Which adverse effect is associated with montelukast?

• A. Tachycardia
• B. Headache
• C. Drowsiness
• D. Hypotension

Answer: (B)

Headache is the adverse effect most consistently associated with montelukast. Montelukast blocks leukotriene receptors to reduce inflammation in asthma and allergic rhinitis, and headaches appear as a common, mild-to-moderate side effect in clinical use and labeling. Other options like tachycardia, hypotension, or drowsiness are not typical for this drug; while CNS effects such as sleep disturbances or mood changes can occur, they’re less common than headaches. So headache best fits the known adverse effect profile of montelukast.