Moclobemide – Drug Study & Nursing Implications

GENERAL DESCRIPTION

Moclobemide is a selective and reversible monoamine oxidase inhibitors. It inhibits 80% MAO A and 20-30% MAO B and thus increase the levels of serotonin and norepinephrine and lesser dopamine in the body. Moclobemide is free of hypertensive crisis due to drug-food interaction of tyramine containing food like other MAOIs that is why it is safer than other MAOIs and advantageously use in elderly and cardiovascular patients.

GENERIC NAME: Moclobemide

BRAND NAME: Amira, Clobemix, Depnil

MECHANISM OF ACTION

Moclobemide works by elevating certain neurotransmitter in the brain. At presynaptic serotonergic neuron, this interact with postsynaptic neuron which have postsynaptic receptors which are 5-HT. serotonin is synthesized from amino acid tryptophan by serotonergic neurons. These serotonin is stored in vesicles for regulated release.

At presynaptic noradrenergic neuron, this interact with postsynaptic neuron which have postsynaptic receptors which are β and α1. Norepinephrine is synthesized from amino acid tyrosine by noradrenergic neurons and stored in vesicles awaiting regulated release.

When serotonin and NE release from the neuron they stimulate their receptors and at the same time they transported back to their neurons by a process called reuptake. Serotonin is reuptake by serotonin transporter or SERT and norepinephrine is transported back to their neuron by norepinephrine transporter or NET. Once both chemicals reabsorb they partially repacked in synaptic vesicles in partially broken down into inactive metabolites by an enzyme monoamine oxidase or MAO.

Monoamine oxidase is mitochondrial enzyme that degrades monoamine such as serotonin and epinephrine. MAO enzyme are of two types MAO A and MAO B. They are distributed in brain, gut and liver. MAO A preferably metabolize serotonin but also metabolize norepinephrine and dopamine while MAO B preferably metabolizes dopamine. Therefor inhibition of MAO A may cause antidepressant effects. So mechanism of action of moclobemide is inhibiting the MAO A enzyme preventing breakdown of monoamine neurotransmitter ultimately increasing the availability of these chemicals. It inhibits 80% MAO A and 20-30% MAO B and thus increase the levels of serotonin and norepinephrine and lesser extent dopamine in the body.

PHARMACOKINETICS

Moclobemide is an orally active drug. Its bioavailability is 50-90% and protein binding is 50%. It is metabolized by hepatic CYPs system and acetylation. Moclobemide has 1-2 hours half-life. Moclobemide, act as pro-drugs in that they form active metabolites in vivo which have a greater affinity for MAO-A than the parent compound. MAOIs require daily dosing. It is eliminated by renal excretion.

INDICATIONS

Unipolar and bipolar Depression

Depression with anxiety

Anxiety with panic attack or multiple somatic symptoms

Atypical depression with hypersomnia, lethargy, hyperphagia

Cautionary use with TCAs where TCAs does not affect alone.

Post-traumatic stress disorder

Dysthymia

Social phobia

Fibromyalgia

Migraine (prophylaxis)

Obsessive compulsive disorder

Hysteroid dysphoria

CONTRAINDICATIONS

Thyrotoxicosis

Hepatic failure

Renal failure

Cerebrovascular disease

Pheochromocytoma

Porphyria

Epilepsy

Confusion state

SIDE EFFECTS & ADVERSE EFFECTS

Decrease drug metabolism in the liver

Prevent breakdown of food, alcohol, fruits

Orthostatic hypotension

Weight gain

Sexual dysfunction

Headache

Migraine

Dry mouth

Oedema

Serotonin syndrome

Hypertensive crisis

Psychotic reaction

Withdrawal symptoms may be include agitation, restlessness, panic attack and insomnia

DRUG INTERACTION

Cimetidine may increase the plasma levels of Moclobemide.

Moclobemide increase the alcoholic effects when taken concurrently.

Moclobemide may cause serotonin syndrome when given concurrently with other antidepressants such as SSRIs, TCAs

Moclobemide may cause seizure when given with carbamazepine concurrently

Hypertensive crisis may cause when Moclobemide given with pseudoephedrine, phenylephrine

NURSING INTERVENTION

Enquire the complete health history of the patient including allergy, drug interactions, and family background of depression

Check lab test for CBC, blood glucose, BUN, creatinine, platelets, electrolytes, LFT

Check and identify if any neurological disorder like seizure etc.

Monitor blood pressure and pulse before and during treatment

Administer medicine at night or bed time to avoid drowsiness at day time

Observe mood swing during the treatment

Observe s/s for serotonin syndrome, if any

Observe cardiovascular or neurologic s/s for any disorder, if any

Observe sleep-wake cycle of the patients.

PATIENT EDUCATION

Advise to take medicine at night or bed time to avoid drowsiness at day time and take morning dose early to avoid insomnia.

Advise patient not to discontinue treatment because it may take 2-4 weeks to start antidepressant effects

Inform the patients about the possible side effects of medication specially serotonin syndrome which may be life threatening.

Report immediately if feeling bradycardia, urinary retention, blurred vision, chest pain, and diaphoresis.

Advice to take care and slow change of posture due to dizziness and danger of fall or injuries.

Avoid driving if feeling drowsiness or dizziness.

Do not breast breast feed while taking medicine.

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