All About Antidepressants - Usage, Efficacy, Indications, Adverse effects, and Contraindications

Introduction

Antidepressants target the chemical messengers in the brain to improve mood and behavior. Depression is an illness that affects individuals at any age. It is most commonly found in adults. As depression tends to affect the brain, drugs like antidepressants are prescribed to ease the symptoms. Antidepressant drugs are prescription drugs that are also given to treat other medical conditions.

What Are Antidepressant Medications?

Antidepressants are a class of prescription drugs that treat depression and other conditions like anxiety, insomnia, and chronic pain. Different types of antidepressants are available, and each drug works differently.

Antidepressant drugs are classified into the following groups:

• Selective serotonin reuptake inhibitors (SSRIs).

• Serotonin and norepinephrine reuptake inhibitors (SNRIs).

• Noradrenaline and specific serotonergic antidepressants (NASSAs).

• Tricyclic antidepressants (TCAs).

• Serotonin antagonists and reuptake inhibitors (SARIs).

• Monoamine oxidase inhibitors (MAOIs).

• Serotonin modulators.

• Atypical antidepressants.

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Each drug group has a different mechanism of action and is prescribed accordingly to treat the condition.

How Do Antidepressant Medications Work?

Each antidepressant group has a slightly different mechanism of action. These drugs target the neurotransmitters (chemical messengers that carry signals from one nerve cell to another) to modulate mood and behavior. The main aim of antidepressants is to increase the neurotransmitters.

Antidepressants work to increase serotonin, norepinephrine, or both in the synapse (contact point between two neurons where information is passed from one nerve cell to the other). Serotonin and norepinephrine act to stabilize mood and behavior.

Selective serotonin reuptake inhibitors block the reuptake of serotonin and prolong the serotonergic neurotransmission. Serotonin and norepinephrine reuptake inhibitors act by blocking serotonin. Norepinephrine reuptake in the synapse by increasing postsynaptic receptor stimulation.

Atypical antidepressants have various effects, such as blocking the reuptake of dopamine and norepinephrine at the presynaptic cleft to promote dopamine and norepinephrine release. Serotonin modulators inhibit the reuptake of serotonin at the presynaptic cleft. Tricyclic antidepressants inhibit serotonin and norepinephrine reuptake at the presynaptic neuronal membrane.

Monoamine oxidase enzyme plays a role in catabolizing serotonin, norepinephrine, and dopamine. Monoamine oxidase inhibitors inhibit this enzyme.

What Are the Indications for Antidepressants?

Antidepressant drugs are prescribed to treat the following conditions:

• Depressive disorder.

• Unipolar major depression.

• Premenstrual dysphoric disorder.

• Persistent depressive disorder.

• Major depressive disorder.

• Generalized anxiety disorder.

• Social anxiety disorder.

• Obsessive-compulsive disorder.

• Post-traumatic stress disorder.

• Panic disorder.

• Eating disorders like bulimia nervosa.

• Fibromyalgia.

• Neuropathic pain.

It is given to individuals with depression and alcohol dependence. An antidepressant drug called Bupropion is prescribed to help quit smoking. It also helps in controlling some symptoms of narcolepsy. It is used to relieve pain in individuals with rheumatoid arthritis.

What Are the Adverse Effects of Antidepressants?

The common side effects caused by antidepressants include drowsiness, sexual dysfunction, weight gain, anxiety, dizziness, headache, blurred vision, dry mouth, nausea, rash, asthenia, malaise, and tremor. Syndrome of inappropriate antidiuretic hormone, hyponatremia, and symptoms of hyperprolactinemia may be present in individuals taking antidepressant drugs. The adverse effects are different for each antidepressant group.

This includes:

• SSRIs cause sexual dysfunction, headache, and QTc prolongation (QTc prolongation on electrocardiography indicates an extended interval between the contraction and relaxation of the heart).

• SNRIs cause hypertension, diaphoresis, headache, and bone resorption.

• Atypical antidepressants cause sedation, weight gain, hepatotoxicity, and seizures.

• Serotonin modulators cause acute hepatitis with cholestasis, centrilobular necrosis, diarrhea, nausea, sedation, and priapism.

• Tricyclic antidepressants cause QRS prolongation (indicates delayed ventricular electrical activation), dry mouth, urinary retention, constipation, seizures, and orthostatic hypotension.

• MAO inhibitors cause sexual dysfunction and serotonin syndrome.

What Are the Contraindications of Antidepressants?

Antidepressant drugs are contraindicated in various conditions, and the contraindications vary between and within the antidepressant groups.

This includes:

• Antidepressants are contraindicated in individuals under psychotropic medications.

• It should not be used in individuals with known hypersensitivities.

• Selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors should not be taken with other drugs that belong to selective serotonin reuptake inhibitors, tricyclic antidepressants, monoamine oxidase inhibitors, and other psychotropic drugs. This is contraindicated because combining these drugs causes serotonin syndrome, which leads to severe neuromuscular and autonomic symptoms.

• Tricyclic antidepressants are contraindicated in individuals with cardiovascular diseases like bundle-branch disease.

• Selective serotonin reuptake inhibitors are contraindicated in pregnant women because it increases the risk of spontaneous abortion. It also causes preterm birth and low birth weight.

• Bupropion, an atypical antidepressant drug, is contraindicated in individuals with an active seizure disorder or prior seizure history. It should not be given to individuals with bulimia or anorexia nervosa.

• Nefazodone therapy is contraindicated in individuals with liver injury.

• Esketamine drug is contraindicated in individuals with aneurysmal vascular disease and arteriovenous malformations.

How Effective Are Antidepressants?

Antidepressant drugs are useful in treating individuals with moderate or severe depression. It is not recommended for the treatment of mild depression. Antidepressants are administered in tablet form. The lowest dose is prescribed for one or two weeks to improve the symptoms. The course of treatment may last up to six months until the individual feels better. Once improvement is observed, and the individual is ready to wear off antidepressants, the doctor reduces the dose gradually over several weeks to prevent withdrawal symptoms.

What Are the Complications Associated With Antidepressants?

Antidepressants cause complications like antidepressant-induced mania or hypomania in individuals with or without bipolar disorder. It causes emotional blunting, characterized by a decrease in the intensity of positive and negative emotions. The use of antidepressants is associated with an increased risk of suicidal behavior. It causes cardiovascular complications and increases the risk of death. It also causes discontinuation syndrome or withdrawal syndrome due to the discontinuation of the antidepressant medication. These symptoms include trouble sleeping, nausea, poor balance, sensory changes, anxiety, and flu-like symptoms.

Conclusion

Antidepressants may take time to act, with varying effects from person to person. With doctor’s consultation and the right dosage of antidepressants help to overcome depression gradually. These drugs are prescription medications that can be consumed only under the guidance of a physician. Depression is a major mental illness that can also be managed with cognitive behavioral therapy, interpersonal therapy, problem-solving therapy, and antidepressant medications. However, it is essential to consult the doctor to know the proper management for the prevailing condition.