Mirtazapine

What it is and how it works

Mechanism of Action The mechanism of action of mirtazapine for the treatment of major depressive disorder, is unclear. However, its efficacy could be mediated through its activity as an antagonist at central presynaptic α 2 -adrenergic inhibitory autoreceptors and heteroreceptors and enhancing central noradrenergic and serotonergic activity.

Indications

Mirtazapine tablets are indicated for the treatment of major depressive disorder (MDD) in adults . Mirtazapine tablets are indicated for the treatment of major depressive disorder (MDD) in adults.

Dosage and administration (summary)

• Starting dose: 15 mg once daily; may increase up to maximum recommended dose of 45 mg once daily. • Administer orally once daily, preferably in the evening prior to sleep. • Reduce dose gradually when discontinuing mirtazapine tablets. ( 2.6 , 5.13 ) Recommended Dosage The recommended starting dose of mirtazapine tablets is 15 mg once daily, administered orally, preferably in the evening prior to sleep. If patients do not have an adequate response to the initial 15 mg dose, increase the dose up to a maximum of 45 mg per day. Dose changes should not be made in intervals of less than 1 to 2 weeks to allow sufficient time for evaluation of response to a given dose .

Contraindications

Mirtazapine tablets are contraindicated in patients: • Taking, or within 14 days of stopping, MAOIs (including the MAOIs linezolid and intravenous methylene blue) because of an increased risk of serotonin syndrome . • With a known hypersensitivity to mirtazapine or to any of the excipients in mirtazapine tablets.

Warnings and precautions

• Agranulocytosis: If sore throat, fever, stomatitis or signs of infection occur, along with a low white blood cell count, treatment with mirtazapine should be discontinued and the patient should be closely monitored. • Serotonin Syndrome: Increased risk when co-administered with other serotonergic drugs (e.g., SSRI, SNRI, triptans), but also when taken alone. If it occurs, discontinue mirtazapine and initiate supportive treatment.

Pregnancy

Pregnancy Reproduction studies in pregnant rats and rabbits at doses up to 100 mg/kg and 40 mg/kg, respectively [20 and 17 times the maximum recommended human dose (MRHD) on an mg/m 2 basis, respectively], have revealed no evidence of teratogenic effects.

Storage and supply

Mirtazapine tablets, USP are supplied as: 15 mg Tablets – Yellow, biconvex, capsule shaped film coated tablets with a score line in between “0” and “8” on one side and “A” debossed on the other side. Bottles of 30 NDC 71205-481-30 Bottles of 60 NDC 71205-481-60 Bottles of 90 NDC 71205-481-90 Storage Store at 25°C (77°F).

Source: Mirtazapine (Mirtazapine) — US FDA prescribing information, 2022-08-01, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.