Classification and Dosage of Antimicrobial Agents in Veterinary Medicine
Classification and Dosage of Antimicrobial Agents in Veterinary Medicine
Classification and Dosage of Antimicrobial Agents in Veterinary Medicine
Antibiotics asre the substances prioducd by the microorganisms which suppress rthe
growth/ kill the microorganism at a low concentration without affecting/ causing much damage
to the host. These exclude the other substances which also inhibit/ kill the microorganisms, but
are produced synthetically( eg: sulphonamides) or those substances needing higher
concentration to inhibit, though produced by the microbes (eg; ethanol). Since many
antibiotics and their analogues have been synthesized both synthetically and microbially, these
agents are together termed as antimicrobial agents (AMA) . Since antimicrobial agents belong
to diverse chemical class, they can be classified based on their chemistry, mechanism of
action. spectrum of activity, source from which they are obtained etc
2. CEPHALOSPORINS
a. First generation-cefacetrile, cephalexin, cefalothin, cefaridine,
cefatrizine,cefazolin,cefalonium,cefadroxil,cefapirin,
cefradine and cephaloglycin
b. Second generation- cefaclor, cefamandole,cefmetazole, ceforanide,
cefonicid, cefacetrile, cefmenoxime, cefotiam
cefotetan, cefprozil, and cefuroxime.
c. Third generation - cefixime, cefoperazone,cefotaxime, cefpodoxime,
ceftazidime, ceftizoxime, ceftiofur ceftriaxone,
cefdinir,ceftibuten,cefsulodin,latamoxef(moxalactam)and
cefodizime
d. Fourthgeneration-cefquinome,cefepime,cefpirome,cefmetazole,cefditoren
3. CARBAPENEMS- imipenem, meropenem, faropenem
4. MONOBACTAMS-aztreonam
5. AMINOGLYCOSIDES a. Aminocyclitol- spectinomycin
b. Aminoglycosides- streptomycin, dihydrostreptomycin
framycetin, kanamycin, neomycin, paromomycin, apramycin,
gentamicin, , amikacin, sisomycin, netilmicin and tobramycin
6. PHENICOLS- florphenicol, thiamphenicol, chloramphenicol
7. SULFONAMIDES- Sulfachlorpyridazine,sulfadiazine,Sulfadimerazine,Sulfadimethoxine
Sulfadimidine,Sulfadoxine,Sulfafurazole,Sulfaguanidine,Sulfamethazine,
sulfadimethoxazole,Sulfamethoxine,Sulfamonomethoxine,Sulfanilamide,
Sulfaquinoxaline.Sulfonamides+Diaminopyrimidines-
sulfamethoxypyridazine,Trimethoprim+Sulfonamide.Diaminopyrimidines-
Baquiloprim,Trimethoprim
8. STREPTOGRAMINS-virginiamycin, quinupristin ,dalfopristin
9. TETRACYCLINES-chlortetracycline,doxycycline,oxytetracycline,tetracycline,
Demeclocycline, methacycline, lymecycline, minocycline
CHLORAMPHENICOL
Species Dosage form Route Dose Interval Comment
(mg/kg) (hr)
TETRACYCLINES
Long acting IM 20 48
tetracycline (2PVP)
ANTI-NEOPLASTIC DRUGS
DRUGS MECHANISM OF MAJOR Dose& Route of
ACTION INDICATIONS Adm.
