Furosemide/MethimAZOLE Transdermal Pen (9mL)
Furosemide/MethimAZOLE is a compounded formulation containing Furosemide, MethimAZOLE, prepared by Mixlab for veterinary use. Available by prescription.
A transdermal pen is a simple way to give your pet medicine through their skin—usually used for cats by applying gel to the inside of their ear.
Step-by-Step:
- Get the pen ready – Twist the pen to dispense a small amount of gel. If it’s your first time, you will need to “prime” it first (the gel should be flush with the edge of the tip)
- Wear gloves – Always use a disposable glove or finger cot so the medication doesn’t absorb into your skin.
- Twist to dose – Follow the pen’s directions (like two full twists) to get the right amount of gel out. Always click in a clockwise direction, clicking counter-clockwise will stop you
- Pick the spot – Apply to a hairless area, usually the inside of your cat’s ear. Make sure the area is clean and dry.
- Apply the gel – Dab the gel directly with the pen or use your gloved finger to rub it in gently. Avoid the ear canal.
- Let it dry – It usually dries in a minute or two. Try to keep your pet from rubbing it off.
- Recap the pen – This keeps the medication fresh.
- Wash your hands – Even if you wore gloves, wash thoroughly after.
- Reward your pet – A treat helps make it a stress-free routine!
- Store properly – Keep at room temp, away from sunlight. Track doses so you know when it’s time to refill.
Important: Only apply where your vet has directed—usually hairless areas. Never apply over fur or broken skin. Keep other pets from licking the area until it’s dry.
This compounded formulation combines furosemide, a loop diuretic, with methimazole, an antithyroid agent — two different drug classes. In compounding practice, clinicians may consider a combination like this for a multi-targeted approach. Your veterinarian determines whether it is appropriate based on your animal's diagnostic findings.
This description reflects the general pharmacology of the active ingredient's drug class; your veterinarian determines whether this approach is appropriate for your animal.
Prescription only. Use only under the direction of a licensed veterinarian. This information is not a substitute for veterinary diagnosis, prescribing or monitoring. Compounded drugs are not approved by the FDA for safety or effectiveness.
At a pharmacological level, methimazole manages the synthesis of thyroid hormones while furosemide manages the reabsorption of sodium and chloride in the kidneys. Commonly observed effects include behavioral shifts such as increased thirst and urination, as well as localized digestive changes like vomiting or a decrease in appetite. Because both ingredients can influence renal function and electrolyte balance, your veterinarian will monitor for observational signs of dehydration or weakness through regular blood work. Owners should monitor for significant changes in energy and contact their veterinarian promptly.
Yes. This combination of furosemide and methimazole is a prescription medication and requires a valid authorization from a licensed veterinarian. Mixlab verifies all legal authorizations.
Yes. Mixlab specializes in compounding furosemide and methimazole into customized formats, such as transdermal gels or flavored oral liquids, to support easier administration for your cat.
Veterinarians discuss this combination for cats whose hormonal condition may be complicated by heart challenges or fluid accumulation. This dual approach provides a method for managing both metabolic and cardiovascular health simultaneously.
Increased urination is a commonly observed effect of the diuretic component, furosemide. Your veterinarian will provide guidance on managing your cat's hydration and litter box access during the course of management.
Your veterinarian will recommend periodic blood work, including thyroid levels, kidney values and electrolytes. This monitoring ensures the management approach remains safe and suitable for your cat’s specific needs.
