Having post nasal drip , cant sleep at night, i should i take benadryl (diphenhydramine) or claritin? when should i take it, day or night? thanks.

Allergic Rhinitis: If you feel that the rhinorrhea is due to environmental allergies, then I would suggest trying the Benadryl (diphenhydramine) at night since it can make you drowsy and the Claritin during the day (up to twice daily). If you do not see marked improvement, you may need a medical evaluation and possibly allergy testing.

Benadryl (diphenhydramine) at night: Both Benadryl (diphenhydramine) and Claritin are antihistamines. Benadryl (diphenhydramine) is sedating so if having trouble sleeping then will likely help.

Drip: If you take a Claritin (loratadine) and the drip stops its allergic. Take the pill between 4to 6 pm (before things bloom) for a couple of days. If there's no change and the drip is worse lying down it could be a symptom of silent acid reflux. You then could try an antacid a few hours before bedtime