Nefazodone

Definition

Nefazodone is a prescription antidepressant. Nefazodone is available in the United States under the trade name of Serzone.

Purpose

Nefazodone is used to treat depression. It may be used to treat major depressive disorder , dysthymic disorder , and the depressed phase of bipolar disorder . As with all antidepressants, it may take several weeks before full beneficial effects are seen.

Description

Nefazodone was approved by the FDA in 1994. It is believed to increase the activities of some chemicals in the brain . By altering the activities of specific brain chemicals, nefazodone may reduce the chemical imbalances responsible for causing depression.

The drug is available as tablets in several different strengths, including 50-, 100-, 150-, 200-, and 250-mg tablets.

Nefazodone is broken down by the liver.

Recommended dosage

For most people, the recommended initial dose of nefazodone is 100 mg taken by mouth twice daily. The dose may be increased in 100 or 200 mg increments once a week. Most commonly, final dosages range between 300-600 mg taken by mouth each day.

It is recommended that the initial dose of nefazodone be lowered to 50 mg twice daily for elderly or debilitated individuals, because these individuals may be more sensitive to some of the drug's side effects.

Precautions

People who have a history of epilepsy or other seizure disorders, heart attack, stroke , high blood pressure, or mania may require close physician supervision while taking nefazodone. Nefazodone may increase the tendency to have seizures , and should be used carefully by people with epilepsy or other seizure disorders. Nefazodone may lower blood pressure. This effect may be most noticeable when rising suddenly from a lying or sitting position. People with a history of heart attack or stroke, those taking medications for high blood pressure, or people who are dehydrated may be most sensitive to this effect and may feel dizzy or faint when standing up suddenly. Nefazodone may alter moods or cause mania, so patients with a history of mania should use nefazodone with caution.

In rare situations, men taking nefazodone may experience long, painful erections. If this occurs, a health care provider should be notified immediately.

Because there is an increased likelihood of suicide in depressed individuals, close supervision of those at high risk for suicide attempts is recommended. Nefazodone is not recommended for pregnant or breast-feeding women.

Side effects

The most common side effects that cause people to stop taking nefazodone are dizziness, difficulty sleeping, weakness, or agitation. Other common adverse effects are sleepiness, dry mouth, nausea, constipation, blurred vision, and confusion.

Other, less common adverse effects associated with nefazodone are headache, flu-like symptoms, low blood pressure, itching, rash, upset stomach, fluid retention, muscle aches, thirst, memory impairment, nerve pain, nightmares, difficulty walking, ringing in the ears, urinary difficulties, breast pain, or vaginal irritation.

It has recently been discovered that in rare situations, nefazodone causes liver failure. If nausea, stomach pains, yellowing of the skin or eyes, itching, or darkening of urine occurs while taking nefazodone, a health care professional should be consulted immediately.

Interactions

Use of nefazodone with antidepressants referred to as monoamine oxidase inhibitors (MAOIs) is strongly discouraged due to the potential for high fever, muscle stiffness, sudden muscle spasms, rapid changes in heart rate and blood pressure, and the possibility of death. In fact, there should be a lapse of at least 14 days between taking a monoamine oxidase inhibitor and nefazodone or at least seven days should pass if switching from nefazodone to a monoamine oxidase inhibitor. Some examples of MAOIs include phenelzine (Nardil) and tranylcypromine (Parnate).

Some other drugs such as trazodone (Desyrel) and sibutramine may also interact with nefazodone and cause a syndrome characterized by irritability, muscle stiffness, shivering, muscle spasms, and altered consciousness. If nefazodone is used with buspirone (BuSpar), the dosage of buspirone should be lowered to prevent adverse effects. Additionally, when nefazodone is used in combination with digoxin (Lanoxin), frequent monitoring of blood levels of digoxin is recommended to prevent toxicity.

Nefazodone should not be used with the drugs triazolam (Halcion) and alprazolam (Xanax) because the side effects of these drugs are likely to increase. Use of nefazodone should also be avoided with carbamazepine (Tegretol), because nefazodone is likely to lose its effectiveness.

It is best to avoid using nefazodone with pimozide (Orap) due to an increased tendency for severe and potentially life-threatening irregular heartbeats.

When used with gemfibrozil or other drugs that lower cholesterol levels, the risk of muscle pain and weakness may be increased.

Because nefazodone may cause drowsiness, it should be used carefully with other medications that also make people prone to sleepiness such as antidepressants, antipsychotics, antihistamines, and alcohol.

Resources

BOOKS

Bristol-Meyers Squibb Staff. Serzone Package Insert. Princeton, NJ: Bristol-Meyers Squibb Company, 2001.

Facts and Comparisons Staff. Drug Facts and Comparisons. 6th Edition. St. Louis, MO: A Wolter Kluwer Company, 2002.

Mosby Staff. Mosby's Medical Drug Reference. St. Louis, MO: Mosby, Inc, 1999.

Kelly Karpa, RPh, Ph.D.