Anti-bacterial drugs (“Antibiotics”)
Principles of anti-bacterial drug therapy:
- Anti-bacterial drugs (or “antibiotics”) are usually given as a course of injections or oral medication over a period of at least 3-5 days, with treatment continued for long enough to cure infection & prevent relapse. Clearly, this will only be possible in captive situations.
- Ideally a bacterial pathogen is identified and the appropriate antibiotic selected according to bacterial culture and sensitivity testing in a diagnostic laboratory, plus consideration of local factors such as drug penetration into bone, effectiveness in the presence of pus, etc. This is not practical if a tiger is to be treated in the field and released on the same day.
- A good response will usually be seen within 24-48hrs of beginning a course of antibiotics. If there has been no favourable response, a change in drug or dose rate may be necessary.
- Serious infections, particularly where bone is involved, may require a course of therapy over months, and would necessitate keeping a patient in temporary captivity.
- When injecting antibiotics a sterile new needle and syringe should be used for each dose. It is good practice to swab the top of the drug bottle prior to insertion of the needle to reduce the risk of contamination.
- It is also good practice to swab the skin of the animal before injecting and ensure that injections are not given in a region of skin soiled with excess faeces or dirt.
- Use of antibiotics to prevent or treat wound infections is not a substitute for good wound cleaning.
- Anti-bacterial drugs will be inactivated or reduced in efficacy by prolonged exposure to light or high temperatures. Refrigerated storage is advised.
Field use:
- Long-acting antibiotic preparations are particularly useful for field use when the patient will not be taken into captivity for treatment. These provide a course of anti-bacterial drug lasting between 3 and 14 days following a single injection.
- Use of antibiotics to prevent or treat wound infections is not a substitute for good wound cleaning.
- Prophylactic long-acting antibiotic injections are recommended to all animals that have experienced trauma, snaring and anaesthesia.in the field.
- Anti-bacterial drugs will be inactivated or reduced in efficacy by prolonged exposure to light or high temperatures. Refrigerated storage is advised.
| Anti-bacterial drug | Dose rate | Comments | Refs |
|---|---|---|---|
| Amoxicillin | 15mg/kg PO, IM, SC, q12hrs | Bacteriocidal. | |
| Amoxicillin Long-acting | 15mg/kg IM q3days | Long-acting preparation (2-3 days) of amoxicillin trihydrate, 150mg/ml. Dose rate is equivalent to 1ml per 10kgs. | |
| Amoxicillin/clavulanic acid | 12.5 - 25mg/kg PO, IM, IV, SC, q12hrs | Bacteriocidal. First line antibiotic of choice. | |
| Ampicillin | 22mg/kg PO, IM, IV, SC | Limited reports of use. | 2, 3 |
| Azithromycin | 7-15mg/kg PO, q12hrs | For Cryptosporidial infections, give for 5-7 days. | 1 |
| Cephalexin | 12.5-25mg/kg PO, q12hrs | Doses < 35mg/kg q8hrs have been used. | 3 |
| Cefovexin | 4mg/kg SC, IM, q2 weeks. Or 8mg/kg SC, IM, once only. | Long-acting cephalosporin (at least 14 days). Useful for animals that won't tolerate oral medication. At 4mg/kg max 3 doses 14 days apart. | 1, 5 |
| Cefazolin | 22mg/kg IV, SC | Limited reports of use. | 2, 3 |
| Clarithromycin | 5-10mg/kg PO, q24hrs | ||
| Clindamycin | 5.5mg/kg PO, q12hrs or 11mg/kg PO, q24hrs | Good bone penetration. Can be used against toxoplasmosis at higher doses. | |
| Doxycycline | 10mg/kg PO, q24hrs | Broad spectrum antibiotic. Antibiotic of choice for haemobartonellosis & chlamydophylosis. Give 4 week course for chlamydophilosis. | |
| Enrofloxacin | 5mg/kg PO, IM, SC, q24hrs | Broad spectrum antibiotic. Used in tigers without retinal side-effects. | 2, 4 |
| Marbofloxacin | 2mg/kg PO, IM, SC, q24hrs | Broad spectrum antibiotic | |
| Metronidazole | 7.5-10mg/kg PO, q12hrs or 15-20mg/kg PO, q24hrs | Used v's anaerobic bacterial infections. For use v's Giardia - see "Anti-parasite drugs" | |
| Oxytetracycline | 10mg/kg IM, SC, q24hrs. | Bacteriostatic. Oral route not recommended due to poor absorption. | |
| Oxytetracycline long-acting formulations 300mg/ml | 20mg/kg deep IM, q72hrs. | Lasts 3-4 days following a single injection at 20mg/kg. Deep IM injection only. | |
| Oxytetracycline long-acting formulations 300mg/ml | 30mg/kg deep IM, q5 days | Lasts 5-6 days following a single injection at 30mg/kg. Deep IM injection only. | |
| Trimethoprim-sulfamethoxazole | 30mg/kg PO, q12hrs | 3 |
References:
1Cushing et al, 2017. Pharmacokinetic parameters of cefovecin sodium (Convenia) in captive tigers (Panthera tigris).
Journal of Zoo & Wildlife Medicine, 48(4): 1188-1192.
2McCain et al, 2009. Pyometra in captive large cats: A review of eleven cases. Journal of Zoo & Wildlife Medicine, 40(1): 147-151.
3Hahn, 2019. Zoo and wild mammal formulary.
4Newkirk et al, 2017. Investigation of enrofloxacin-associated retinal toxicity in nondomestic felids. Journal of Zoo & Wildlife Medicine, 48(2): 518-520
5BSAVA formulary
