Professional Opinion: Is it safe to use over-the-counter sleep aids for insomnia?

This week, Randy Dalbow, who is board-certified in internal medicine and practices at Beaufort Memorial Lady's Island Internal Medicine, discusses insomnia -- which, according to some estimates, between 30 and 40 percent of adults experience -- and the use of sleep aids.

Question. Is it safe to use sleep aids on a regular basis? Is melatonin safer than diphenhydramine (found in some over-the-counter sleep aids)? How do we know when we're using them too often? What are the consequences of overuse?

Answer. Insomnia is defined as difficulty with sleep initiation, duration or quality, and it results in daytime sleepiness and dysfunction. Pain, anxiety, acid reflux, sleep apnea, medications and psychoactive substances, such as caffeine, can cause insomnia. It is more common in women, shift workers and the elderly, and it can result in depression, accidents and problems at work.

The first step toward managing insomnia is to maintain a stable sleep and awakening time. It helps to have adequate exposure to light during the day and darkness at night. This enables the brain to know when it's time to sleep and wake up and induces the pineal gland to secrete melatonin when it's nighttime. Limit yourself to a maximum of eight hours in bed. Additionally, avoid use of stimulants after 4 or 5 p.m., don't read or watch TV in bed, and practice relaxation strategies before bedtime. Cognitive behavioral psychotherapy is more effective than drug therapy for insomnia. Six to nine sessions are needed over three weeks.

Antihistamines are often used to treat insomnia, especially diphenhydramine, which is available over the counter in products such as Tylenol PM, Sominex and Unisom. These products have many drug interactions, have a long half-life (the time it takes for half a dosage to be metabolized) and should be avoided for chronic insomnia.

They are a particularly bad choice for elderly patients because of their anticholinergic (meaning inhibiting a specific neurotransmitter) side-effect profile. These side effects include constipation, urine retention, loss of coordination, double vision and dry mouth. Additionally, antihistamines may aggravate glaucoma.

Melatonin is helpful for short-term use, for example if you have jet lag or are a shift worker with sleep difficulties. Many drink alcohol to help with sleep; although it may help you fall asleep, it interferes with sleep architecture and may cause sleep problems in the second half of the night.

Follow reporter Rachel Damgen at twitter.com/IPBG_Rachel.

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This story was originally published April 21, 2014 at 6:11 PM with the headline "Professional Opinion: Is it safe to use over-the-counter sleep aids for insomnia?."