Clindamycin Hydrochloride (Clindadrops, Antirobe, Cleosin)

Date Published: 02/20/2002
Date Reviewed/Revised: 01/08/2020

(For veterinary information only)

The size of the tablet/medication is NOT an indication of a proper dose. Never administer any drug without your veterinarian's input. Serious side effects or death can occur if you use drugs on your pet without your veterinarian's advice.

Brand Name: Clindadrops, Antirobe, Cleosin

Available in 25 mg, 75 m, 150 mg, 300 mg capsules and tablets


The continuing fight against bacterial infections involves developing antibiotics capable of harming bacterial cells without damaging the patient’s cells. Biological properties that bacteria do not share with animals have been exploited to accomplish exactly this.

DNA double helix. (Photocredit: NIH Public Image Library)

Clindamycin is an antibiotic of the lincosamid class and possesses similar properties to its sister compound lincomycin. To understand how the lincosamides work, it is important to understand how proteins are made by cells. The blueprint or code for any protein structure comes from the cell’s DNA. DNA is basically a sequence of molecules that corresponds to a sequence of amino acids, and when these amino acids are strung up in order according to the DNA code, a specific protein is formed. To get from a strand of DNA to a strand of amino acids, the DNA code must be transcribed onto a strand of messenger RNA that is in turn read by a cell organ called a ribosome. The ribosome is the key player in the lincosamide antibiotic story as animal ribosomes turn out to be different from bacterial ribosomes. Because of this difference in ribosome structure, the lincosamide antibiotic is able to destroy the bacterial ribosome without affecting the animal ribosome. In this way, bacteria are not able to manufacture the proteins they need to divide and/or survive yet the patient's ability to make protein is unharmed. Depending on how much antibiotic is used, the bacterial cell may simply be inhibited from reproducing or may be killed outright.

How this Medication is Used

The Gram positive cell wall takes up purple stain. Cocci are round bacteria. The Gram positive cocci in this picture appear as purple dots. (Photo credit: CDC Public Health Image Library)

The lincosamide antibiotics seem to be most useful against the bacteria classified as Gram positive cocci (classified thus based on their shape and cell wall properties). Clindamycin is also helpful against protozoans such as toxoplasma and mycoplasma as well as many anaerobic (growing without oxygen) bacteria.

The types of bacteria sensitive to clindamycin makes this drug especially popular for use in oral and periodontal infections, skin infections, and bone infections.

Side Effects

Oral clindamycin tastes unpleasant and may be rejected by some patients.

The most common side effect of clindamycin is diarrhea, which is generally not serious and can be eased by providing probiotics or a prebiotic meal an hour after giving the medication.

More seriously, clindamycin can burn the esophagus if a tablet or capsule sticks there. For this reason, a syringe of water or some food should be used to "chase" the medication. In the event of an esophageal burn, the patient will lose appetite, develop difficulty swallowing, or may have bloody diarrhea.

Interactions with other Drugs

Erythromycin, another antibiotic, and clindamycin will be less effective in combination than when used separately. There is some evidence that the same is true when clindamycin is combined with chloramphenicol.

Clindamycin will reduce blood levels of cyclosporine when the two are used concurrently.

Concerns and Cautions

Oral clindamycin is absorbed into the body faster if given on an empty stomach, but may be given with or without food.

Clindamycin will cross the placenta if used in pregnant patients. It will also readily be transferred to nursing young and can induce diarrhea.

Dosage may need to be altered in patients with kidney or liver disease. In these cases, a different drug might be a better choice. If this is not possible, it may be helpful to measure blood levels of clindamycin to be sure the patient is able to clear the drug adequately and does not overdose.

Liver enzyme blood tests often elevate with the use of clindamycin. This is not felt to be of health significance but is important to recognize when it is seen.

The manufacturer recommends blood tests of liver and kidney function if clindamycin is to be used beyond 30 days.

This medication is not safe for use in horses, rabbits, rodents, or ruminants.

Clindamycin oral liquid is famous for its especially bitter taste. Refrigerating the medication seems to alleviate some of this unpleasant flavoring, though the manufacturer recommends storage at room temperature. Clindamycin liquid does not require refrigeration for storage.

Clindamycin tablets may stick in the esophagus on the way down and cause irritation that can lead to potentially serious scarring. This is unlikely to occur except in very small patients, but smaller pets should be given a syringe of water after their pill to assure that the tablet arrives in the stomach properly.

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