Oxcarbazepine and Dry Cough
Oxcarbazepine is not associated with dry cough as a common side effect. The most commonly reported adverse events with oxcarbazepine are somnolence, dizziness, headache, nausea, and vomiting—cough is not among them 1.
Why This Question Arises: The ACE Inhibitor Connection
When a patient on oxcarbazepine develops dry cough, the critical first step is to review all concurrent medications for ACE inhibitors (ramipril, enalapril, lisinopril), as these are far more likely culprits 2.
ACE Inhibitors as the Primary Pharmaceutical Cause
- ACE inhibitors cause dry cough in 5-35% of patients, making them the most common pharmaceutical cause of chronic dry cough 3, 4
- The cough is typically dry, nonproductive, associated with a tickling or scratching sensation in the throat, and often worse at night 5
- Timing does not exclude ACE inhibitors as the cause—cough can begin within hours of the first dose or be delayed for weeks to months after starting therapy 3, 2
- The mechanism involves accumulation of bradykinin, substance P, and prostaglandins due to inhibition of their degradation 4
Clinical Evaluation Algorithm
Step 1: Medication Review
- Immediately review for ACE inhibitors and discontinue under medical supervision, switching to an angiotensin receptor blocker (ARB) such as candesartan or losartan 2, 6
- Cough typically resolves within 1-4 weeks after stopping the ACE inhibitor, though may take up to 3 months in some patients 3, 2
Step 2: Assess Other Common Causes
- Laryngopharyngeal reflux: Consider in older, overweight patients with diabetes; trial a 4-week course of proton pump inhibitor 2
- Upper airway cough syndrome (postnasal drip): Trial first-generation antihistamine plus decongestant for 2 weeks 2
Step 3: Baseline Investigations
- Obtain chest radiograph and spirometry as mandatory baseline investigations 2
Important Clinical Pitfalls
Do not assume oxcarbazepine is the cause simply because the patient is taking it. In the comprehensive review of oxcarbazepine's adverse event profile, cough was not identified as a recognized side effect 1. While topiramate (another antiepileptic drug) has one case report of associated cough 7, oxcarbazepine lacks even this level of evidence linking it to cough.
Women are at higher risk for ACE inhibitor-induced cough and may develop complications including urinary stress incontinence from severe coughing 5. The cough can be severe enough to interfere with sleep and daily activities 5.
Replacement with another ACE inhibitor will not solve the problem—this is a class effect, and the cough will almost always recur on rechallenge with any ACE inhibitor 4. ARBs like candesartan do not cause cough and are the appropriate alternative 6.