PMID- 3437496
OWN - NLM
STAT- MEDLINE
DCOM- 19880404
LR  - 20190919
IS  - 0140-7783 (Print)
IS  - 0140-7783 (Linking)
VI  - 10
IP  - 4
DP  - 1987 Dec
TI  - The effect of age and diet on sulfadiazine/trimethoprim disposition following 
      oral and subcutaneous administration to calves.
PG  - 331-45
AB  - Thirty milligrams per kilogram of sulfadiazine/trimethoprim (SDZ/TMP, Tribrissen) 
      was given orally and subcutaneously (s.c.) to two groups of male, Holstein 
      calves. One group was fed milk-replacer throughout the 13-week period of the 
      study while the second group was weaned onto a chopped grain-fiber mixture when 5 
      weeks old. Serum and urine were assayed for concentrations of unchanged drug. 
      Trimethoprim bioavailability, following oral administration at 1, 6 and 12 weeks 
      of age, is higher in milk-fed calves (non-ruminants) than in grain-fiber-fed 
      calves (ruminants); bioavailability decreases with increasing age in both groups 
      of calves. Serum concentrations above 0.1 micrograms/ml (the level of sensitivity 
      of the assay) could not be obtained in ruminating calves. The rate of SDZ 
      absorption following oral administration, as determined by the Wagner-Nelson 
      method, was very slow in all the calves in this study with average half-life 
      values ranging from 8.2-12.67 h; absorption was slightly faster in ruminating 
      calves. Absorption of SDZ is rate-limiting and determines the biological 
      half-life of the drug; SDZ serum concentrations above 2 micrograms/ml were 
      maintained in all calves for at least 24 h. Following s.c. administration of 
      Tribrissen to 7-and 13-week-old calves, urinary excretion patterns indicated that 
      TMP was slowly released from the injection site; serum concentrations were below 
      0.1 micrograms/ml. In contrast, absorption of SDZ was very rapid; values for tmax 
      were 1.5-1.8 h. The pharmacokinetic parameters for SDZ were calculated according 
      to a one-compartment open model; neither diet nor age had a significant effect on 
      SDZ disposition following s.c. injection. Subcutaneous administration of 30 mg/kg 
      Tribrissen, b.i.d., may be the best therapeutic regimen; even though measureable 
      concentrations of TMP cannot be achieved in the serum following a single s.c. 
      dose, TMP concentrations should accumulate and, because of its sustained release, 
      provide almost continual potentiation of SDZ.
FAU - Shoaf, S E
AU  - Shoaf SE
AD  - Department of Pharmacology, New York State College of Veterinary Medicine, 
      Cornell University, Ithaca 14853.
FAU - Schwark, W S
AU  - Schwark WS
FAU - Guard, C L
AU  - Guard CL
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - England
TA  - J Vet Pharmacol Ther
JT  - Journal of veterinary pharmacology and therapeutics
JID - 7910920
RN  - 0 (Drug Combinations)
RN  - 0N7609K889 (Sulfadiazine)
RN  - 39474-58-3 (sulfadiazine, trimethoprim drug combination)
RN  - AN164J8Y0X (Trimethoprim)
SB  - IM
MH  - Absorption
MH  - Administration, Oral
MH  - Age Factors
MH  - Animals
MH  - Biological Availability
MH  - Cattle/*metabolism
MH  - Diet
MH  - Drug Combinations/administration & dosage/metabolism
MH  - Drug Synergism
MH  - Half-Life
MH  - Injections, Subcutaneous/veterinary
MH  - Male
MH  - Sulfadiazine/administration & dosage/*metabolism/*pharmacokinetics
MH  - Trimethoprim/administration & dosage/*metabolism/*pharmacokinetics
EDAT- 1987/12/01 00:00
MHDA- 1987/12/01 00:01
CRDT- 1987/12/01 00:00
PHST- 1987/12/01 00:00 [pubmed]
PHST- 1987/12/01 00:01 [medline]
PHST- 1987/12/01 00:00 [entrez]
AID - 10.1111/j.1365-2885.1987.tb00110.x [doi]
PST - ppublish
SO  - J Vet Pharmacol Ther. 1987 Dec;10(4):331-45. doi: 
      10.1111/j.1365-2885.1987.tb00110.x.