Benadryl Cough Formula Syrup can cause drowsiness and sleepiness because it contains an antihistamine with a sedating effect. Drowsiness is a known side effect of this medicine, but it should not significantly interfere with daily activities. If the sleepiness is affecting your routine or ability to manage daily responsibilities, you should consult your doctor. The doctor may adjust the dose or recommend an alternative medicine with less sedative effect. Do not stop or change the medicine without medical advice.

A dry cough lasting 4-6 months may be due to allergies, asthma, acid reflux, or post-nasal drip. You need a detailed evaluation, chest X-ray, and possibly an allergy or lung function test. Consult a pulmonologist for long-term management.

A dry cough only in the morning is often due to post-nasal drip, acid reflux, or dust/allergens in your sleeping environment. If it continues for more than 2-3 weeks, get checked to rule out asthma or sinus issues.