Below are the general guidelines for dosing Mirtazapine. Note that these dosages may be adjusted on a case-by-case basis for individual patients. Always follow your prescribing physician’s instructions for taking Mirtazapine.
The following information comes from DailyMed, an FDA label information provider.
What if I miss a dose of Mirtazapine?
According to Mayo Clinic, if you miss a dose of Mirtazapine, take it immediately unless you are closer in time to your next dose. Never double doses.
What if I overdose on Mirtazapine?
Human Experience
In premarketing clinical studies, there were reports of mirtazapine tablets overdose alone or in combination with other pharmacological agents. Signs and symptoms reported in association with overdose included disorientation, drowsiness, impaired memory, and tachycardia.
Based on postmarketing reports, serious outcomes (including fatalities) may occur at dosages higher than the recommended doses, especially with mixed overdoses. In these cases, QT prolongation and Torsades de Pointes have also been reported [SEE WARNINGS AND PRECAUTIONS (5.5),ADVERSE REACTIONS (6.2), and DRUG INTERACTIONS (7)].
Overdose Management
No specific antidotes for mirtazapine are known.
Contact Poison Control (1-800-222-1222) for the latest recommendations.
Dosage and Administration
2.1 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 [SEE CLINICAL PHARMACOLOGY (12.3)].
2.3 Screen for Bipolar Disorder Prior to Starting Mirtazapine Tablets
Prior to initiating treatment with mirtazapine tablets or another antidepressant, screen patients for a personal or family history of bipolar disorder, mania, or hypomania [SEE WARNINGS AND PRECAUTIONS (5.8)].
2.4 Switching Patients to or from a Monoamine Oxidase Inhibitor Antidepressant
At least 14 days must elapse between discontinuation of a monoamine oxidase inhibitor (MAOI) antidepressant and initiation of mirtazapine tablets. In addition, at least 14 days must elapse after stopping mirtazapine tablets before starting an MAOI antidepressant [SEE CONTRAINDICATIONS (4) and WARNINGS AND PRECAUTIONS (5.3)].
2.5 Dosage Modifications Due to Drug Interactions
Strong CYP3A Inducers
An increase in dosage of mirtazapine tablets may be needed with concomitant strong CYP3A inducer (e.g., carbamazepine, phenytoin, rifampin) use. Conversely, a decrease in dosage of mirtazapine tablets may be needed if the CYP3A inducer is discontinued [SEE DRUG INTERACTIONS (7)].
Strong CYP3A Inhibitors
A decrease in dosage of mirtazapine tablets may be needed with concomitant use of strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin). Conversely, an increase in dosage of mirtazapine tablets may be needed if the CYP3A4 inhibitor is discontinued [SEE DRUG INTERACTIONS (7)].
Cimetidine
A decrease in dosage of mirtazapine tablets may be needed with concomitant use of cimetidine. Conversely, an increase in dosage of mirtazapine tablets may be needed if cimetidine is discontinued [SEE DRUG INTERACTIONS (7)].
2.6 Discontinuation of Mirtazapine Tablets Treatment
Adverse reactions may occur upon discontinuation or dose reduction of mirtazapine tablets [SEE WARNINGS AND PRECAUTIONS (5.13)]. Gradually reduce the dosage of mirtazapine tablets rather than stopping abruptly whenever possible.
How is Mirtazapine supplied?
Mirtazapine tablets, USP are supplied as:
| Tablet Strength | Tablet Color/Shape | Tablet Markings | Package Configuration | NDC Code |
| 7.5 mg | Yellow, circular, biconvex tablet | film coated tablets with “C” debossed on one side and plain on the other side | Bottle / 30 count | NDC 57664-510-83 |
| 15 mg | Yellow, oval, biconvex tablet | film coated tablets with “499” debossed on one side and scored on the other side | Bottle / 30 count | NDC 57664-499-83 |
| Bottle / 1000 count | NDC 57664-499-18 | |||
| 30 mg | Reddish-brown, oval, biconvex tablet | film coated tablets with “500” debossed on one side and scored on the other side | Bottle / 30 count | NDC 57664-500-83 |
| Bottle / 1000 count | NDC 57664-500-18 | |||
| 45 mg | White to off-white, oval, biconvex tablet | film coated tablets with “501” debossed on one side and plain on the other side | Bottle / 30 count | NDC 57664-501-83 |
| Bottle / 1000 count | NDC 57664-501-18 |
Storage
Store at 20° to 25°C (68° to 77°F); excursions permitted 15° to 30°C (59° to 86°F). [see USP Controlled Room Temperature]. Protect from light and moisture.
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