Mirtazapine Transdermal (Mirataz) in Cats: Lymphoma Appetite Data and 2025 Owner Survey Findings

TL;DR

Two publications now anchor mirtazapine transdermal ointment (Mirataz; 2 mg/cat applied to the inner pinna) as a validated appetite support tool in cats with chemotherapy-associated anorexia: a 2022 multi-centre retrospective study of cats with lymphoma, and a 2025 owner-survey study that provides real-world adherence and tolerability data from a broader feline population.

The lymphoma cohort: efficacy in a high-stakes context

Iorizzo et al. (Animals. 2022;12(2):155; PMC8772540; PMID 35049778) conducted a multi-centre retrospective study of transdermal mirtazapine used as an appetite stimulant and anti-emetic adjunct in 20 cats with lymphoma undergoing chemotherapy. Protocol: 2 mg applied to the inner pinna once daily for 14 days following chemotherapy administration.

Key outcomes:

• Gastrointestinal toxicity of varying grades was observed in 40% of patients — expected in a lymphoma chemotherapy population.
• Body weight improved in 60% of cats; body condition score improved in 30%; muscle condition score improved in 10%.
• The study did not find any mirtazapine-specific safety signals beyond the drug's known adverse effect profile (transient sedation, increased vocalisation).

The study is limited by its small sample size and retrospective design, but it represents the only published dataset specifically characterising mirtazapine transdermal in feline lymphoma patients receiving chemotherapy. A weight stabilisation or improvement rate of 60% in an otherwise cachectic population is clinically meaningful.

2025 owner survey: real-world adherence and tolerability

Leal et al. (Animals. 2025;15(20):3054; PMC12562069; PMID 41153979) conducted a multicentric survey-based study of 70 cat owners whose cats had been prescribed transdermal mirtazapine, published October 2025. This is the first study to systematically capture the owner perspective on this formulation.

Key findings:

• Administration ease: 97% of owners rated application to the ear as easy; 91% correctly alternated ears per manufacturer instructions.
• Efficacy: The majority of owners reported that appetite stimulation was effective in their cats. Chronic kidney disease was the most commonly cited indication.
• Adverse effects: 20% of owners reported side effects, most often increased vocalisation, pinna erythema, or restlessness — consistent with the drug's known alpha-2 antagonist and antihistamine mechanisms.
• Comparison to oral mirtazapine: Nine owners had prior experience with oral mirtazapine; most preferred the transdermal formulation for ease of administration, though cost was cited as a barrier by some.

Clinical context for practitioners

Transdermal mirtazapine is one of only two FDA-approved appetite stimulants for cats (alongside capromorelin). It avoids the stress of pilling, and its pharmacokinetics via auricular transdermal delivery are well characterised from pivotal studies.

For practitioners managing feline lymphoma patients on chemotherapy, the Iorizzo cohort supports empirical use for appetite stimulation and attenuation of chemotherapy-induced nausea and vomiting (CINV)-associated weight loss. The 2025 owner survey confirms that the transdermal route is practically achievable in most households.

Points to communicate to clients:

• The 2 mg dose is applied to the inner surface of the pinna (alternating ears daily) — not the outer pinnae or the skin of the neck.
• Onset of appetite stimulation is typically evident within 24–48 hours of first application.
• Pinna erythema at the application site is the most common local reaction and is generally mild.
• In cats with concurrent CKD (common in older lymphoma patients), dose adjustment is not required for mild-to-moderate renal impairment, but monitoring is prudent.
• The drug is dosed once daily; the 14-day tube provides exactly 14 doses. Repeat dosing is common in oncology patients for ongoing appetite support.

Voyage Clinical Desk

From clinical question to SOAP draft — cited differentials, live dose calculators, owner handouts. First answer free, no signup.

Open Voyage Clinical Desk: https://www.thevoyage.ai/forvets/ask?context=update-2026-06-06-mirtazapine-transdermal-lymphoma-cats

References

1. Iorizzo M, Valente C, Meomartino L, Fatone G, Brunetti A, Lamagna F. Appetite stimulant and anti-emetic effect of mirtazapine transdermal ointment in cats affected by lymphoma following chemotherapy administration: a multi-centre retrospective study. Animals. 2022;12(2):155. https://pmc.ncbi.nlm.nih.gov/articles/PMC8772540/
2. Leal RO, et al. Owner's perspective about the use of mirtazapine transdermal ointment in cats — a survey-based study. Animals. 2025;15(20):3054. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12562069/

Changelog

• 2026-06-06: First published.
• 2026-06-29: Added 2025 owner survey data (Leal et al.) and expanded clinical context.