Other Names/Brands

Tofranil

Mechanism of Action

Imipramine HCl works as a tricyclic antidepressant that affects the balance of neurotransmitters in the brain, particularly serotonin and norepinephrine. This drug inhibits the reabsorption of these neurotransmitters across the synaptic cleft, thereby increasing their concentration and activity in the central nervous system. Increased serotonin and norepinephrine levels can lead to more stable moods, reduced depressive symptoms, and reduced anxiety.

Indications

Imipramine HCl is indicated for the treatment of depression, particularly endogenous depression or severe depression accompanied by persistent mood disturbances. It can also be used to treat anxiety disorders and panic disorders and is sometimes prescribed in children for nocturnal enuresis (bedwetting). In some cases, imipramine may be considered for chronic pain disorders due to neuropathy, although its use should be closely monitored by a medical professional.

Contraindications

Imipramine HCl is contraindicated in patients with known hypersensitivity to imipramine or other tricyclic antidepressants. This medication should also not be used in patients who are currently taking, or have taken, monoamine oxidase inhibitors (MAOIs) within the last 14 days, as it may cause hypertensive crisis or other serious reactions.

Imipramine is also contraindicated in patients with severe heart problems such as arrhythmias, congestive heart failure, or a history of myocardial infarction. Its use should also be avoided in patients with narrow-angle glaucoma or urinary retention due to prostatic hypertrophy.

Side Effects

Side effects of imipramine HCl can include anticholinergic symptoms such as dry mouth, constipation, blurred vision, and urinary retention. Additionally, patients may experience drowsiness, dizziness, weight gain, or orthostatic hypotension (low blood pressure upon standing).

In some cases, this medication can also cause cardiovascular effects such as arrhythmias or tachycardia, especially at high doses. Less common but serious side effects include extreme mood swings, seizures, or severe allergic reactions.

Preparations

Imipramine HCl is available in various dosage forms to facilitate use according to patient needs. The most common forms are oral tablets or caplets in various dosage strengths, such as 10 mg, 25 mg, and 50 mg.

Imipramine is also available in extended-release capsules and injectable forms for hospital use under certain conditions. All these preparations should be used according to a doctor's prescription and instructions.

Dosage

The dosage of imipramine HCl varies depending on the patient's age, medical condition, and response to treatment.

• In adults with depression, the starting dose is usually 25–50 mg per day, which can then be gradually increased to a therapeutic dose of 75–150 mg per day, divided into several doses.
• In children with nocturnal enuresis, a lower dose is used, adjusted based on age and weight.

The maximum dose generally does not exceed 200 mg per day for outpatient use. Dose adjustments should be made carefully under the supervision of a physician.

Safety of Drugs

Imipramine HCl is classified as a pregnancy safety category D by the FDA, meaning there is positive evidence of human fetal risk based on research data or clinical experience. However, in certain situations, the benefits of its use in pregnant women may outweigh the risks, such as in cases of severe depression unresponsive to other therapies. Because this drug is excreted in breast milk, its use during breastfeeding is also not recommended.

Drug Interactions

Imipramine HCl can interact with various medications that affect the central nervous system and heart function. Concomitant use with monoamine oxidase inhibitors (MAOIs) is particularly dangerous because it can lead to hypertensive crisis or severe toxic reactions. This medication can also enhance the sedative effects of alcohol, tranquilizers, and antihistamines, increasing the risk of drowsiness and impaired coordination.

Concurrent use with other antiarrhythmic, antipsychotic, or antidepressant medications can increase the risk of heart rhythm disturbances. Interactions with medications that inhibit liver enzymes, such as cimetidine or fluoxetine, can also increase blood levels of imipramine and increase the potential for side effects.

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