Oxcarbazepine and Dry Cough: No Established Association
Oxcarbazepine is not associated with dry cough as a recognized adverse effect, and there is no evidence linking this anticonvulsant to cough in patients with or without allergies or asthma.
Evidence Review
Lack of Cough as a Documented Side Effect
The most comprehensive review of oxcarbazepine's adverse effect profile identifies asthenia, headache, dizziness, somnolence, nausea, diplopia, and skin rash as the most frequently associated symptoms, with no mention of cough 1
Hyponatremia requiring close electrolyte monitoring is the most serious concern with oxcarbazepine, not respiratory symptoms 1
Drug-Induced Cough: The Real Culprits
When evaluating chronic dry cough in patients on multiple medications, the diagnostic approach should focus on:
ACE inhibitors are the primary pharmaceutical cause of chronic dry cough, occurring in 5-35% of patients, often beginning weeks to months after initiation 2
The mechanism involves accumulation of bradykinin, substance P, and prostaglandins due to inhibition of their degradation 2
If a patient on oxcarbazepine develops dry cough, review all concurrent medications for ACE inhibitors (ramipril, enalapril, lisinopril) as these are far more likely culprits 2, 3
Other Anticonvulsants and Cough
Carbamazepine (structurally related to oxcarbazepine) has rare case reports of pulmonary toxicity with cough, but this presents with fever, dyspnea, and bilateral infiltrates—not isolated dry cough 4
Topiramate has one case report of drug-induced cough, but this is exceptionally rare 5
Clinical Algorithm for Dry Cough Evaluation
When a patient on oxcarbazepine presents with dry cough:
Immediately review for ACE inhibitors - discontinue under medical supervision and switch to an angiotensin receptor blocker (ARB) such as candesartan or losartan 2, 3, 6
Assess for laryngopharyngeal reflux - particularly in older, overweight patients with diabetes; consider 4-week trial of proton pump inhibitor 2, 3
Evaluate for upper airway cough syndrome (postnasal drip) - trial of first-generation antihistamine plus decongestant for 2 weeks 7
Obtain chest radiograph and spirometry as mandatory baseline investigations 7
Do not attribute cough to oxcarbazepine unless all other causes have been systematically excluded and temporal relationship is compelling
Important Caveats
Cough from ACE inhibitors can begin within hours or be delayed for months after starting therapy, so timing alone does not exclude this diagnosis 2
Resolution of ACE inhibitor-induced cough typically occurs within 1-4 weeks after discontinuation, though may take up to 3 months 2
ARBs like candesartan have a cough incidence similar to placebo (26.9% vs 35.5%) compared to enalapril (68.2%) in patients with previous ACE inhibitor-induced cough 6