Pharmacotherapy in reptiles univ. prof. Zdenek Knotek, DVM, PhD University of Veterinary and Pharmaceutical Sciences Brno Czech Republic
Pharmacokinetism - temperature Reptiles are ectotherm vertebrates. Their metabolism is dependent (influenced with) on external temperature. In nature – reptiles try to keep the body in preferred body temperature (PBT) optimal condition for metabolic pathways. Patients keep their PBT - spending maximum time in special part of the terraria - behavioral thermoregulation.
Pharmacokinetism - temperature Reptiles are ectotherm vertebrates. Preferred optimum temperature zone (POTZ) is condition for PBT. • Keep your patients in POTZ – during treatment, anaesthesia, surgery, recovery period. • Lower (suboptimal) temperatures – prolong the recovery time. • Lower (suboptimal) temperatures – increase the risk of overdose drugs (aminoglycosides).
Special anatomy/physiology of reptiles Quadriped reptiles - renal portal system. Presence/absence – urinary bladder – ventral extension of urodeum. Central organ for final urine production.
Special anatomy/physiology of reptiles • The most of snake species have only the right lung. Do not insert the endotracheal tube into left lung rudiment. • Reptiles have very low respiratory frequence. It is lowest within anaesthesia. • Reptiles can tolerate very low oxygen concentration in peripheral blood (organs, tissues). • Semia-quatic/aquatic reptiles – shunt of blood circulation within the period of submergence.
Special anatomy/physiology of reptiles GIT – in carnivorous reptiles (crocodiles, aquatic terapins, snakes and some lizards) short distance. Transit time for contrast fluids (X-ray), food, drug metabolites is short (days). GIT – in herbivorous reptiles (land tortoises, lizards) long. Transit time for contrast fluids (X-ray), food, drug metabolites is long, very slow passage (weeks).
DIAGNOSIS and TREATMENT §1
Think before treat !
§2
Disease is complex !
§3
Concurrent diseases !
§4
Patient is complex !
§5
Topical and/or systemic treatment !
§6
Follow the recommendations !
§7
Reptiles- crocodiles, chelonians, snakes, lizards
DIAGNOSIS and TREATMENT EMERGENCY ?
Reptiles are generally presented injured or ill. Good history - valuable lead to the problem. In many cases - only an illusion. Prepare your own questionare protocol origin of the reptile housing system feeding regimen temperature, air humidity, water, substrate, UVB any previous treatment? previous reproductive activity?
The success of treating a critical patient relies very heavily on the environment in which the animal must recover. When possible make visually-separated housing for each of the reptile patients. They may experience unnecessary extra stress in a living with visual contact with other reptiles (predators).
Basic equipment to practice with reptiles a gram scale a lightweight plastic transport containers endoscope (2.7 mm or less) X–ray microscope with oil immersion capability quick-staining kit for smears and cytology, centrifuge, haemocytometer biochemistry testing system.
Side effects Aminoglycosides amikacin, gentamycin, kanamycin, netilmycin, tobramycin
+ G- bacterial infections glomerular filtration
-
nephrotoxic (neurotoxic, ototoxic, cardiotox) efects
Side effects Tetracyclin ATBs doxycyclin, chlortetracyclin, oxytetracyclin, tetracyclin
+ G+ i G- infections, low nephrotoxic
-
teratogenic (pregnanc), nauzea, vomitus, hepatotoxicefekt (liver steatosis), bacteriostatic
Side effects Quinolon enrofloxacin, ciprofloxacin + G+ a G- infekcí, suspect teratogenic (pregnancy), negative influence on bones (growth, joints)
Metronidazole + (Clostridia, Entamoeba, Hexamita) - neurotoxic efect of reccommended doses (heavy reptiles)
Ivermectin + (endoparasites, ectoparasites) - toxic for tortoises, turtles
Administartion Per os + GIT Per cloacam
Parenteral SC, IM, IPP, IV, IO
Metabolic (Allometric) scalling BMR (kcal) = K.H0.75 • birds - passerine birds • birds - non-passerine birds • mammals • reptiles
(K = 129) (K = 78) (K = 70) (K = 10)
Antimicrobial Agent Acyclovir
Dosage 80 mg/kg PO q24h x10
agents ATB Comments Tortoises (herpes)
Topical (5% ointment) q12h Tortoises (herpes) Ampicilin Amikacin
20 mg/kg IM q24h x 7
Tortoises
2.5 mg/kg IM, SC q72h x 7
Nephrotoxic agent
Gentamycin 1.75 - 2.5 mg/kg IM q72 h x7 Nephrotoxic agent Kanamycin
5 - 15 mg/kg q24 - 48 x 5 - 7 Nephrotoxic agent
Antimicrobial agents ATB Agent
Dosage
Comments
Chloramphenicol
20 - 50 mg/kg PO
q24h x 7
Streptomycin
6 - 10 mg/kg IM
q24h x 5 - 7
Tetracycline Tylosine Cindamycin Doxycycline
25 - 50 mg/kg IM, PO
q24h x 6
5 - 10 mg/kg IM
q24h x10 crocodiles
2.5 - 5 mg/kg PO
q12-24h x 7
50(1)+25(3 - 6)mg/kg IM q48 - 72h x 6
Antimicrobial agents ATB Agent Cefotaxime Ceftazidime
Dosage
Comments
20 - 40 mg/kg IM
q24h x 7 - 14
20 mg/kg IM
q72h x 14 - 21
Cephalexin
20 - 40 mg/kg IM
q12h x 7
Cephalothin
20 - 40 mg/kg IM
q48h x 7 chelonians
Cephazolin
20 - 40 mg/kg IM
q24h x 7 - 14
Cephoperazone
125 mg/kg IM
q24h x 7 lizards
Antimicrobial agents ATB Agent Enrofloxacin Ciprofloxacin
Dosage 10(15) mg/kg SC, PO
Comments q24h x 7 - 21
10 mg/kg PO
q48h x 3 - 5
20 - 50 mg/kg PO
q24h x 3 - 5
Trimethoprim / sulfamethoxazole
30(1)+15 mg/kg
q24h x 10 - 14
Sulphadimidine
50 mg/kg PO
q24h x 10
Sulphamerazine
25 mg/kg PO
q24h x 7
Metronidazole
Antifungal agents Agent
Dosage
antimycotics Comments
Amphotericin B
0.5 - 1 mg/kg PO, IPP q24 - 48h x 28
Griseofulvin
20 - 40 mg/kg PO
q72h x 5
topical
ointment
Clotrimazole Fluconazole Itraconazole Ketoconazole
5 mg/kg PO
q24h x 28
24 mg/kg PO
q24h x 28
15 - 30 mg/kg PO
q24h x 28
Antifungal agents Agent
antimycotics
Dosage
Comments
Chlorhexidine
20 ml/gal water bath
Lizards - dermatoph.
