Convenia Can Have Serious and Fatal Side Effects


Active member
Mar 13, 2014
New Hampshire
Convenia (manufactured by Zoetis) is an injectable long-acting antibiotic that is labeled for the treatment of skin infections in cats and dogs. It exerts its antibacterial effects for approximately 1-2 weeks but stays in the body for over 2 months.

This is in contrast to antibiotics that are rapidly cleared from the body and need to be administered 1 - 2 times per day.

Given how difficult it is to medicate some cats, this 'long-acting' property sounds great, right?

Unfortunately, the old adage, "If it sounds too good to be true, it probably is", rings very true with respect to the use of Convenia in some cases.

Most people are aware of the fact that all drugs have potential side effects with some being more significant/life-threatening than others so we need to be mindful of these side effects when any chemical is put into a living being, not just Convenia.

That said, with regard to Convenia, it is important to consider the fact that if a patient has an adverse reaction to Convenia there is no way to retrieve this long-acting drug from his body.

If an adverse reaction occurs after a short-acting drug is administered, the patient has a much greater chance of living through the event (if other than acute anaphylaxis) because the body will clear the offending drug, hopefully, within hours - not months, as is the case with Convenia.

Note what is stated on the Drug Insert

Anaphylaxis has been reported with the use of this product in foreign market experience. If an allergic reaction or anaphylaxis occurs, CONVENIA should not be administered again and appropriate therapy should be instituted. Anaphylaxis may require treatment with epinephrine and other emergency measures, including oxygen, intravenous fluids, intravenous antihistamine, corticosteroids, and airway management, as clinically indicated.

Adverse reactions may require prolonged treatment due to the prolonged systemic drug clearance (65 days).

FOREIGN MARKET EXPERIENCE: The following adverse events were reported voluntarily during post-approval use of the product in dogs and cats in foreign markets: death, tremors/ataxia, seizures, anaphylaxis, acute pulmonary edema, facial edema, injection site reactions (alopecia, scabs, necrosis, and erythema), hemolytic anemia, salivation, pruritus, lethargy, vomiting, diarrhea, and inappetance.

The most common reactions I have read reports of are anemia, tremors/ataxia, seizures, diarrhea, lethargy, anorexia, and death.

To repeat what I said above, all drugs have side effects but it is my opinion that Convenia is being administered far too often when there are safer choices available for nearly all cases.

Dr. Andrew Jones