There are several over-the-counter medications that can help stop a runny nose. Antihistamines such as chlorpheniramine and diphenhydramine can relieve allergy-induced runny nose by reducing the allergic response and drying up mucus. Decongestants such as Sudafed (pseudoephedrine) can relieve congestion and reduce the amount of mucus released. However, decongestants can interfere with sleep and cause insomnia and agitation, so they should be taken well before bedtime. Topical anticholinergics, such as ipratropium bromide nasal spray, may also help reduce a runny nose, but this medicine requires a prescription from a doctor. Saline treatments or flushing the sinuses might be helpful but won’t completely stop a runny nose. It is important to identify the underlying cause of the runny nose and treat the illness or condition accordingly. If nasal symptoms last longer than 10 days and over-the-counter medications don’t provide relief, it is recommended to consult a doctor.