A variety of over-the-counter sleep aids are available, usually with the antihistamine diphenhydramine as the active ingredient. Beside treating allergies and the common cold, the drug can be used as a treatment for rashes, itching, insect bites, motion sickness and mild forms of Parkinson's disease. Recommended doses for occasional insomnia treatment range from 25mg to 50mg. Signs of sleep aid overdose may become apparent when too medication is taken. Symptoms of overdose are sometimes pronounced in those who are hypersensitive to the drug or when used in combination with alcohol, tricyclic depression medication or other antihistamines.
Hallucinations
One sign of overdose with a sleep aid is hallucinations. Because antihistamines work in the brain to cause drowsiness, they may also cause irregular thought patterns that manifest as hallucinations. RxMed recommends diphenhydramine not be used at all with elderly patients who have exhibited confused behavior at nighttime. Because the drug may also have the opposite effect of producing excitability with the geriatric population, the drug isn't recommended at all for this age group.
Loss of Consciousness
Another sign of sleep aid overdose is loss of consciousness. This differs from natural sleep in that the person can't be awakened normally. Drugs.com states that the condition is serious and can cause the patient to become comatose. If overdose with a sleep aid is suspected, emergency medical care should be sought.
Tremors
A sign of overdose with sleep aid is tremors. The unnatural body movements may appear as muscle twitching. Lack of voluntary muscle control is also a problem, according to the New York Time Health Guide. Shaking, unsteadiness and muscle weakness may also be displayed as signs of overdose.
Seizures
Sleep aid overdose may display as seizures. Drugs.com states that seizures and convulsions may worsen if the sleep aid is combined with drugs which increase the effects. Beside other antihistamines and alcohol, drugs that should likewise be avoided are monoamine oxidase inhibitors such as isocarboxazid, phenelzine or tranylcypromine.
