Antidepressant Medications

Major depression, the kind of depression that will most likely benefit from treatment with medications, is more than just “the blues.” It is a condition that lasts 2 weeks or more, and interferes with a person’s ability to carry on daily tasks and enjoy activities that previously brought pleasure. Depression is associated with abnormal functioning of the brain. An interaction between genetic tendency and life history appears to determine a person’s chance of becoming depressed. Episodes of depression may be triggered by stress, difficult life events, side effects of medications, or medication/substance withdrawal, or even viral infections that can affect the brain.

Depressed people will seem sad, or “down,” or may be unable to enjoy their normal activities. They may have no appetite and lose weight (although some people eat more and gain weight when depressed). They may sleep too much or too little, have difficulty going to sleep, sleep restlessly, or awaken very early in the morning. They may speak of feeling guilty, worthless, or hopeless; they may lack energy or be jumpy and agitated. They may think about killing themselves and may even make a suicide attempt. Some depressed people have delusions (false, fixed ideas) about poverty, sickness, or sinfulness that are related to their depression. Often feelings of depression are worse at a particular time of day, for instance, every morning or every evening.

Not everyone who is depressed has all these symptoms, but everyone who is depressed has at least some of them, co-existing, on most days. Depression can range in intensity from mild to severe. Depression can co-occur with other medical disorders such as cancer, heart disease, stroke, Parkinson’s disease, Alzheimer’s disease, and diabetes. In such cases, the depression is often overlooked and is not treated. If the depression is recognized and treated, a person’s quality of life can be greatly improved.

Antidepressants are used most often for serious depressions, but they can also be helpful for some milder depressions. Antidepressants are not "uppers" or stimulants, but rather take away or reduce the symptoms of depression and help depressed people feel the way they did before they became depressed.

The doctor chooses an antidepressant based on the individual’s symptoms. Some people notice improvement in the first couple of weeks; but usually the medication must be taken regularly for at least 6 weeks and, in some cases, as many as 8 weeks before the full therapeutic effect occurs. If there is little or no change in symptoms after 6 or 8 weeks, the doctor may prescribe a different medication or add a second medication such as lithium, to augment the action of the original antidepressant. Because there is no way of knowing beforehand which medication will be effective, the doctor may have to prescribe first one and then another. To give a medication time to be effective and to prevent a relapse of the depression once the patient is responding to an antidepressant, the medication should be continued for 6 to 12 months, or in some cases longer, carefully following the doctor’s instructions. When a patient and the doctor feel that medication can be discontinued, withdrawal should be discussed as to how best to taper off the medication gradually. Never discontinue medication without talking to the doctor about it. For those who have had several bouts of depression, long-term treatment with medication is the most effective means of preventing more episodes.

Dosage of antidepressants varies, depending on the type of drug and the person’s body chemistry, age, and, sometimes, body weight. Traditionally, antidepressant dosages are started low and raised gradually over time until the desired effect is reached without the appearance of troublesome side effects. Newer antidepressants may be started at or near therapeutic doses.

Early Antidepressants. From the 1960s through the 1980s, tricyclic antidepressants (named for their chemical structure) were the first line of treatment for major depression. Most of these medications affected two chemical neurotransmitters, norepinephrine and serotonin. Though the tricyclics are as effective in treating depression as the newer antidepressants, their side effects are usually more unpleasant; thus, today tricyclics such as imipramine, amitriptyline, nortriptyline, and desipramine are used as a second- or third-line treatment. Other antidepressants introduced during this period were monoamine oxidase inhibitors (MAOIs). MAOIs are effective for some people with major depression who do not respond to other antidepressants. They are also effective for the treatment of panic disorder and bipolar depression. MAOIs approved for the treatment of depression are phenelzine (Nardil), tranylcypromine (Parnate), and isocarboxazid (Marplan). Because substances in certain foods, beverages, and medications can cause dangerous interactions when combined with MAOIs, people on these agents must adhere to dietary restrictions. This has deterred many clinicians and patients from using these effective medications, which are in fact quite safe when used as directed.

The past decade has seen the introduction of many new antidepressants that work as well as the older ones but have fewer side effects. Some of these medications primarily affect one neurotransmitter, serotonin, and are called >selective serotonin reuptake inhibitors (SSRIs). These include fluoxetine (Prozac), sertraline (Zoloft), fluvoxamine (Luvox), paroxetine (Paxil), and citalopram (Celexa).

The late 1990s ushered in new medications that, like the tricyclics, affect both norepinephrine and serotonin but have fewer side effects. These new medications include venlafaxine (Effexor) and nefazadone (Serzone).

Other newer medications chemically unrelated to the other antidepressants are the sedating mirtazepine (Remeron) and the more activating bupropion (Wellbutrin). Wellbutrin has not been associated with weight gain or sexual dysfunction but is not used for people with, or at risk for, a seizure disorder.

Each antidepressant differs in its side effects and in its effectiveness in treating an individual person, but the majority of people with depression can be treated effectively by one of these antidepressants.

continue: Side-Effects of Antidepressant Medications