Most cats start showing increased interest in food within 1 to 3 days of starting Mirataz, though some owners notice a difference in as little as a few hours after the first application. Mirataz is a transdermal ointment containing mirtazapine, applied to the inner ear to stimulate appetite in cats who have stopped eating or are losing weight. The FDA-approved treatment course is 14 days of daily use, and measurable weight gain typically follows within that window.
What to Expect in the First Few Days
Because Mirataz is absorbed through the skin rather than swallowed as a pill, it takes some time for mirtazapine to build up in your cat’s bloodstream. Most cats begin eating more within the first 1 to 3 days. Some respond faster, showing interest in food the same day, while others take the full first week before appetite noticeably picks up. If your cat hasn’t shown any improvement in eating after about 4 to 5 days of consistent daily application, that’s worth a conversation with your vet.
The drug works on two fronts. It blocks certain receptors in the brain that suppress appetite, encouraging your cat to feel hungry. It also blocks receptors involved in nausea, which is especially helpful for cats with kidney disease or other conditions that cause queasiness. That anti-nausea effect can kick in relatively quickly, sometimes making a cat more willing to approach food before their overall appetite fully rebounds.
Weight Gain Over the 14-Day Course
The standard Mirataz protocol is a 1.5-inch ribbon of ointment applied to the inner ear once daily for 14 days. While appetite often picks up in the first few days, visible weight gain takes longer. Most cats show meaningful weight recovery over the full two-week treatment period. Don’t expect dramatic changes on the scale after just a few days. The early wins are behavioral: your cat walking to the food bowl, eating more of what’s offered, or showing interest in treats again.
After the 14 days are up, monitor your cat’s food intake closely. Appetite can drop once the medication stops. If your cat’s food intake drops by more than 75% for several days, or if they stop eating entirely for more than 48 hours after discontinuation, they need to be reevaluated by a vet. Some cats end up on longer or repeated courses depending on their underlying condition.
How to Apply Mirataz Correctly
Proper application makes a real difference in how well and how quickly the drug works. You’ll apply the ointment to the inner pinna, the smooth, hairless flap of your cat’s outer ear. Alternate ears with each dose, applying to the left ear one day and the right ear the next. Before each application, clean the ear with water or a gentle ear cleaning solution to remove any residue from the previous dose.
Alternating and cleaning serves two purposes: it reduces skin irritation at the application site and helps the drug absorb consistently. Wear gloves when applying Mirataz, since mirtazapine can absorb through human skin as well. After application, try to prevent your cat from scratching at the ear or shaking the ointment off for a few minutes while it absorbs.
Common Side Effects
Mirataz is generally well tolerated, but some cats show behavioral changes while on it. Your cat may vocalize more than usual, becoming more talkative or yowling at odd times. Hyperactivity is another common reaction, with some cats seeming unusually restless or agitated, particularly in the hours after application. These effects tend to be mild and temporary.
Skin irritation on the inner ear is another possibility, which is one reason alternating ears and cleaning before each dose matters. Redness or flaking at the application site usually resolves once you switch to the other ear. If irritation becomes severe or your cat is excessively scratching at their ears, let your vet know.
Important Drug Interactions
Mirataz should not be used in cats currently taking certain other medications. Cats who have been on a type of drug called an MAOI need at least a 14-day washout period before starting Mirataz, because combining them raises the risk of serotonin syndrome, a potentially dangerous condition caused by too much serotonin activity in the body. The same applies to tramadol (a pain medication) and cyproheptadine (another appetite stimulant that works differently). If your cat is on any of these, your vet will need to plan the timing carefully before switching to Mirataz.
Why Some Cats Respond Faster Than Others
Several factors influence how quickly your cat responds. Cats with mild appetite loss from a short illness often bounce back faster than cats with advanced kidney disease or cancer who have been eating poorly for weeks. A cat’s overall body condition, hydration status, and whether nausea is a major component all play a role. The underlying condition matters too: if the disease itself is causing food aversion through pain or nausea, Mirataz can only do so much on its own, and treating the root cause alongside the appetite stimulant gives the best results.
Absorption can also vary. If ointment gets rubbed off before it’s absorbed, or if the ear isn’t cleaned before reapplication, your cat may not get the full dose. Consistent, correct application at roughly the same time each day helps the drug reach effective levels in the bloodstream and stay there.