Common side effects of doxylamine succinate, found in sleep aids such as Medi-Sleep and Unisom, include drowsiness, dizziness, thickening of mucus in the nose and throat, and dry mouth, nose and throat, states Drugs.com. Many people do not experience any side effects from the medication.
Severe side effects may include convulsions, hallucinations, increased heart rate, tremors and wheezing, states Drugs.com. Additional side effects can include tightness in the chest and decreased alertness. Some people may be allergic to doxylamine and experience hives, rash, difficulty breathing and swelling of the face. Individuals who experience allergic reactions or severe side effects should seek immediate medical treatment. Those who take more than the recommended dosage may experience an overdose with symptoms such as hallucinations, loss of consciousness and seizures, states Drugs.com.
Alcohol, exercise and heat may increase the chances of drowsiness or dizziness. The medication should not be given to children under the age of 12 or women who are nursing, and elderly individuals should use extreme caution when taking doxylamine succinate, states Drugs.com. In addition, the medication may interact with sodium oxybate and cause decreased ability to breathe. It should not be taken by anyone who has taken furazolidone or a MAO inhibitor in the prior two weeks.
Doxylamine succinate is also used as an antihistamine medication, states Drugs.com