Depression

A mood disorder characterized by sadness and pessimism, multifactorial causes

Electroconvulsive therapy (ECT) is increasingly used for refractory and severe cases, and prophylactically once the patient returns to baseline

Treatment

Based on the presumption that its manifestations are due to a brain deficiency of dopamine, norepinephrine, and serotonin or altered receptor activities

Three classes of drugs

Tricyclic antidepressants

Desipramine (Norpramin and Pertofrane) and nortriptyline (Pamelor and Aventyl) are often used

• Due to less sedation effect and with fewer side effects

Other agents more sedating: amitriptyline (Elavil), Imipramine (Tofranil and Janamine), protriptyline (Vivactil), amoxapine (Asendin), doxepin (Sinequan and Adapin), and trimipramine (Surmontil)

• Clomipramine (Anafranil) is used for obsessive-compulsive disorders

Used for depression and chronic pain syndromes

Significant anticholinergic (antimuscarinic) actions

• Dry mouth, blurred vision, prolonged GI emptying, urinary retention

Quinidine-like effects

• Tachycardia, T-wave flattening/inversion, prolongation of PR, QRS, QT intervals

Amitriptyline has the most marked anticholinergic effects; Doxepin has the fewest cardiac effects.

The most important interaction is an exaggerated response to both indirect-acting vasopressors and sympathetic stimulation

Chronic therapy with tricyclic antidepressants is reported to deplete cardiac catecholamines, theoretically potentiating the cardiac depressant effect of anesthetics

If hypotension occurs, small doses of a direct-acting vasopressor (neosynephrine) should be used instead of an indirect-acting agent (ephedrine)

Monoamine oxidase (MAO) inhibitors

Used for patients with depression along with panic attacks and anxiety

• They block the oxidative deamination of naturally occurring amines

Side effects

• Orthostatic hypotension, agitation, tremor, seizures, muscle spasms, urinary retention, paresthesia, and jaundice
• May see hypertensive crisis due to ingestion of tyramine-containing foods (cheeses and red wine)

Nonselective MAO inhibitors are the agents used for the treatment

MAO A is selective for serotonin, dopamine, and norepinephrine

MAO B is selective for tyramine and phenylethylamine - not an effective treatment for depression

Avoid the use of opioids, especially Meperidine, which can cause hyperthermia, seizures, and coma (rare)

Atypical antidepressants

Fluoxetine (Prozac), sertraline (Zoloft), and paroxetine (Paxil) are first-line drugs. Others are bupropion (Welbutrin), venlafaxine (Effexor), trazodone (Desyrel), nefazodone (Serzone), fluvoxamine (Luvox), maprotiline (Ludiomil), mirtazapine (Remeron)

Primarily, selective serotonin reuptake inhibitors (SSRIs) have little or no anticholinergic effect and do not affect cardiac conduction

Side effects

• Headache, agitation, and insomnia

Little is known about anesthetic interactions

Anesthetic considerations

The mechanisms of action of these drugs result in potentially serious anesthetic interactions

Pancuronium, Ketamine, Meperidine, and epinephrine containing local anesthetic solutions should be avoided as they can cause exaggerated responses to vasopressors and sympathetic stimulation

St. John's wort is increasingly used for depression (OTC).

Review OTC medications. Induces hepatic enzymes, so blood levels of other drugs may decrease

Anti-depressants are generally continued perioperatively

Chronic therapy with tricyclic antidepressants is reported to deplete cardiac catecholamines, theoretically potentiating the cardiac depressant effect of anesthetics

Up to 50% of patients with major depression hypersecrete cortisol and have abnormal circadian secretion