ALKYLATING
AGENTS alkylate DNA, Lymphoma, sarcomas, 60mg/kgBW
Cyclophosphamide cross-linking of mammary daily oral
DNA strands adenocarcinoma,
lymphocytic leukemia
Melphalan Alkylates DNA Multiple myeloma 150mcg/kgBW
causing miscoding daily or
and cross-linking of 250mcg/kgBW
DNA strands daily for 4
weeks oral
Chlorambucil Alkylates DNA Chronic lymphocytic 100mcg/kgBW
causing miscoding leukemia, lymphoma daily oral
DNA strands
Carboplastin Inhibits both DNA CNS neoplasias ,GI 300-360mg/m2
and RNA synthesis carcinomas, multiple BSA by IV
myeloma
Streptozocin Inhibits DNA Temporary remission of 100mcg/kgBW
synthesis hypoglycemia resulting daily
from functional
pancreatic islet cell
tumor
Dacarbazine alkylate DNA, Lymphoma 2-4.5mg/kgBW
inhibits RNA daily for 10
synthesis days IV10-
15mg/day for 4-
8days oral
Busulfan Alkylates DNA, Chronic myelogenous 60mcg/kg BW
causing miscoding of leukemia, polycythemia daily oral
DNA strands vera
ANTIMETABOLITES
Methotrexate Inhibits formation of Lymphoma, Sertoli cell 10-15mg/day
tetrahydrofolate, a tumor, osteosarcoma, for 4-8 days oral
necessary cofactor in metastatic transmissible
thymidylate venereal tumor
synthesis, essential
for DNA synthesis
and repair
Fluorouracil Pyrimidine analog, GI, lung, liver, and 15mg/kgBW
interferes with DNA mammary carcinomas once a week
synthesis and may be (systemic); cutaneous oral
incorporated into carcinomas (topical) 15mg/kgBW in
RNA to cause toxic 500ml DNS
effects
Cytarabine Pyrimidine analog, Lymphoma (including 100mg/m2 BSA
incorporates into CNS), leukemias bid by rapid
DNA causing stereo inj.IV.& Ithecal
hindrance and 10-30mg/m2for
inhibition of DNA meningitis
synthesis
ANTIBIOTICS
Dactinomycin disrupting helical Choriocarcinoma, 15mcg/kgBW
(Actinomycin D) structure and DNA testicular carcinoma, per day or400-
template, inhibits rhabdomyosarcoma, 600 mcg/m2
RNA and DNA lymphoma BSA IV
polymerases
Doxorubicin Disrupts helical Lymphoma, acute 60-75mg/ m2
structure and DNA lymphocytic and BSA IV
template, inhibits granulocyticleukemia,
RNA and DNA sarcomas carcinomas,
polymerases
Mitoxantrone DNA aggregation, Lymphoma,carcinomas, 8-12mg/ m2
oxidation, and strand fibrosarcoma, BSA IV
breakage hemangiopericytoma
Bleomycin generates oxygen Carcinomas (testicular, 15,000IU thrice
radicals that cause squamous cell of head a week IM/IV
chain scission and and neck, cervical,
fragmentation of penile)lymphoma,
DNA seminoma,malignant
teratoma
MITOTIC disruption of mitotic Lymphoma and 0.1-
INHIBITORS spindle apparatus leukemias, 0.5mg/kgBW
Vinblastine and arrest of cell mastocytoma IV
cycle
Vincristine disruption of mitotic Transmissible venereal 25-75 mcg/kg or
spindle apparatus cell tumors, lymphoma 1.4mg/m2
and arrest of cell and leukemias, CNS IV
cycle tumors, mammary
adenocarcinoma, soft-
tissue sarcomas,
immune-mediated
thrombocytopenia
HORMONES
Prednisolone inhibits mitosis in Lymphoma, mast cell 60mg/m2 IM,IV
lymphocytes tumors, palliative
treatment of brain
tumors
Tamoxifen Anti-estrogenic; Estrogen-receptor- 20mg/day single
blocks the effects of positive mammary dose oral
estrogen on target carcinomas
tissues
Flutamide Anti-androgenic; Testosterone-receptor- 250mg TID oral
competes with positive prostatic
testosterone for tumors; surgical
binding to androgen castration preferred
receptors
Leuprolide GnRH analog that Testosterone-receptor 1-3.5mg IM or
initially stimulates, positive prostatic SC
then decreases, the carcinomas or perianal
secretion of FSH and tumors, surgical
LH,lead to decreased castration preferred
concentrationof
testosterone (males)
and estrogen
(females)
APPENDIX
The relation of body weight to surface area in square meters
for dogs is given in the following table:
Kg m2 Kg m2 Kg m2
0.5 0.06 17 0.66 34 1.05
1 0.10 18 0.69 35 1.07
2 0.15 19 0.71 36 1.09
3 0.20 20 0.74 37 1.11
4 0.25 21 0.76 38 1.13
5 0.29 22 0.78 39 1.15
6 0.33 23 0.81 40 1.17
7 0.36 24 0.83 41 1.19
8 0.40 25 0.85 42 1.21
9 0.43 26 0.88 43 1.23
10 0.46 27 0.90 44 1.25
11 0.49 28 0.92 45 1.26
12 0.52 29 0.94 46 1.28
13 0.55 30 0.96 47 1.30
14 0.58 31 0.99 48 1.32
15 0.60 32 1.01 49 1.34
16 0.63 33 1.03 50 1.36
Body surface area in square meters for dogs and cats may be obtained from the
following formula:
K x W2/3
BSA = ----------------
104
Where, K = constant (10.1 for dogs ; 10 for cats)
W = weight in grams
BSA = Body surface area in square meters
Doses for anticancer drugs are calculated as a function of body surface areas (m) rather than
body weight because the blood supply to the organs responsible for detoxification, kidney and
liver, is more closely related to surface area than body weight
Inhibit glycolysis