Mirtazapine

Indications

Mirataz is indicated for body weight gain in cats with a history of weight loss.

Dosage and Administration

Administer topically by applying a 1.5-inch ribbon of ointment (approximately 2 mg/cat) on the inner pinna of the cat's ear once daily for 14 days (see Diagrams below ). Wear disposable gloves when applying Mirataz. Dispose of used gloves after each application. Alternate the daily application of Mirataz between the left and right inner pinna of the ears. Do not administer into the external ear canal. If desired, the inner pinna of the cat's ear may be cleaned by wiping with a dry tissue or cloth immediately prior to the next scheduled dose. If a dose is missed, apply Mirataz the following day and resume daily dosing. To demonstrate the method of administering the dose, the veterinarian or trained personnel at the clinic should apply the first dose in the presence of the owner. This ruler measures 1.5 inches. Use this ruler to measure the 1.5 inch ribbon of ointment to be applied. To apply Mirataz: Step 1: Wear disposable gloves. Twist cap on tube counterclockwise to open. Step 2: Apply even pressure on tube and squeeze a 1.5-inch line of ointment onto your gloved finger using the measured line on the carton or in this package insert. Step 3: Using your gloved finger, gently rub ribbon of ointment on inside pinna of the cat's ear spreading it evenly over the surface. Dispose of used gloves after each application. If contact with your skin occurs wash thoroughly with soap and warm water. Ruler Diagram Step 1 Diagram Step 2 Diagram Step 3

Contraindications

Mirataz is contraindicated in cats with a known hypersensitivity to mirtazapine or to any of the excipients. Mirataz should not be given in combination, or within 14 days before or after treatment with a monoamine oxidase inhibitor (MAOI) [e.g. selegiline hydrochloride (L-deprenyl), amitraz], as there may be an increased risk of serotonin syndrome. HUMAN WARNINGS: Not for human use. Keep out of reach of children. Wear disposable gloves when handling or applying Mirataz to prevent accidental topical exposure. After application, dispose of used gloves and wash hands with soap and water. After application, care should be taken that people or other animals in the household do not come in contact with the treated cat for 2 hours because mirtazapine can be absorbed transdermally and orally. However, negligible residues are present at the application site and the body of the cat at 2 hours after dosing. In case of accidental skin exposure, wash thoroughly with soap and warm water. In case of accidental eye exposure, flush eyes with water. If skin or eye irritation occurs seek medical attention. In case of accidental ingestion, or if skin or eye irritation occurs, seek medical attention.

Precautions

Do not administer orally or to the eye. Use with caution in cats with hepatic disease. Mirtazapine may cause elevated serum liver enzymes (See Animal Safety ). Use with caution in cats with kidney disease. Kidney disease may cause reduced clearance of mirtazapine which may result in higher drug exposure. Upon discontinuation of Mirataz, it is important to monitor the cat's food intake. Food intake may lessen after discontinuation of mirtazapine transdermal ointment. If food intake diminishes dramatically (>75%) for several days, or if the cat stops eating for more than 48 hours, reevaluate the cat. Mirataz has not been evaluated in cats < 2 kg or less than 6 months of age. The safe use of Mirataz has not been evaluated in cats that are intended for breeding, pregnant, or lactating cats.