Malachite green
0.15 mg/l water x 1 hr
q24h x 14
Miconazole Nystatin Tolnaftate 1% cream
topical 100 000 i.u./kg PO topical
ointment q24h x 10 q12h
Antiparasitic agents Parasites
Amoeba
Flagellata
Agent
Dosage
Metronidazole
20 – 40 (100) mg/kg 3x
Dimetridazole
40 mg/kg q24h x 4
Paromomycin
35 – 60 mg/kg after week
Metronidazole
20 – 40 (100) mg/kg 3x
Dimetridazole
40 mg/kg q24h x 4
Ronidazole
10 mg/kg q24h x 10
Antiparasitic Parasites
Coccidia
Agent
agents Dosage
Toltrazuril
10 mg/kg q72h x 5
Sulfadimethoxine Sulfamethoxydiazine
75 – 90 mg/kg I.day 40 – 45 mg/kg II. – IV. 40 – 60 mg/kg q24h x 4
Sulfadiazine
20 – 50 mg/kg q24h x 3
Cryptosporidium Trimethoprim / sulfa Spiramycin
30 – 60 mg/kg q24h x 7 160 mg/kg q24h x 10
Antiparasitic agents Parasites
Agent Ivermectin
Trematoda Praziquantel
Ivermectin
Cestoda
Dosage 0.2 mg/kg SC Chelonians 10 – 30 mg/kg q14 days
Praziquantel
0.2 mg/kg SC Chelonians 10 – 30 mg/kg q14 days
Niclosamid
150 mg/kg q14 days
Antiparasitic agents Parasites
Agent
Dosage
Fenbendazole
10 – 30 mg/kg q 14 days
Pyrantel pamoate
5 mg/kg q 14 days
Nematoda Ivermectin Piperazine
0.2 mg/kg SC Chelonians 40 – 60 mg/kg q 14 days
Albendazole
50 mg/kg q 14 days
Mebendazole
20 – 100 mg/kg q 14 days
Hormones + steroids Agent
Dosage
Arginine vasotocin
0.5 - 1.0 μg/kg IV,IPP
Oxytocin
1 - 10 i.u./kg IM
Calcitonin
1.5 i.u./kg SC
Dexamethasone
2 - 4 mg/kg IM
q24h x 3
Prednisolone
2 - 5 mg/kg IM, PO
chronic pain
Nandrolone
1 mg/kg IM
Comments q12 - 24h after 2x calcium inj. q8h x 2 - 3
anabolic, PHA
Nutritional Agent Ca - gluconate borogluconate
Ca - gluconate Iodine Iron dextran Lactated Ringer ´s solution
/ mineral / fluid support Dosage 10 - 50mg/kg IM 100mg/kg IPP, SC 2 - 4 mg/kg PO 12 mg/kg IM 10 - 25 ml/kg SC, IPP
Comments hypocalcemia q8h MBD, seizures q24h x 2 - 3w 1 - 2 x w, crocodiles q24h
Nutritional Agent Vitamin A Vitamin B complex
/ mineral / fluid support Dosage
Comments
1000 - 5000 i.u./kg IM
q7-14d x 4
25 mg thiamine/kg PO
q24h x 3-7 days
Vitamin C
10 - 20 mg/kg SC, IM
q24h
Vitamin D3
200 i.u./kg IM, PO
q7days
Vitamin E Vitamin K1
1 i.u./kg IM 25 mg/kg IM
1000 - 5000 i.u./kg IM
hypovitaminosis coagulopaties
Miscellaneous Agent
Dosage
agents Comments
Allopurinol
10 - 20 mg/kg PO
q24h
Sucralfate
500 - 1000 mg/kg PO
q6 - 8h
Cimetidine
4 mg/kg PO, IM
q8 - 12h
Cisapride
0.5 - 2.0 mg/kg PO
Furosemide
5 mg/kg PO, IM
Metoclopramide
0.06 - 5 mg/kg PO
q24h q12 - 24h q24h x 7
Miscellaneous Agent Lactulose Liquid paraffin Dioctyl Na sulfosuccinate Barium sulfate
Dosage 0.5 ml/kg PO 25 (1:1 electr)/kg PO
agents Comments q24h q24h, constipation
1 - 5 mg/kg PO
constipation
5 - 20 ml/kg PO
GIT contrast