Omeprazole-induced intractable cough.

Objective: To report a case of chronic, persistent cough induced by omeprazole therapy.

Case Summary: A 42-year-old white woman presented with chronic, persistent cough after omeprazole initiation for treatment of postoperative heartburn. The cough was permanent, dry, and exhausting and worsened at night. Omeprazole therapy was continued for 4 months because the persistent cough was thought to be related to gastroesophageal reflux disease (GERD). However, no cause of persistent, chronic cough was identified. After omeprazole discontinuation, the cough resolved.

Discussion: The most common causes of chronic cough in nonsmokers of all ages are postnasal drip syndrome, asthma, and GERD. However, persistent cough without bronchospasm or other pulmonary involvement may occur as a drug adverse effect. According to the US omeprazole package insert, cough is observed as an adverse reaction in 1.1% of patients, although this has not been mentioned in international drug information sources or medical literature. A MEDLINE search (1966-June 2003) using the terms cough, drug related, adverse effects, and omeprazole failed to find any data. In our patient, there was a temporal relationship between cough and medication use, suggesting a causal relationship. An objective causality assessment revealed that the adverse drug reaction was probable. The mechanism is unclear.

Conclusions: Chronic, persistent cough may occur as an adverse effect of omeprazole therapy. Clinicians must be aware of this adverse effect to avoid useless and costly tests.