Feline Health Topics for veterinarians Summer 1992 Volume 7, Number 3 Part II: Drugs Useful In Feline Practice Lauren A. Trepanier, D.V.M., D.A.C.V.I.M. Editor’s Note: The first part of this two-part series therapy in most diabetic cats. However, it is not covered drugs usefulfor gastrointestinal, respiratory, potent enough to resolve ketoacidosis efficiently; in circulatory, and multisystem problems. The drugs ketotic patients, regular insulin should be used described in this article include some commonly used initially. Side effects include hypoglycemia and and some that are recently introduced that may be inadequate control of hyperglycemia. useful to the feline practitioner. Many of these drugs Drug formulation: U 100 (100 U/ml) have not been approved for use in cats, and therefore must be used as an extra-label or experimental drug. Dosage: 1 to 3 units SQ once daily to start; adjust Very few have been evaluated with pharmacokinetic dose and frequency based on glucose profiles or efficacy studies, and therefore many doses are empirical. Glipizide (Glucotrol) As a sulfonylurea oral hypoglycemic agent, Diabetes glipizide increases insulin release from pancreatic Ultralente insulin beta cells, increases the number and sensitivity of This is a zinc-containing, long-acting insulin. A insulin receptors, and decreases hepatic gluconeo- single daily dose can provide maintenance insulin genesis. It is useful in treating mild-to-moderate persistent hyperglycemia in diabetic cats without ketosis. It may also be useful in cats that are insulin resistant due to obesity or whose owners cannot give Inside this issue.. injections but can carefully monitor their cats. Other drugs (eg. other sulfas, salicylates) that can displace glipizide from protein binding sites Drugs Useful in Feline Practice page 1 may increase the hypoglycemic effects. Glipizide is contraindicated for ketotic patients or those with Cat's Meow page 5 complete pancreatic beta-cell failure (i.e. un­ detectable insulin levels). Reported side effects are Evaluation of hypoglycemia (usually one to two months into Primucell-FIP® page 6 therapy), vomiting, and reversible increases in ALT. Drug formulation: 5 and 10 mg. tablets Dosage: 5 mg. PO BID Feline Health Topics 2 Antibacterial/Antiprotozoal/Antifungal Drug formulation: 25, 75, 150 mg. tablets Metronidazole (Flagyl) Dosage: for toxoplasmosis— 12.5 mg/kg BID 2 Metronidazole is an antiprotozoal drug with an to 6 weeks; other infections— 5 to 10 mg/kg BID excellent spectrum against anaerobic bacteria. Ticarcillin plus clavulanate potassium (Timentin) Metronidazole and related compounds may also be used to sensitize cancer cells to radiation. Its This drug is a semisynthetic, antipseudomonal immunosuppressive effects may reduce inflammation penicillin with B-lactamase inhibition. It is two to in some types of inflammatory bowel disease. four times more active against Pseudomonas sp. than carbenicillin. It achieves good tissue levels in bile, Metronidazole is an effective drug in treating pleural fluid, joints, and the pericardial sac; but poor giardiasis, anaerobic infections such as pyothorax, levels in the CNS, eye and leukocytes. Because it has cholangiohepatitis, and clostridial enterocolitis; an excellent gram-negative spectrum, it is very useful inflammatory bowel disease refractory to prednisone; for treating serious gram-negative infections (i.e. CNS abscesses; and for anaerobic sterilization of the pyelonephritis causing renal failure, bacterial gut in hepatic encephalopathy. endocarditis, pneumonia, peritonitis, sepsis in Elixirs with alcohol should not be administered neutropenic chemotherapy patients). Doses should concurrently with metronidazole since the com­ be decreased in renal failure. It is contraindicated in bination can lead to vomiting and weakness. patients with a history of allergic reactions to Metronidazole is teratogenic in rodents. Side effects penicillins or cephalosporins of any kind. include anorexia and vomiting. Neurotoxicity (cerebellar ataxia, vestibular signs, seizures, tremors, \ proprioceptive deficits) have been reported in dogs with doses as low as 70 mg/kg/day. Feline Health Topics Drug formulation: 250 mg. tablets A publication for veterinary professionals Dosage: 15 to 30 mg/kg/day The ultimate purpose of the Cornell Feline Health Center is to improve the health of cats everywhere, by developing methods Clindamycin (Antirobe to prevent or cure feline diseases, and by providing continuing J education to veterinarians and cat owners. All contributions are tax-deductible. This drug acts on bacteria by suppressing Director: Fredric W. Scott, D.V.M., Ph.D. Assistant Director: James R. Richards, D.V.M. ribosomal protein synthesis in susceptible Editor: Ju n e E. T u ttle