Which of the following is a common side effect of methylphenidate when used for ADHD?

• A. Irritability
• B. Headache
• C. Vomiting
• D. Hypertension

Answer: (B)

Methylphenidate’s stimulant action increases brain adrenalin and dopamine activity, which often shows up as common adverse effects. Headache is one of the most frequently reported side effects with this medication, especially early on, because the heightened CNS activity can affect cerebral blood flow and pain perception. This makes headaches a predictable, dose-related issue that many patients experience and that often improves with time or with gradual dose adjustments. While irritability and, less commonly, vomiting or high blood pressure can occur, headaches occur more consistently across patients, which is why this option is the best answer.