Mitaprex 7.5

Indications

Mitaprex Tablets are prescribed for managing major depressive disorder (MDD).
Consult a registered healthcare professional before use.

Pharmacology

Pharmacodynamics: The precise mechanism by which Mirtazapine exerts its antidepressant effects remains unclear. Preclinical studies suggest that Mirtazapine enhances noradrenergic and serotonergic activity in the central nervous system. It acts as an antagonist at central presynaptic α2-adrenergic autoreceptors and heteroreceptors, which may lead to increased levels of norepinephrine and serotonin. Additionally, Mirtazapine strongly antagonizes 5-HT2 and 5-HT3 receptors while displaying minimal affinity for 5-HT1A and 5-HT1B receptors. Its potent antagonism of histamine (H1) receptors likely contributes to its sedative properties. Mirtazapine also has moderate peripheral α1-adrenergic antagonism, which can lead to occasional orthostatic hypotension, and it exhibits moderate antagonistic activity at muscarinic receptors, correlating with a lower occurrence of anticholinergic side effects.

Pharmacokinetics: Upon oral administration, Mirtazapine is quickly absorbed, achieving peak plasma concentrations within approximately 2 hours. About 85% of Mirtazapine binds to plasma proteins. The elimination half-life ranges from 20 to 40 hours (averaging 26 hours in males and 37 hours in females), supporting once-daily dosing. Mirtazapine follows linear pharmacokinetics within the recommended dosage range and undergoes extensive metabolism, primarily via demethylation and oxidation followed by conjugation, with excretion occurring through urine and feces over four days.

Dosage & Administration

Adult Dosage: The recommended initial dosage for Mirtazapine tablets is 15 mg once daily, ideally taken in the evening or before sleep. The effective dosage typically ranges from 15 mg to 45 mg per day; patients not responding to the initial dose may benefit from increasing to 30 mg or up to the maximum of 45 mg daily. Due to the drug’s half-life, dosage adjustments should be spaced at least 1 to 2 weeks apart to allow adequate time for therapeutic effects.

Use in Children: Mirtazapine is not recommended for pediatric use.

Missed Dose: If a dose is missed, take it as soon as remembered unless it’s nearly time for the next dose. In that case, skip the missed dose and continue with the regular schedule. Avoid taking double doses.

Consult a registered healthcare professional before use.

Interaction

Mitaprex can have significant interactions with Monoamine Oxidase Inhibitors (MAOIs) and other serotonergic medications, including tryptophan, triptans, linezolid, serotonin reuptake inhibitors, venlafaxine, lithium, tramadol, and St. John’s wort. It may also affect the metabolism or efficacy of Carbamazepine, Phenytoin, or Cimetidine. Patients should refrain from consuming alcohol or taking Diazepam while on Mitaprex.

Contraindications

• Hypersensitivity: Mirtazapine is contraindicated in individuals with a known hypersensitivity to Mirtazapine or any of its components.
• Monoamine Oxidase Inhibitors: The use of Mirtazapine with MAO inhibitors is prohibited. It should not be used within 14 days of initiating or stopping MAOI therapy.

Side Effects

Common side effects of Mitaprex may include dizziness, drowsiness, dry mouth, increased appetite, and weight gain.

Pregnancy & Lactation

Pregnancy Category C. Patients should inform their healthcare provider if they become pregnant or plan to during Mirtazapine treatment. Additionally, nursing mothers should discuss breastfeeding with their physician.

Precautions & Warnings

Patients, along with their families and caregivers, should monitor for signs of anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia, hypomania, mania, or any unusual behavioral changes, particularly at the beginning of treatment or after dose adjustments. Mitaprex may pose a risk of agranulocytosis and may impair judgment and motor skills due to its sedative effects. Clinically significant elevations in ALT (SGPT) may occur.

Therapeutic Class

Atypical antidepressant drugs.

Storage Conditions

Store in a cool, dry place, away from light and moisture. Keep out of reach of children, and maintain temperatures below 30ºC.