Plasma levels of mirtazapine are linearly related to dose over a dose range of 15 to 80 mg (1.78 times the maximum recommended dose). Steady state plasma levels of mirtazapine are attained within 5 days, with about 50% accumulation (accumulation ratio=1.5). The (–) enantiomer has an elimination half-life that is approximately twice as long as the (+) enantiomer and therefore achieves plasma levels that are about 3 times as high as that of the (+) enantiomer.
Mirtazapine has an absolute bioavailability of about 50% following oral administration. Peak plasma concentrations of mirtazapine are reached within about 2 hours post dose.
The presence of food in the stomach has a minimal effect on both the rate and extent of absorption.
Mirtazapine is approximately 85% bound to plasma proteins over a concentration range of 0.01 to 10 mcg/mL.
Mirtazapine has a half-life of about 20 to 40 hours following oral administration of mirtazapine.
Mirtazapine is extensively metabolized after oral administration. Major pathways of bio-transformation are demethylation and hydroxylation followed by glucuronide conjugation. In vitro data from human liver microsomes indicate that CYP2D6 and CYP1A2 are involved in the formation of the 8-hydroxy metabolite of mirtazapine, whereas CYP3A is considered to be responsible for the formation of the N-desmethyl and N-oxide metabolite. Several unconjugated metabolites possess pharmacological activity but are present in the plasma at very low levels.
Mirtazapine and its metabolites are eliminated predominantly (75%) via urine with 15% in feces.
Following oral administration of mirtazapine tablets 20 mg/day for 7 days to subjects of varying ages (range 25 to 74 years old), oral clearance of mirtazapine was reduced in the elderly compared to the younger subjects. The clearance in elderly males was 40% lower compared to younger males, while the clearance was 10% lower in elderly females compared to younger females [see Warnings and Precautions (5.15), Use in Specific Populations (8.5)].
Male and Female Patients
The mean elimination half-life of mirtazapine after oral administration ranges from approximately 20 to 40 hours across age and gender subgroups, with females of all ages exhibiting significantly longer elimination half-lives than males (mean half-life of 37 hours for females vs. 26 hours for males).
There have been no clinical studies to evaluate the effect of race on the pharmacokinetics of mirtazapine.
Patients with Renal Impairment
When compared to subjects with normal renal function, total body clearance of mirtazapine was reduced approximately 30% in renal impaired patients with GFR=11 to 39 mL/min/1.73 m2 and approximately 50% in renal impaired patients with GFR=<10 mL/min/1.73 m2) [see Warnings and Precautions (5.15), Use in Specific Populations (8.6)].
Patients with Hepatic Impairment
Following a single 15 mg oral dose of mirtazapine, the oral clearance of mirtazapine in patients with hepatic impairment was decreased by approximately 30%, compared to subjects with normal hepatic function [see Warnings and Precautions (5.13, 5.15), Use in Specific Populations (8.6)].
Drug Interactions Studies
Mirtazapine (30 mg daily) at steady state caused a statistically significant increase (0.2) in the International Normalized Ratio (INR) in subjects treated with warfarin [see Drug Interactions (7)].
The risk of QT prolongation and/or ventricular arrhythmias (e.g., Torsades de Pointes) may be increased with concomitant use of medicines which prolong the QTc interval (e.g., some antipsychotics and antibiotics) and in mirtazapine overdose [see Warnings and Precautions (5.5), Adverse Reactions (6.1, 6.2), Drug Interactions (7), and Overdosage (10)].
In healthy male subjects (n=18), phenytoin (200 mg daily, at steady state) increased mirtazapine (30 mg daily, at steady state) clearance about 2-fold, resulting in a decrease in average plasma mirtazapine concentrations of 45% [see Drug Interactions (7)]. Mirtazapine did not significantly affect the pharmacokinetics of phenytoin.
In healthy male subjects (n=24), carbamazepine (400 mg twice a day, at steady state) increased mirtazapine (15 mg twice a day, at steady state) clearance about 2-fold, resulting in a decrease in average plasma mirtazapine concentrations of 60% [see Drug Interactions (7)].
In healthy male subjects (n=12), when cimetidine, a weak inhibitor of CYP1A2, CYP2D6, and CYP3A4, given at 800 mg b.i.d. at steady state was coadministered with mirtazapine (30 mg daily) at steady state, the Area Under the Curve (AUC) of mirtazapine increased more than 50% [see Drug Interactions (7)]. Mirtazapine did not cause relevant changes in the pharmacokinetics of cimetidine.
In healthy male Caucasian subjects (n=24), coadministration of the strong CYP3A4 inhibitor ketoconazole (200 mg b.i.d. for 6.5 days) increased the peak plasma levels and the AUC of a single 30 mg dose of mirtazapine by approximately 40% and 50%, respectively [see Drug Interactions (7)].
In healthy, CYP2D6 extensive metabolizer patients (n=32), amitriptyline (75 mg daily), at steady state, did not cause relevant changes to the pharmacokinetics of steady state mirtazapine (30 mg daily); mirtazapine also did not cause relevant changes to the pharmacokinetics of amitriptyline.
