Millions of insomniacs are prescribed sleeping pills to help with their ailment. Although they can be safe and effective in the short term, long-term use of such drugs poses some health risks.

Most of these medicines — including benzodiazepines and barbiturates — belong to a class of drugs called sedative-hypnotics, which can be used to treat both anxiety and insomnia.

Unfortunately, these drugs can impair memory and attention, and people who take them also run the risk of forming a chemical dependence.

Examples of benzodiazepines include Ativan, Valium, Xanax, and Librium. Barbiturates are an older type of sedativehypnotic medicines that have been replaced by benzodiazepines, which have become the more popular sleep medicines.

This may be partly due to the fact that barbiturates carry serious side effect risks, including death from overdose.

Newer medicines that affect the same brain receptors as benzodiazepines include Lunesta, Ambien, and Sonata. These drugs are less habit-forming than benzodiazepines, but can still cause physical dependence from chronic use.

There are many potential side effects from these medicines. They can interfere with normal breathing, posing a particular risk for patients with asthma or emphysema. Other possible side effects include change in appetite, diarrhea or constipation, daytime drowsiness, dry mouth, headache, mental sluggishness, abdominal pain, and weakness.

In rare situations, people develop parasomnias, which are behaviors or movement during sleep that they cannot control. These behaviors can be complex and include sleepwalking, sleep eating, making phone calls or even driving.

A new sleep medication, Rozerem, has biological effects similar to melatonin, the natural human hormone that helps regulate sleep and wake cycles. Belsomra is yet another new sleeping aid that is less habit-forming than the others.

A common problem is mixing alcohol with sleeping pills, which increases the effects of both drugs. This potentially lethal combination can cause people to lose consciousness and stop breathing.

Grapefruit or grapefruit juice can increase the amount of a sleeping medication that is absorbed into the bloodstream and how long it stays in the body. That can cause too much or unwanted sedation.

Doctors may prescribe any of these medicines for short-term insomnia, but you should try not to use them for longer periods in order to avoid dependence and possible side effects.

If you have been taking these kinds of pills regularly and you find you can’t sleep without them, you may be physically or emotionally dependent on them. You and your doctor should discuss ways to wean yourself off the medicines and substitute alternate techniques to help you sleep through the night.