Karbinal ER (generic: carbinoxamine) is a prescription medication used to treat runny nose, stuffy nose, watery eyes, and itching caused by hay fever, seasonal and perennial allergies, and other allergic conditions. Karbinal ER belongs to a group of drugs called antihistamines, which work by stopping the action of histamines, a substance produced in the body to react to foreign substances.

This medication comes in an extended-release oral suspension (liquid) form to be taken by mouth, once every 12 hours. It may be taken with or without food.

Common side effects of Karbinal ER include sleepiness, dizziness, loss of coordination, stomach irritation, and thickening of mucus. Do not drive or operate heavy machinery until you know how Karbinal ER affects you.