Convenia

Convenia: Sacrificing safety for conveniency

Most cat owners know that medicating a cat can be challenging. That’s probably why many veterinarians as well as cat owners celebrated when Convenia, a long-acting, injectable antibiotic, came on the market in 2008. Convenia is manufactured by Pfizer Animal Health.

The idea of a one-time injection, instead of giving regular anitibiotics in pill or liquid form once or twice a day for two weeks or more, seemed like a great solution to the problem.

However, contrary to regular antibiotics, which are rapidly cleared from the body, Convenia stays in the body for two months or longer following injection, even though the antibacterial effects only last for two weeks. All drugs have some side effects.

While some cats may do just fine with Convenia, others may have side effects ranging from mild to life threatening. And with a long acting drug like Convenia, there is no way to simply stop giving the medication – it’s already in your cat’s system.

Amber was one of those hard-to-pill cats. After careful discussion with my vet, I agreed to use Convenia following a dental procedure, which I’ve now come to learn is an inappropriate use for this drug. At the time, I only had misgivings about it because of its long-acting properties.

Thankfully, she had no side effects other than some mild diarrhea, which is a common side effect of most antibiotics.

Dogs

CONVENIA is indicated for the treatment of skin infections (secondary superficial pyoderma, abscesses, and wounds) in dogs caused by susceptible strains of Staphylococcus intermedius and Streptococcus canis (Group G).
 

Cats

CONVENIA is indicated for the treatment of skin infections (wounds and abscesses) in cats caused by susceptible strains of Pasteurella multocida.
 

Convenia Dosage And Administration

Dogs

CONVENIA should be administered as a single subcutaneous injection of 3.6 mg/lb (8 mg/kg) body weight. A second subcutaneous injection of 3.6 mg/lb (8 mg/kg) may be administered if response to therapy is not complete. The decision for a second injection for any individual dog should take into consideration such factors as progress toward clinical resolution, the susceptibility of the causative organisms, and the integrity of the dog’s host-defense mechanisms. Therapeutic drug concentrations after the first injection are maintained for 7 days for S. intermedius infections and for 14 days for S. canis (Group G) infections. Maximum treatment should not exceed 2 injections.

Cats

CONVENIA should be administered as a single, one-time subcutaneous injection at a dose of 3.6 mg/lb (8 mg/kg) body weight. After an injection of CONVENIA, therapeutic concentrations are maintained for approximately 7 days for Pasteurella multocida infections.

General Dosing Information

A sample of the lesion should be obtained for culture and susceptibility testing prior to beginning antimicrobial therapy. Once results become available, continue with appropriate therapy. If acceptable response to treatment is not observed, or if no improvement is seen within 3 to 4 days, then the diagnosis should be re-evaluated and appropriate alternative therapy considered.

CONVENIA may persist in the body for up to 65 days. The effect of remaining concentrations of cefovecin on any subsequent antimicrobial therapies has not been determined. Fluoroquinolone and aminoglycoside antimicrobials have been reported to be compatible with cephalosporin antimicrobial agents.
 

Table 1: Dose Table For Convenia At 8 Mg/kg Body Weight.

Weight Of Animal	Volume Of Convenia (3.6 Mg/lb Or 0.045 Ml/lb)
5 lb	0.23 mL
10 lb	0.45 mL
15 lb	0.67 mL
20 lb	0.90 mL
40 lb	1.8 mL
80 lb	3.6 mL

Preparation Of Solution For Injection

To deliver the appropriate dose, aseptically reconstitute CONVENIA with 10 mL sterile water for injection. Shake and allow vial to sit until all material is visually dissolved. The resulting solution contains cefovecin sodium equivalent to 80 mg/mL cefovecin. CONVENIA is light sensitive. The vial should be stored in the original carton and refrigerated when not in use. Use the entire contents of the vial within 56 days of reconstitution.

Contraindications

CONVENIA is contraindicated in dogs and cats with known allergy to cefovecin or to β-lactam (penicillins and cephalosporins) group antimicrobials. 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).