Adverse Reactions

In a randomized, double-masked, vehicle-controlled field study to assess the effectiveness and safety of mirtazapine for the management of weight loss in cats, 115 cats treated with Mirataz and 115 cats treated with vehicle control were evaluated for safety. The vehicle control was an ointment containing the same inert ingredients as Mirataz without mirtazapine. The most common adverse reactions included application site reactions, behavioral abnormalities (vocalization and hyperactivity), and vomiting. The adverse reactions observed in the study and number of cats experiencing each adverse reaction is summarized in Table 1 below. Table 1. Adverse Reactions Reported During the Field Study Adverse Reaction Mirataz N=115 (%) Vehicle Control N=115 (%) Application site (Ear pinna) Erythema 12 (10.4%) 20 (17.4%) Crust/Scab 3 (2.6%) 6 (5.2%) Residue 3 (2.6%) 8 (7.0%) Scaling/Dryness 3 (2.6%) 3 (2.6%) Dermatitis or irritation 1 (0.9%) 9 (7.8%) Alopecia 1 (0.9%) 2 (1.7%) Pruritus 1 (0.9%) 4 (3.5%) Behavioral Vocalization 13 (11.3%) 2 (1.7%) Hyperactivity 8 (7.0%) 1 (0.9%) Disoriented state or ataxia 4 (3.5%) 2 (1.7%) Lethargy/weakness 4 (3.5%) 9 (7.8%) Attention Seeking 3 (2.6%) 0 Aggression 2 (1.7%) 0 Physical Examination or Observational Vomiting 13 (11.3%) 15 (13.0%) Dehydration 6 (5.2%) 5 (4.3%) Diarrhea or soft stool 6 (5.2%) 7 (6.1%) Heart murmur 5 (4.3%) 7 (6.1%) Inappetence 5 (4.3%) 5 (4.3%) Renal insufficiency One cat with renal insufficiency was reported with a serious adverse reaction of acute renal failure, hematuria, and pyuria at the Week 2 visit. The cat was enrolled with a history of chronic kidney disease. Euthanasia was elected and necropsy revealed hypertrophic cardiomyopathy, bilateral parathyroid hyperplasia, and mild to moderate renal disease. 4 (3.5%) 0 Ear infection 3 (2.6%) 0 Urinary tract infection 3 (2.6%) 0 Clinical Pathology Hematuria 7 (6.1%) 1 (0.9%) Elevated BUN (without creatinine) At Week 2, blood urea nitrogen (BUN) values were significantly higher in the Mirataz group compared to the vehicle control group (p<0.10). The BUN in the Mirataz group was 43.60 mg/dL (reference range 16-37 mg/dL) compared to 36.05 mg/dL in the vehicle control group. 6 (5.2%) 0 Elevated creatinine and BUN 5 (4.3%) 1 (0.9%) Hyperphosphatemia 5 (4.3%) 0 Hypokalemia 5 (4.3%) 2 (1.7%) Pyuria 5 (4.3%) 0 Anemia 3 (2.6%) 8 (7.0%) Low urine specific gravity 3 (2.6%) 1 (0.9%) Monocytosis 3 (2.6%) 2 (1.7%) Neutrophilia 3 (2.6%) 2 (1.7%) Post study, follow-up was done in 199 cats (103 in the Mirataz (mirtazapine transdermal ointment) group and 96 in the vehicle control group). Following cessation of Mirataz, four cats were reported as being less social or less restless, one cat was reported as more active, and one cat was reported with increased hissing and urinating out of the litter box. To report suspected adverse events, for technical assistance or to obtain a copy of the SDS, contact Dechra at (866) 933-2472. For additional information about adverse drug experience reporting for animal drugs, contact FDA at 1-888-FDA-VETS or online at http://www.fda.gov/reportanimalae

Description

Mirataz (mirtazapine transdermal ointment) is a white to off-white ointment containing 2% (w/w) of mirtazapine suitable for transdermal (topical) administration. Mirataz contains the following inactive ingredients: Polyethylene Glycol (PEG) 400, PEG 3350, Diethylene Glycol Monoethyl Ether, PEG-8 Caprylic/Capric Glycerides, Oleyl Alcohol, Butylated Hydroxytoluene, Dimethicone, and Dry Flo TS. The structural formula of mirtazapine is: Molecular Formula: C 17 H 19 N 3 Molecular Weight: 265.35 Chemical Structure

Information for Owners

Upon discontinuation of Mirataz, it is important to monitor your cat's food intake. Your cat's food intake may lessen after discontinuation of mirtazapine transdermal ointment. If food intake diminishes dramatically (>75%) for several days or if your cat stops eating for more than 48 hours, contact your veterinarian.

Storage

Store below 25°C (77°F). Multi-use tube. Discard within 30 days of first use.

FDA adverse event reports

The FDA Center for Veterinary Medicine publishes the adverse event reports it receives through openFDA. The counts below are the reports naming mirtazapine as an active ingredient for each species this label names, as returned on 2026-09-16, coded by the VeDDRA reaction term the reporter chose. Reactions are counted per report, so one report can appear under several terms.

These are counts, not rates. Reporting is voluntary, the number of animals treated is not known, and a widely used product accumulates reports for that reason alone. A report records that an event followed a dose; it does not establish that the product caused it. The counts say nothing about how one product compares with another.