Depression Drugs & Weight Loss

Medications for depression are divided into major classes including tricyclic antidepressants, monoamine oxidase inhibitors, selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors. These medications are available with a physician's prescription and are effective for treating the symptoms of depressive disorders. However, many of these drugs may lead to weight loss.

Medications and Actions

The tricyclic antidepressants, or TCAs, include amitriptyline, clomipramine, imipramine, trimipramine, doxepin, amoxapine, nortriptyline, protriptyline and desipramine. These medications work by blocking the reabsorption of the chemicals serotonin and norepinephrine. The monoamine oxidase inhibitors, MAOIs, which include phenelzine and tranylcypromine, work by inhibiting the actions of monoamine oxidase. Selective serotonin reuptake inhibitors, or SSRIs, block the reabsorption of serotonin in the brain. MayoClinic.com explains the increased levels in the brain increases the transmission of nerve impulses and improves mood. The medications that belong in this category include citalopram, escitalopram, fluoxetine, paroxetine and sertraline. The serotonin-norepinephrine reuptake inhibitors, or SNRIs, are bupropion, nefazodone, trazodone, duloxetine and venlafaxine, and they work by blocking the reabsorption of serotonin, norepinephrine and, to some extent, dopamine.

Weight Loss

Weight loss may occur with the use of antidepressants, especially with SSRIs and SNRIs. Fluoxetine may lead to weight loss in about 2 percent of individuals. According to the "Drug Information Handbook," about 14 to 23 percent of individuals on bupropion may notice a decrease in weight. Venlafaxine and duloxetine may cause weight loss in about 2 to 3 percent of patients. Nefazodone and trazodone are also associated with minor weight loss. The TCAs may cause weight loss, but are more commonly associated with increased appetite and weight gain.

GI Side Effects

The weight loss seen with some of the antidepressants may be related to other gastrointestinal side effects. Loss of appetite, dry mouth, abnormal taste in the mouth and stomach pain occur with the TCAs. This might account for the weight loss seen with imipramine, desipramine, nortriptyline and protriptyline. Nausea, vomiting, dry mouth and indigestion are common GI side effects of the SSRIs. Escitalopram and paroxetine may cause decreased appetite, while fluvoxamine may lead to a loss of appetite. Loss of appetite, taste perversion and vomiting may occur in over 10 percent of individuals on an SNRI.

Dangers

You may be concerned about the weight changes that may occur with the antidepressants. A small amount of weight loss is not harmful to the body. However, if you are not exercising more than normal or modifying your caloric intake and you are still losing weight, speak with your physician. Losing too much weight too fast may be dangerous and a sign of something serious. If you lose 10 pounds or 5 percent of your weight without trying in the course of six months to a year, call your physician.

Monitoring

Patients should be monitored regularly for improvements in the symptoms of depression. Patients should also be monitored for the development of side effects, including GI adverse effects and weight loss. Report any side effects to a physician; if any adverse reaction becomes severe, seek emergency care.