Clarithromycin

What is clarithromycin?

Clarithromycin (brand name: Biaxin®) is a macrolide antibiotic used to treat certain bacterial infections, such as Helicobacter species and Rhodococcus equi in foals.

Its use in cats, dogs, ferrets, and horses, to treat bacterial infections, is “off label” or “extra label”. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.

How is clarithromycin given?

• Clarithromycin is given by mouth in the form of a tablet or liquid suspension.
• It may be given with or without food. If gastrointestinal problems occur, give future doses with food. 
• Measure liquid forms carefully and shake well before use.

This medication should take effect within 1 to 2 hours, and while effects may not be obvious, gradual improvements are usually noticeable after a few days.

What if I miss giving my pet the medication?

If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. If it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.

Are there any potential side effects?

Side effects seem uncommon, although information is currently limited in domestic animals. Possible side effects include:

• diarrhea, vomiting, and appetite changes
• stomach pain and cramps 

In cats, side effects may include:

• ear redness or generalized skin redness

Serious side effects may occur. If any of the following signs develop, contact your veterinarian immediately:

• collapse
• severe sleepiness
• bloody diarrhea
• yellowing of the skin, gums, or eyes

It is unknown if there are rare effects in pets. In humans, rare effects have occurred, such as liver problems, decreased platelets (the blood cells involved in blood clotting), and allergic reactions. 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?

Clarithromycin should NOT BE USED in:

• pets that are allergic to it or other macrolide antibiotics
• small mammals such as rabbits, gerbils, guinea pigs, or hamsters
• adult horses

Clarithromycin should be USED WITH CAUTION in: 

• pets that are pregnant or lactating (effects are unknown)
• horses more than four months old
• horses exposed to hot weather (provide shade and close observation in these environments)

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with clarithromycin: 

• alprazolam
• amlodipine
• chemotherapy agents
• cyclosporine
• diltiazem
• fluconazole
• ketoconazole
• methylprednisolone
• midazolam
• omeprazole
• opioids
• rifampin
• sildenafil
• theophylline

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

Is any monitoring needed with this medication?

• No specific monitoring is required while your pet is taking this medication. 
• Your veterinarian may monitor your pet to be sure that the medication is working. 
• Monitor your pet at home for serious side effects.

How do I store clarithromycin?

• Store tablets at room temperature, between 68°F and 77°F (20°C and 25°C).
• Store tablets in a tightly closed container, away from light.
• Do not refrigerate the liquid suspension; store at room temperature and discard after 14 days.

What should I do in case of 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.