Lizard Formulary - Antimicrobials

Antimicrobials

Sample all suspected infections for microscopy, culture and sensitivity. The majority of bacterial infections in lizards are by Gram-negative organisms, particularly Enterobacteriacae. Therapy may be required before the results of bacterial sensitivity tests are known.

• Aminoglycosides and quinolones are effective against most aerobic pathogens and there is little bacterial resistance to them.
• The fluoroquinolone derivative enrofloxacin is bacteriocidal (inhibit microbial DNA gyrase) and is well distributed to tissues. It is active against a wide range of Gram-negative organisms as well Gram-positives and Mycoplama spp. It is not effective against anaerobes.
• Carbenicillin and ceftazidime are good broad-spectrum antibiotics useful against anaerobes as well as most Gram-negative pathogens. If Pseudomonas spp. and anaerobes are present, ceftazidime is the most appropriate choice.

The following has also been advised: amikacin in combination with ampicillin for respiratory infections; chloramphenicol for gastrointestinal infections; an aminoglycoside in combination with a broad spectrum penicillin for general systemic infections.

• All aminoglycosides may affect neuromuscular transmission leading to muscle weakness and cause nephrotoxicity especially in reptiles kept at more than 25°C. They are also more toxic in gravid females.

Any antibiotic therapy, but particularly gentamycin, should be accompanied by fluids to maintain adequate renal function and reduce the possibility of nephrotoxicity.

Amikacin

• Potentially nephrotoxic but no published data
• Administer fluids concurrently
• Frequently used with a penicillin or a cephalosporin
• 2.5 mg/kg IM then 2.5-5 mg q72h
• 50 mg/10ml saline x 30 min nebulisation q12h
• Maintenance temperature if species POTZ unknown is 25°C

Amoxicillin

• Use with an aminoglycoside
• 20 mg/kg SC, IM q24h
• Maintenance temperature if species POTZ unknown is 26°C

Ampicillin

• May be used with an aminoglycoside
• 3-6 mg/kg PO q12-24h
• 3-10 mg/kg IM, SC q12-24h

Carbenicillin

• May be used with an aminoglycoside but at different time of day
• 400 mg/kg IM, SC q24h
• Maintenance temperature if species POTZ unknown is 30°C

Cefoperazone

• Published data in tegus
• 125 mg/kg IM q24h

Cefotaxime

• May be used with an aminoglycoside
• 20-40 mg/kg IM q24h
• 100 mg/10ml saline x 30 min nebulisation q12h

Ceftazidime

• 20 mg/kg IM q72h
• Maintenance temperature if species POTZ unknown is 30°C

Cefuroxime

• 50 mg/kg IM q48h
• Maintenance temperature if species POTZ unknown is 30°C

Cephuroxime

• 50 mg/kg IM q48h

Cephalexin

• 20-40 mg/kg PO q12h

Cephaloridine

• 10 mg/kg IM, SC q12h

Cephalothin

• 20-40 mg/kg IM q12h

Chloramphenicol

• May cause pigmentation changes in chameleons
• 20 mg/kg PO, IM, SC q12h
• 40mg/kg PO, IM, SC q24h

Chlortetracycline

• 200mg/kg PO 24h

Ciprofloxacin

• 11 mg/kg PO q48-72h

Clindamycin

• 2.5-5 mg/kg PO q12h
• 5 mg/kg PO q24h

Dihydrostreptomycin

• Administer fluids concurrently
• 5 mg/kg IM q12-24h

Dimetridazole

• 40 mg/kg PO q24h 5d

Doxycycline

• 5-10 mg/kg PO q24h 10-45d

Enrofloxacin

• 5-10mg/kg q24h PO, IM, SC, ICo
• 1-3 ml of 50 mg/250ml sterile water for nasal flush q12-24h with parenteral antibiotics

Gentamycin

• Do not use in animals over 20kg
• 2.5 mg/kg SC q72h
• 10-200 mg/15ml saline x 30 min nebulisation q12h
• Maintenance temperature if species POTZ unknown is 24°C

Kanamycin

• Administer fluids concurrently
• 10 mg/kg SC, IM, IV q24h
• Maintenance temperature if species POTZ unknown is 24°C

Lincomycin

• Potentially nephrotoxic
• Administer fluids concurrently
• 6 mg/kg q12-24h

Metronidazole

• May be administered concurrently with amikacin
• Low dose may stimulate depressed immune system
• 12.5-40 mg/kg q24h > 7d
• 100-275 mg/kg PO as a single dose

Oxytetracycline

• May produce local reaction at injection site
• 6-10 mg/kg IM, IV q24h

Penicillin, benzathine , benzathine

• May be administered concurrently with amikacin
• 10,000 units/kg IM q48-96h

Penicillin G

• Infrequently used
• 10,000-20,000 units/kg IM, SC, IV, ICo q8-12h

Piperacillin

• Administer fluids concurrently
• May be used with an aminoglycoside
• 50-100 mg/kg IM q24h
• 100-200 mg/kg IM q24-48h in chameleons
• 100 mg/10ml saline x 30 min nebulisation q12h

Streptomycin

• Potentially nephrotoxic
• Administer fluids concurrently
• Avoid with renal/hepatic dysfunction
• 10 mg/kg IM q12-24h

Sulphadiazine

• Administer fluids concurrently
• Do not use with renal impaired animals
• 25 mg/kg PO q24h

Sulphadimethoxine

• Potentially nephrotoxic
• Administer fluids concurrently
• 90 mg/kg IM then 45 mg/kg q24h

Tetracycline

• May disturb the normal intestinal microflora
• 10 mg/kg PO q24h

Ticarcillin

• Administer fluids concurrently
• 50-100 mg/kg IM q24h

Tobramycin

• Potentially nephrotoxic
• Administer fluids concurrently
• Potentiated by â-lactams
• 2 mg/kg IM q24h
• 2.5 mg/kg IM q12h in chameleons

Trimethoprim/sulphadiazine

• Administer fluids concurrently
• 15 mg/kg IM q24

Trimethoprim/sulphamethoxaline

• Administer fluids concurrently
• 10-30 mg/kg PO q24h

Tylosin

• Reported useful for mycoplasma respiratory infections
• 5 mg/kg IM q24 10-60d