: Optimal anti-epileptic drug (AED) treatment maximises therapeutic response and minimises adverse effects (AEs). Key to therapeutic AED treatment is adherence. Non-adherence is often related to severity of AEs. Frequently, patients do not spontaneously report, and clinicians do not specifically query, critical AEs that lead to non-adherence, including sexual dysfunction. Sexual dysfunction prevalence in patients with epilepsy ranges from 40 to 70%, often related to AEDs, epilepsy or mood states. This case reports lamotrigine-induced sexual dysfunction leading to periodic non-adherence. AIMS: To report lamotrigine-induced sexual dysfunction leading to periodic lamotrigine non-adherence in the context of multiple comorbidities and concurrent antidepressant and antihypertensive pharmacotherapy. METHOD: Case analysis with PubMed literature review. RESULTS: A 56-year-old male patient with major depression, panic disorder without agoraphobia and post-traumatic stress disorder was well-controlled with escitalopram 20 mg bid, mirtazapine 22.5 mg qhs and alprazolam 1 mg tid prn. Comorbid conditions included complex partial seizures, psychogenic non-epileptic seizures (PNES), hypertension, gastroesophageal reflux disease and hydrocephalus with patent ventriculoperitoneal shunt that were effectively treated with lamotrigine 100 mg tid, enalapril 20 mg qam and lansoprazole 30 mg qam. He acknowledged non-adherence with lamotrigine secondary to sexual dysfunction. With lamotrigine 300 mg total daily dose, he described no libido with impotence/anejaculation/anorgasmia. When off lamotrigine for 48 h, he described becoming libidinous with decreased erectile dysfunction but persistent anejaculation/anorgasmia. When off lamotrigine for 72 h to maximise sexual functioning, he developed auras. Family confirmed patient’s consistent monthly non-adherence for 2–3 days during the past year. CONCLUSIONS: Sexual dysfunction is a key AE leading to AED non-adherence. This case describes dose-dependent lamotrigine-induced sexual dysfunction with episodic non-adherence for 12 months. Patient/clinician education regarding AED-induced sexual dysfunction is warranted as are routine sexual histories to ensure adherence. DECLARATION OF INTEREST: No financial interests. K.R.K. is Editor of BJPsych Open; he took no part in the peer-review of this work. COPYRIGHT AND USAGE: © The Royal College of Psychiatrists 2017. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license.