In healthy CYP2D6 extensive metabolizer subjects (n=24), mirtazapine (30 mg/day), at steady state, did not cause relevant changes in the pharmacokinetics of steady state paroxetine (40 mg/day), a CYP2D6 inhibitor.
No relevant clinical effects or significant changes in pharmacokinetics have been observed in healthy male subjects on concurrent treatment with lithium 600 mg/day for 10 days at steady state and a single 30 mg dose of mirtazapine. The effects of higher doses of lithium on the pharmacokinetics of mirtazapine are unknown.
Mirtazapine (30 mg daily) at steady state did not influence the pharmacokinetics of risperidone (up to 3 mg twice a day) in subjects (n=6) in need of treatment with an antipsychotic and antidepressant drug.
Concomitant administration of alcohol (equivalent to 60 g) had a minimal effect on plasma levels of mirtazapine (15 mg) in 6 healthy male subjects. However, the impairment of cognitive and motor skills produced by mirtazapine were shown to be additive with those produced by alcohol.
Concomitant administration of diazepam (15 mg) had a minimal effect on plasma levels of mirtazapine (15 mg) in 12 healthy subjects. However, the impairment of motor skills produced by mirtazapine has been shown to be additive with those caused by diazepam.
Carcinogenicity studies were conducted with mirtazapine given in the diet at doses of 2, 20, and 200 mg/kg/day to mice and 2, 20, and 60 mg/kg/day to rats. The highest doses used are approximately 20 and 12 times the maximum recommended human dose (MRHD) of 45 mg/day, based on body surface area (mg/m2) in mice and rats, respectively. There was an increased incidence of hepatocellular adenoma and carcinoma in male mice at the high dose. In rats, there was an increase in hepatocellular adenoma in females at the mid and high doses and in hepatocellular tumors and thyroid follicular adenoma/cystadenoma and carcinoma in males at the high dose.
Mirtazapine was not mutagenic or clastogenic and did not induce general DNA damage as determined in several genotoxicity tests: Ames test, in vitro gene mutation assay in Chinese hamster V 79 cells, in vitro sister chromatid exchange assay in cultured rabbit lymphocytes, in vivo bone marrow micronucleus test in rats, and unscheduled DNA synthesis assay in HeLa cells.
Impairment of Fertility
In a fertility study in rats, mirtazapine was given at doses up to 100 mg/kg [20 times the maximum recommended human dose (MRHD), based on body surface area (mg/m2)]. Mating and conception were not affected by the drug, but estrous cycling was disrupted at doses that were 3 or more times the MRHD, and pre-implantation losses occurred at 20 times the MRHD.
The efficacy of mirtazapine as a treatment for major depressive disorder was established in 4 placebo-controlled, 6-week trials in adult outpatients meeting DSM-III criteria for major depressive disorder. Patients were titrated with mirtazapine from a dose range of 5 mg to 35 mg/day. The mean mirtazapine dose for patients who completed these 4 studies ranged from 21 to 32 mg/day. Overall, these studies demonstrated mirtazapine to be superior to placebo on at least 3 of the following 4 measures: 21-Item Hamilton Depression Rating Scale (HDRS) total score; HDRS Depressed Mood Item; CGI Severity score; and Montgomery and Asberg Depression Rating Scale (MADRS). Superiority of mirtazapine over placebo was also found for certain factors of the HDRS, including anxiety/somatization factor and sleep disturbance factor.
Examination of age and gender subsets of the population did not reveal any differential responsiveness on the basis of these subgroupings.
In a longer-term study, patients meeting (DSM-IV) criteria for major depressive disorder who had responded during an initial 8 to 12 weeks of acute treatment on mirtazapine were randomized to continuation of mirtazapine or placebo for up to 40 weeks of observation for relapse. Response during the open phase was defined as having achieved a HAM-D 17 total score of ≤8 and a CGI-Improvement score of 1 or 2 at 2 consecutive visits beginning with week 6 of the 8 to 12 weeks in the open-label phase of the study. Relapse during the double-blind phase was determined by the individual investigators. Patients receiving continued mirtazapine treatment experienced significantly lower relapse rates over the subsequent 40 weeks compared to those receiving placebo. This pattern was demonstrated in both male and female patients.
NDC: 50090-2558-2 60 TABLET, FILM COATED in a BOTTLE
NDC: 50090-2558-3 90 TABLET, FILM COATED in a BOTTLE
NDC: 50090-2558-0 30 TABLET, FILM COATED in a BOTTLE
NDC: 50090-2800-1 90 TABLET, FILM COATED in a BOTTLE
NDC: 50090-2800-0 30 TABLET, FILM COATED in a BOTTLE
Advise the patient to read the FDA-approved patient labeling (Medication Guide).
Suicidal Thoughts and Behaviors
Advise patients and caregivers to look for the emergence of suicidality, especially early during treatment and when the dosage is adjusted up or down, and instruct them to report such symptoms to the healthcare provider [see Boxed Warning and Warnings and Precautions (5.1)].
