Clomipramine Hydrochloride

Clomipramine, the 3-chloro analog of imipramine, is a dibenzazepine-derivative tricyclic antidepressant (TCA). TCAs are structurally similar to phenothiazines. They contain a tricyclic ring system with an alkyl amine substituent on the central ring. In non-depressed individuals, clomipramine does not affect mood or arousal, but may cause sedation. In depressed individuals, clomipramine exerts a positive effect on mood. TCAs are potent inhibitors of serotonin and norepinephrine reuptake. Tertiary amine TCAs, such as clomipramine, are more potent inhibitors of serotonin reuptake than secondary amine TCAs, such as nortriptyline and desipramine. TCAs also down-regulate cerebral cortical β-adrenergic receptors and sensitize post-synaptic serotonergic receptors with chronic use. The antidepressant effects of TCAs are thought to be due to an overall increase in serotonergic neurotransmission. TCAs also block histamine-H₁ receptors, α₁-adrenergic receptors and muscarinic receptors, which accounts for their sedative, hypotensive and anticholinergic effects (e.g. blurred vision, dry mouth, constipation, urinary retention), respectively. See toxicity section below for a complete listing of side effects. Clomipramine may be used to treat obsessive-compulsive disorder and disorders with an obsessive-compulsive component (e.g. depression, schizophrenia, Tourette’s disorder). Unlabeled indications include panic disorder, chronic pain (e.g. central pain, idiopathic pain disorder, tension headache, diabetic peripheral neuropathy, neuropathic pain), cataplexy and associated narcolepsy, autistic disorder, trichotillomania, onchophagia, stuttering, premature ejaculation, and premenstrual syndrome. Clomipramine is rapidly absorbed from the gastrointestinal tract and demethylated in the liver to its primary active metabolite, desmethylclomipramine.

Clomipramine is a tricyclic antidepressant used in the treatment of obsessive-compulsive disorder and disorders with an obsessive-compulsive component, such as depression, schizophrenia, and Tourette’s disorder.

May be used to treat obsessive-compulsive disorder and disorders with an obsessive-compulsive component (e.g. depression, schizophrenia, Tourette’s disorder). Unlabeled indications include: depression, panic disorder, chronic pain (e.g. central pain, idiopathic pain disorder, tension headache, diabetic peripheral neuropathy, neuropathic pain), cataplexy and associated narcolepsy (limited evidence), autistic disorder (limited evidence), trichotillomania (limited evidence), onchophagia (limited evidence), stuttering (limited evidence), premature ejaculation, and premenstrual syndrome.

• Depression
• Obsessive Compulsive Disorder (OCD)
• Panic Disorder

Clomipramine, a tricyclic antidepressant, is the 3-chloro derivative of Imipramine. It was thought that tricyclic antidepressants work exclusively by inhibiting the re-uptake of the neurotransmitters norepinephrine and serotonin by nerve cells. However, this response occurs immediately, yet mood does not lift for around two weeks. It is now thought that changes occur in receptor sensitivity in the cerebral cortex and hippocampus. The hippocampus is part of the limbic system, a part of the brain involved in emotions. Presynaptic receptors are affected: α₁ and β₁ receptors are sensitized, α₂ receptors are desensitized (leading to increased noradrenaline production). Tricyclics are also known as effective analgesics for different types of pain, especially neuropathic or neuralgic pain.

Clomipramine is a strong, but not completely selective serotonin reuptake inhibitor (SRI), as the active main metabolite desmethyclomipramine acts preferably as an inhibitor of noradrenaline reuptake. α₁-receptor blockage and β-down-regulation have been noted and most likely play a role in the short term effects of clomipramine. A blockade of sodium-channels and NDMA-receptors might, as with other tricyclics, account for its effect in chronic pain, in particular the neuropathic type.

Well absorbed from the GI tract following oral administration. Bioavailability is approximately 50% orally due to extensive first-pass metabolism. Bioavailability is not affected by food. Peak plasma concentrations occurred 2-6 hours following oral administration of a single 50 mg dose. The peak plasma concentration ranged from 56 ng/mL to 154 mg/mL (mean, 92 ng/mL). There are large interindividual variations in plasma concentrations occur, partly due to genetic differences in clomipramine metabolism. On average, steady state plasma concentrations are achieved in 1-2 weeks following multiple dose oral administration. Smoking appears to lower the steady-state plasma concentration of clomipramine, but not its active metabolite desmethylclomipramine.

~ 17 L/kg (range: 9-25 L/kg). Clomipramine is capable of distributing into the cerebrospinal fluid, the brain, and into breast milk.

Clomipramine is approximately 97-98% bound to plasma proteins, principally to albumin and possibly to α₁-acid glycoprotein. Desmethylclomipramine is 97-99% bound to plasma proteins.

Urine (51-60%) and feces via biliary elimination (24-32%)

Following oral administration of a single 150 mg dose of clomipramine, the average elimination half-life of clomipramine was 32 hours (range: 19-37 hours) and of desmethylclomipramine was 69 hours (range: 54-77 hours). Elimination half-life may vary substantially with different doses due to saturable kinetics (i.e. metabolism).

Signs and symptoms vary in severity depending upon factors such as the amount of drug absorbed, the age of the patient, and the time elapsed since drug ingestion. Critical manifestations of overdose include cardiac dysrhythmias, severe hypotension, convulsions, and CNS depression including coma. Changes in the electrocardiogram, particularly in QRS axis or width, are clinically significant indicators of tricyclic toxicity. In U.S. clinical trials, 2 deaths occurred in 12 reported cases of acute overdosage with Anafranil either alone or in combination with other drugs. One death involved a patient suspected of ingesting a dose of 7000 mg. The second death involved a patient suspected of ingesting a dose of 5750 mg. Side effects include: sedation, hypotension, blurred vision, dry mouth, constipation, urinary retention, postural hypotension, tachycardia, hypertension, ECG changes, heart failure, impaired memory and delirium, and precipitation of hypomanic or manic episodes in bipolar depression. Withdrawal symptoms include gastrointestinal disturbances, anxiety, and insomnia.

• Avoid alcohol.
• Avoid grapefruit products.
• Take with food. Food reduces irritation.