3. Corticosteroids

Why they're prescribed: Corticosteroids are used to treat inflammation of the blood vessels and muscles as well as rheumatoid arthritis, lupus, Sjögren's syndrome, gout and allergic reactions.

Examples: cortisone, methylprednisolone (Medrol), prednisone (sold under many brand names, such as Deltasone and Sterapred) and triamcinolone.

How they can cause insomnia: People often ask why a drug that reduces inflammation would keep them awake. The answer lies in the adrenal glands, which are responsible for regulating the body's fight-or-flight response. Too much stress can keep the body awake and the mind stimulated by exhausting the adrenal glands; corticosteroids can do the same thing, wreaking havoc on all the systems that allow you to relax and sleep, causing insomnia and unpleasant dreams.

Alternatives: Ask your doctor or pharmacist whether you can take your medication in a single dose early in the day.

4. SSRI antidepressants

Why they're prescribed: SSRIs (selective serotonin-reuptake inhibitors) are used to treat symptoms of moderate to severe depression. SSRIs block the reabsorption (reuptake) of the neurotransmitter serotonin in the brain, which may help brain cells send and receive chemical messages, easing depression. They're called selective because they seem to primarily affect serotonin, not other neurotransmitters.

Examples: citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem), fluvoxamine (Luvox), paroxetine (Paxil, Pexeva) and sertraline (Zoloft).

How they can cause insomnia: Just as it isn't known exactly how SSRIs work, it isn't known exactly how these drugs interfere with sleep. Studies have shown, however, that SSRIs cause agitation, insomnia, mild tremor and impulsivity in 10 percent to 20 percent of the people who take them.

Although about half of people who take SSRIs say that the drugs make them feel better, many continue to struggle with symptoms that can make life miserable, especially insomnia. We know this from researchers at the University of Texas Southwestern Medical Center in Dallas, who combed through data from the STAR*D trial, the largest and longest study ever done on depression treatment, and published their findings in 2011. Almost all of the subjects in the Star*D trial, which was funded by the National Institute of Mental Health, said they continued to have problems with insomnia, with 81 percent reporting being unable to sleep in the middle of the night.

Alternatives: If you are experiencing anxiety or insomnia while on an SSRI (or any other antidepressant, for that matter), it's important to tell your prescribing doctor right away. Sleeplessness — in itself a marker of depression — can make you even more depressed.

Because antidepressants vary in their side effects, a change in dosage or switching to another medication may help you feel better without causing insomnia or other sleep disturbances. A selective serotonin/norepinephrine reuptake inhibitor (SSRI/SNRI), a newer-generation antidepressant, offers some advantages in improving relaxation and sleep. Of the three drugs in this category (clomipramine, duloxetine and venlafaxine), I find venlafaxine to have the least adverse side effects in older patients and to be easier to dose to a therapeutic level.

Many people find that cognitive behavior therapy works just as well as medication. (Cognitive therapy aims to help people overcome their difficulties by changing their thinking, behavior and emotional responses.) Others report success with such approaches as acupuncture, exercise, changes in diet, meditation, relaxation therapy and the like.

Next page: ACE inhibitors. »