Product Information
Registration Status: ActiveAPO-MIRTAZAPINE TABLET 30MG is approved to be sold in Singapore with effective from 2011-09-09. It is marketed by PHARMAFORTE SINGAPORE PTE LTD, with the registration number of SIN14012P.
This product contains Mirtazapine 30mg/tab in the form of TABLET, FILM-COATED. It is approved for ORAL use.
This product is manufactured by Apotex Inc. (Etobicoke Site) in CANADA.
It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.
Description
Mirtazapine is an antidepressant introduced by Organon International in 1996 used for the treatment of moderate to severe depression. Mirtazapine has a tetracyclic chemical structure and is classified as a noradrenergic and specific serotonergic antidepressant (NaSSA). It is the only tetracyclic antidepressant that has been approved by the Food and Drug Administration to treat depression.
Indication
For the treatment of major depressive disorder.
Mechanism of Action
Mirtazapine acts as an antagonist at central pre-synaptic alpha(2)-receptors, inhibiting negative feedback to the presynaptic nerve and causing an increase in NE release. Blockade of heteroreceptors, alpha(2)-receptors contained in serotenergic neurons, enhances the release of 5-HT, increasing the interactions between 5-HT and 5-HT1 receptors and contributing to the anxiolytic effects of mirtazapine. Mirtazapine also acts as a weak antagonist at 5-HT1 receptors and as a potent antagonist at 5-HT2 (particularly subtypes 2A and 2C) and 5-HT3 receptors. Blockade of these receptors may explain the lower incidence of adverse effects such as anxiety, insomnia, and nausea. Mirtazapine also exhibits significant antagonism at H1-receptors, resulting in sedation. Mirtazapine has no effects on the reuptake of either NE or 5-HT and has only minimal activity at dopaminergic and muscarinic receptors.
Pharmacokinetics
- Absorption
- Rapid and complete, but, due to first-pass metabolism, absolute bioavailability is 50%.
- Distribution
- Metabolism
- Mirtazapine is extensively metabolized by demethylation and hydroxylation followed by glucuronide conjugation. Cytochrome P450 2D6 and cytochrome P450 1A2 are involved in formation of the 8-hydroxy metabolite of mirtazapine, and cytochrome P450 3A4 is responsible for the formation of the N-desmethyl and N-oxide metabolites. Several metabolites possess pharmacological activity, but plasma levels are very low.
- Elimination
Toxicity
Symptoms of overdose include disorientation, drowsiness, impaired memory, and tachycardia. LD50 is 600-720mg/kg (oral, mice) and 320-490mg/kg (oral, rat) [PMID: 10333982]
Active Ingredient/Synonyms
1,2,3,4,10,14b-Hexahydro-2-methylpyrazino(2,1-a)pyrido(2,3-c)benzazepine | 6-Azamianserin | Mepirzapine | Mirtazapin | Mirtazapina | Mirtazapine | Mirtazapinum | Mirtazapine |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.