Advise patients to contact their physician if they experience fever, chills, sore throat, mucous membrane ulceration, flu-like complaints, or other symptoms that might suggest infection [see Warnings and Precautions (5.2)].
Caution patients about the risk of serotonin syndrome, particularly with the concomitant use of mirtazapine with other serotonergic drugs including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, amphetamines, St. John’s Wort, and with drugs that impair metabolism of serotonin (in particular, MAOIs, both those intended to treat psychiatric disorders and also others, such as linezolid). Advise patients to contact their healthcare provider or report to the emergency room if they experience signs or symptoms of serotonin syndrome [see Dosage and Administration (2.4), Contraindications (4), Warnings and Precautions (5.3), Drug Interactions (7)].
QT Prolongation and Torsades de Pointes
Inform patients to consult their physician immediately if they feel faint, lose consciousness, or have heart palpitations [see Warnings and Precautions (5.5), Drug Interactions (7), Overdosage (10)]. Advise patients to inform physicians that they are taking mirtazapine before any new drug is taken.
Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)
Advise patients to report to their healthcare provider at the earliest onset of fever, rash, swollen lymph nodes, or other signs and symptoms suggestive of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) [see Contraindications (4), Warnings and Precautions (5.6)].
Advise patients that mirtazapine may impair judgment, thinking, and particularly, motor skills, because of its prominent sedative effect. Caution patients about performing activities requiring mental alertness, such as operating hazardous machinery or operating a motor vehicle, until they are reasonably certain that mirtazapine therapy does not adversely affect their ability to engage in such activities. [see Warnings and Precautions (5.8)].
Activation of Mania/Hypomania
Advise patients and their caregivers to observe for signs of activation of mania/hypomania and instruct them to report such symptoms to the healthcare provider [see Warnings and Precautions (5.9)].
Advise patients not to abruptly discontinue mirtazapine and to discuss any tapering regimen with their healthcare provider. Adverse reactions can occur when mirtazapine is discontinued [see Dosage and Administration (2.6), Warnings and Precautions (5.14)].
- Advise patients to notify their physician if they become pregnant or intend to become pregnant during mirtazapine therapy.
- Advise patients that there is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to mirtazapine during pregnancy [see Use in Specific Populations (8.1)].
Advise patients to notify their physician if they are breastfeeding an infant [see Use in Specific Populations (8.2)].
Patients should be advised that taking mirtazapine can cause mild pupillary dilation, which in susceptible individuals, can lead to an episode of angle-closure glaucoma. Pre-existing glaucoma is almost always open-angle glaucoma because angle-closure glaucoma, when diagnosed, can be treated definitively with iridectomy. Open-angle glaucoma is not a risk factor for angle-closure glaucoma. Patients may wish to be examined to determine whether they are susceptible to angle-closure, and have a prophylactic procedure (e.g., iridectomy), if they are susceptible [see Warnings and Precautions (5.4).]
For more information about mirtazapine tablets, call Rising Health, LLC at 1-833-395-6928.
Dispense with medication guide available at : http://www.risingpharma.com/med-guides.html
Rising Health, LLC
Saddle Brook, NJ 07663
Made in India
|MEDICATION GUIDE Mirtazapine Tablets, USP for oral use (mir taz’ a peen)|
| What is the most important information I should know about mirtazapine tablets? Mirtazapine tablets may cause serious side effects, including: |
|What are mirtazapine tablets? Mirtazapine tablets are prescription medicines used to treat a certain type of depression called Major Depressive Disorder (MDD) in adults.It is not known if mirtazapine tablets are safe and effective for use to treat MDD in children.|
|Who should not take mirtazapine tablets? Do not take mirtazapine tablets if you: |
|Before taking mirtazapine tablets, tell your healthcare provider about all your medical conditions, including if you: |
| How should I take mirtazapine tablets? |
| What should I avoid while taking mirtazapine tablets? |
|What are the possible side effects of mirtazapine tablets? Mirtazapine tablets may cause serious side effects, including: |
| How should I store mirtazapine tablets? |
|General information about the safe and effective use of mirtazapine tablets. Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use mirtazapine tablets for a condition for which it was not prescribed. Do not give mirtazapine tablets to other people, even if they have the same symptoms that you have. They may harm them. You can ask your healthcare provider or pharmacist for information about mirtazapine tablets that is written for healthcare professionals.|
|What are the ingredients in mirtazapine tablets? Active ingredient: mirtazapineInactive ingredients: colloidal silicon dioxide, corn starch, hydroxypropyl cellulose, hypromellose, lactose monohydrate, magnesium stearate, and titanium dioxide. In addition, the 15 mg contains iron oxide yellow and 30 mg contains iron oxide red, iron oxide black, and iron oxide yellow.For more information about mirtazapine tablets, call Rising Health, LLC at 1-833-395-6928.Dispense with medication guide available at: http://www.risingpharma.com/med-guides.html Distributed by: Rising Health, LLC Saddle Brook, NJ 07663 Made in India Code: TS/DRUGS/19/1993|
This Medication Guide has been approved by the U.S. Food and Drug Administration
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