Secretaries: Sheryl A. Thomas, Gwen Frost, anaerobes and gram-positive cocci. It has good Julie Elzer tissue penetration into macrophages, leukocytes, This publication is made possible, in part, by abscesses and bone. It also has antiprotozoal a grant from 9-Lives Cat Foods. We grate­ fully acknowledge this interest and support activity against Toxoplasma gondii. Therefore, in the furthering of feline health. This it can be used to treat systemic toxoplasmosis acknowledgement of our gratitude is not an endorsement of any particular company or and aerobic and anaerobic infections (i.e. lung pro d u ct. abscesses, osteomyelitis, bite wound abscesses). ©1992 by Cornell University on behalf of the Cornell Feline Health Center, College of Side effects include anorexia, vomiting, and Veterinary Medicine, Ithaca, NY 14853. All diarrhea. Avoid concurrent usage with chlor­ rights reserved. Permission to reprint se­ lected portions must be obtained in writing. amphenicol or erythromycin as they may Cornell University is an equal opportunity, ^ affirmative action educator and employer. interfere with the efficacy of clindamycin or © show cross-resistance. Printed on recycled paper. 3 The drug has been known to cause allergic cryptococcosis, systemic mycoses, and ringworm reactions, and may exacerbate coagulopathies, (especially cases that are refractory to griseofulvin). although this is rarely of clinical significance. Although it can be used for canine Cushing’s disease, there is no reported efficacy in feline hyperadren- Drug formulation: 3.1 gram vials ocorticism. Dosage: 50 mg/kg TID-QID IV or IM Absorption of ketoconazole is decreased by Trimethoprim-sulfa (Tribrissen) antacids (cimetidine, aluminum hydroxide) since ketoconazole requires acid for dissolution and Sulfa drugs inhibit folate synthesis, which in turn absorption. Avoid high doses prior to surgery as this prevents bacterial DNA and RNA synthesis. The drug decreases the ability to release cortisol in combination of trimethoprim and a sulfonamide is response to stress. Side effects include a transient bactericidal, but the optimal ratio is 20:1 increase in AST activity, anorexia, vomiting, diarrhea, (sulfa:trimethoprim), not 5:1 as the drug is formulated. and idiosyncratic hepatotoxicity. Trimethoprim-sulfa is useful for treating bacterial meningitis, resistant urinary tract infections, otitis Drug formulation: 200 mg. tablets interna, pneumonia, neutropenia in cancer patients, Dosage: for cryptococcosis— 10 to 20 mg/kg nocardiosis (often causing pyothorax), and daily or divided BID for 5 to 6 months; for salmonellosis associated with enterocolitis and ringworm— 4 to 8 mg/kg/day for 4 to 8 weeks systemic illness. It has limited efficacy against toxoplasmosis. Anticonvulsants Diazepam (Valium) This drug is contraindicated in animals with prior history of sulfa allergy. In cases of renal failure, As a benzodiazepine drug, diazepam causes decrease the dosage or dose frequency. sedation, hypnosis, muscle relaxation, decreased anxiety, and decreased seizure activity. Diazepam Side effects include salivation, occasional works by enhancing the action of gamma- vomiting in cats, immune-mediated blood dyscrasias, aminobutyric acid (GABA), an inhibitory neuro­ allergic reactions, andrarely folate deficiency causing transmitter in CNS. Because diazepam works only nonregenerative anemia (only with high doses for via endogenous GABA levels, it has fewer sedative extended periods, e.g. when used for Nocardia effects than barbiturates. infections). Intravenous diazepam is the drug of choice for Drug formulations: 60,120,240,480 & 960 mg. status epilepticus. In cats, but not dogs, it is also tablets; 24% injectable SQ; 96 mg/ml IV effective as an oral anticonvulsant. Diazepam is also Dosage: for infections— 15 mg/kg BID or 30 effective for behavioral problems, such as spraying mg/ kg once daily; for nocardiosis— 45-60 mg/ or psychogenic alopecia. It should not be used for kg BID for 3 to 6 months seizures caused by hepatic encephalopathy or ivermectin overdose. Side effects include Ketoconazole (Nizoral) oversedation, ataxia, bradycardia, and respiratory depression. This drug is fungistatic, not fungicidal. It inhibits various P450 enzymes, thus impairing fungal cell Drug formulations: 2, 5, and 10 mg. tablets; 5 wall synthesis. Ketoconazole also impairs cortisol mg/ml injectable and androgen synthesis. It is useful for treating Feline Health Topics 4 containing compounds in the urine and may be prone Dosage: for status epilepticus— 0.2-0.5 mg/kg to a relative carnitine deficiency. IV, up to three doses; for seizure maintenance therapy— 0.5-2.0 mg/kg PO divided TID; for Drug formulation: 250 mg. capsules psychogenic alopecia— 0.25-0.5 mg/kg PO BID Dosage: for hepatic lipidosis—