By Rania Gollakner, BS, DVM, MPH

What is chloramphenicol?

Chloramphenicol (brand names Chloromycetin® and Viceton®) is a broad-spectrum antibiotic used to treat many different bacterial infections, including those caused by anaerobic bacteria (bacteria that do not require oxygen for survival or growth) and Rickettsia (for example, the bacteria that causes Rocky Mountain Spotted Fever). It is approved for use in dogs but is used ‘off label’ or ‘extra-label’ in cats. 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 chloramphenicol given?blister_pack_medication

Chloramphenicol comes in tablet form, capsules, as a liquid suspension, and also in an injectable form (chloramphenicol sodium succinate). Tablets, capsules, and liquid suspension should be given by mouth with food.

The tablets are extremely bitter and even hiding the tablets in food may not cover the bitter taste. If you are having trouble giving the tablets to your pet, other forms of the medication should be tried.

Injectable forms will be administered by your veterinarian.

What if I miss giving my pet the medication?

It is very important to give the medication at the prescribed intervals. Missing a dose can cause the drug not to work properly. If you miss giving your pet a dose, give the next dose as soon as you remember, and then wait the recommended amount of time between doses. If it is close to the next scheduled dose when you remember, maintain the regular schedule. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

Vomiting, diarrhea, and anorexia (a decreased appetite) are quite common side effects. With prolonged treatment, bone marrow function can be affected. Chloramphenicol should be used with caution or avoided in animals with blood disorders, such as anemia. Dogs may experience weakness and lack of muscle coordination of resulting in difficulty walking. Cats are much more sensitive and more susceptible to experiencing side effects of this drug.

Are there any risk factors for this medication?

Chloramphenicol should be used with caution in animals with liver or kidney disease. Chloramphenicol should not be administered to dogs used for breeding, or in pregnant females. Its use should be avoided in very young or very old animals. Pets should not be vaccinated while taking this medication.

NOTE: Exposure in humans can have severe consequences that are irreversible, so care must be taken to avoid accidental exposure. Gloves should be worn when handling the medication. DO NOT crush pills as inhaling the drug is just as dangerous as touching or consuming it – crushing the pills creates powders that can become airborne. If your pet vomits after giving this drug, wear gloves while cleaning up.

Are there any drug interactions I should be aware of?

Caution must be taken when chloramphenicol is used in conjunction with many anaesthetics, barbiturates (e.g., phenobarbital), salicylates (e.g., aspirin), and some other antibiotics (e.g., penicillins, cephalosporins). 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?

Monitoring of the levels of drug in the blood may be recommended by your veterinarian. This ensures that the correct amount of medication is being administered. If long-term use is expected, blood tests, including complete blood counts, may be necessary before treatment begins and every two days during the treatment.

How do I store chloramphenicol?

Store chloramphenicol in a tightly sealed container, protected from light, and at room temperature.

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.

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