Warnings: Not For Use In Humans. Keep This And All Drugs Out Of Reach Of Children. Consult A Physician In Case Of Accidental Human Exposure. For Subcutaneous Use In Dogs And Cats Only. Antimicrobial Drugs, Including Penicillins And Cephalosporins, Can Cause Allergic Reactions In Sensitized Individuals. To Minimize The Possibility Of Allergic Reactions, Those Handling Such Antimicrobials, Including Cefovecin, Are Advised To Avoid Direct Contact Of The Product With The Skin And Mucous Membranes.

precautions

Prescribing antibacterial drugs in the absence of a proven or strongly suspected bacterial infection is unlikely to provide benefit to treated animals and may increase the risk of the development of drug-resistant animal pathogens.

The safe use of CONVENIA in dogs or cats less than 4 months of age (see Animal Safety) and in breeding or lactating animals has not been determined. Safety has not been established for IM or IV administration.
 

The long-term effects on injection sites have not been determined. CONVENIA is slowly eliminated from the body, approximately 65 days is needed to eliminate 97% of the administered dose from the body. Animals experiencing an adverse reaction may need to be monitored for this duration.


CONVENIA has been shown in an experimental in vitro system to result in an increase in free concentrations of carprofen, furosemide, doxycycline, and ketoconazole.

Concurrent use of these or other drugs that have a high degree of protein-binding (e.g. NSAIDs, propofol, cardiac, anticonvulsant, and behavioral medications) may compete with cefovecin-binding and cause adverse reactions.

Positive direct Coombs’ test results and false positive reactions for glucose in the urine have been reported during treatment with some cephalosporin antimicrobials. Cephalosporin antimicrobials may also cause falsely elevated urine protein determinations. Some antimicrobials, including cephalosporins, can cause lowered albumin values due to interference with certain testing methods.

Occasionally, cephalosporins and NSAIDs have been associated with myelotoxicity, thereby creating a toxic neutropenia⁴. Other hematological reactions seen with cephalosporins include neutropenia, anemia, hypoprothrombinemia, thrombocytopenia, prolonged prothrombin time (PT) and partial thromboplastin time (PTT), platelet dysfunction and transient increases in serum aminotransferases.

Adverse Reactions

Dogs
A total of 320 dogs, ranging in age from 8 weeks to 19 years, were included in a field study safety analysis. Adverse reactions reported in dogs treated with CONVENIA and the active control are summarized in Table 2.

Table 2: Number Of Dogs* With Adverse Reactions Reported During The Field Study With Convenia.

Adverse Reaction	CONVENIA (n=157)	Active Control (n=163)
Lethargy	2	7
Anorexia/Decreased Appetite	5	8
Vomiting	6	12
Diarrhea	6	7
Blood in Feces	1	2
Dehydration	0	1
Flatulence	1	0
Increased Borborygmi	1	0

*Some dogs may have experienced more than one adverse reaction or more than one occurrence of the same adverse reaction during the study.

Mild to moderate elevations in serum γ-glutamyl transferase or serum alanine aminotransferase were noted post-treatment in several of the CONVENIA-treated dogs. No clinical abnormalities were noted with these findings.

One CONVENIA-treated dog in a separate field study experienced diarrhea post-treatment lasting 4 weeks. The diarrhea resolved.

Cats

A total of 291 cats, ranging in age from 2.4 months (1 cat) to 21 years, were included in the field study safety analysis. Adverse reactions reported in cats treated with CONVENIA and the active control are summarized in Table 3.

Table 3: Number Of Cats* With Adverse Reactions Reported During The Field Study With Convenia.

Adverse Reaction	CONVENIA (n=147)	Active Control (n=144)
Vomiting	10	14
Diarrhea	7	26
Anorexia/Decreased Appetite	6	6
Lethargy	6	6
Hyper/Acting Strange	1	1
Inappropriate Urination	1	0

*Some cats may have experienced more than one adverse reaction or more than one occurrence of the same adverse reaction during the study.

Four CONVENIA cases had mildly elevated post-study ALT (1 case was elevated pre-study). No clinical abnormalities were noted with these findings.
 

Twenty-four CONVENIA cases had normal pre-study BUN values and elevated post-study BUN values (37 - 39 mg/dL post-study).

There were 6 CONVENIA cases with normal pre- and mildly to moderately elevated post-study creatinine values. Two of these cases also had an elevated post-study BUN. No clinical abnormalities were noted with these findings.

One CONVENIA-treated cat in a separate field study experienced diarrhea post-treatment lasting 42 days. The diarrhea resolved.
 

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.