Antidepressants

Antidepressants

INTRODUCTION

Antidepressants are drugs, which enhance alertness and may result in an increased output of behaviour. They are used for the relief of symptoms of moderate and severe depressive disorder.

Depression is characterized by feelings of intense sadness or worry, agitation, self-depression, physical changes, such as insomnia, anorexia, loss of enthusiasm, and mental slowing. Major depression is one of the most common psychotic disorders. At any given moment, about 5%–6% of the population is depressed and estimated 10% of the people may become depressed during their lives. Depression is a heterogeneous disorder that has been characterized and classified into a variety of types.

1. Reactive or secondary depressor (occurs in response to illness and it is most common).

2. Endogenous depression (a genetically determined biochemical disorder).

3. Depression associated with bipolar effect (manic depression).

Endogenous depression occurs due to low concentration of various biogenic amines and other modulators of nervous transmission at neuronal level. Antidepressants are typically taken for at least 4–6 months.

Uses

Therapeutic uses of antidepressants are as follows:

• Moderate to severe depressive illness.

• Severe anxiety and panic attacks.

• Obsessive compulsive disorders.

• Chronic pain.

• Eating disorder.

• Post-traumatic stress disorder.

Antidepressants increase the availability of catecholamines at the appropriate receptor sites of the brain. Most of the antidepressants exerts important actions on the metabolism of monoamine neurotransmitters and their receptors particularly norepinephrine (NE) and serotonin. Their therapeutic activeness and actions together with strong evidence from genetic predisposition have lead to the speculation that the biological basis of major mood disorders may include abnormal function of monoamine neurotransmission disorders, including panicagoraphobia, social and other phobias generalized anxiety and obsessive compulsive disorders that appear to be responsive with selective serotonin reuptake inhibitor. Mania and their association with bipolar disorders are less common than major depression. Mania and its milder form is treated with anti-psychotics, anticonvulsants, or lithium salts, sometimes supplemented with a potent sedative in short term and lithium salts or any anticonvulsants with mood stabilizing property. Imipramine, Amitryptaline, and their N-de-methyl derivatives are widely used for major depression. The ability of monoamine oxidase (MAO) inhibitors were noted in 1950, and they are also used in therapy for major depressions, but has limitations due to the toxicities. Presently, selective serotonin reuptake inhibitors, such as Fluoxetine, Fluoxamine, Paraxetine, Sertaline, and Venlafaxine are used.