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.