By Rania Gollakner, BS, DVM, MPH

What is minocycline?

Minocycline (brand names Minocin®, Solodyn®, Arestin®) is a tetracycline-based antibiotic. It is used to treat a variety of bacterial infections in cats and dogs. It is sometimes used in place of doxycycline (Vibramycin®). Minocycline is frequently used as part of the heartworm adulticide treatment protocol and is used to treat certain tick-borne infections, such as Lyme disease.

Its use in dogs and cats is ‘off-label’. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully.

How is minocycline given?

Minocycline is given by mouth. It is available as capsules, tablets, and flavored oral suspension. It can be given with or without food but works best if able to give on an empty stomach. If your pet seems sick or vomits after giving this medication, try giving the next dose with food.

It is important not to give this medication as a dry pill. Give with a moist treat or a small amount of liquid. This is especially important in cats. If the pill becomes lodged in the throat or esophagus, it may cause ulcers.

This medication will take effect in one to two hours but outwardly effects may take a few days to be recognized.

What if I miss giving my pet the medication?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

The most commonly observed side effects are nausea, vomiting, reduced appetite, and diarrhea. If these side effects are severe or worsen, contact your veterinarian.

It is important to never dry pill a cat if using capsules or tablets, as esophagitis (damage to the esophagus, the muscular tube that delivers food from the mouth to the stomach) can occur. If your pet appears to have trouble swallowing or eating, contact your veterinarian immediately.

"If your pet appears to have trouble swallowing or eating, contact your veterinarian immediately."

Minocycline may increase your pet’s sensitivity to the sun, as this effect has been noted in humans. If you notice that hairless areas (e.g., nose, eyelids, ears) are getting sunburned or reddening, contact your veterinarian.

Rare but serious side effects may also occur, such as liver issues or ear problems, and may cause severe gastrointestinal effects, yellowing of the skin or eyes, weakness, lethargy, or loss of hearing. Long-term use of this medication may lead to superinfections of other types of bacteria or fungus.

This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Minocycline should not be used in animals that have a hypersensitivity (allergy) to it or drugs like it (e.g., doxycycline, tetracycline). It should not be used in breeding, pregnant, or nursing pets except when absolutely necessary. This medication should be used with caution in pets with a history of liver problems, pets that are young and still developing bones and teeth, and pets with certain types of kidney failure.

Are there any drug interactions I should be aware of?

If your pet is taking oral antacids, bismuth (Pepto-Bismol®), or gastro protectants (e.g., sucralfate, brand name Carafate®), the absorption or effectiveness of minocycline can be reduced. Your veterinarian may advise you to give your pet the minocycline one to two hours before or after these other medications. Other medications, such as digoxin (Lanoxin®, Cardoxin®), oral iron or zinc, penicillins, and warfarin (Coumadin®) may interfere with minocycline.

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this medication?

There is no specific monitoring that needs to be done while your pet is taking this medication. Your veterinarian may monitor your pet to be sure that the medication is working.

How do I store minocycline?

Store minocycline in a tightly sealed container at room temperature (20°C-25°C or 68°F-77°F) and protected from light.

What should I do in case of an emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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