Abstract
Objective - To determine pharmacokinetics of azathioprine (AZA) and clinical, hematologic, and serologic effects of IV and oral administration of AZA in horses. Animals - 6 horses. Procedure - In study phase 1, a single dose of AZA was administered IV (1.5 mg/kg) or orally (3.0 mg/kg) to 6 horses, with at least 1 week between treatments. Blood samples were collected for AZA and 6-mercaptopurine (6-MP) analysis 1 hour before and at predetermined time points up to 4 hours after AZA administration. In study phase 2, AZA was administered orally (3 mg/kg) every 24 hours for 30 days and then every 48 hours for 30 days. Throughout study phase 2, blood samples were collected for CBC determination and serum biochemical analysis. Results - Plasma concentrations of AZA and its metabolite, 6-MP decreased rapidly from plasma following IV administration of AZA, consistent with the short mean elimination half-life of 1.8 minutes. Oral bioavailability of AZA was low, ranging from 1% to 7%. No horses had abnormalities on CBC determination or serum biochemical analysis, other than 1 horse that was lymphopenic on day 5 and 26 of daily treatment. This horse developed facial alopecia from which 1 colony of a Trichophyton sp was cultured; alopecia resolved within 1 month after the study ended. Conclusions and clinical relevance - Overall, no adverse effects were observed with long-term oral administration of AZA to horses, although 1 horse did have possible evidence of immunosuppression with chronic treatment. Further investigation of the clinical efficacy of AZA in the treatment of autoimmune diseases in horses is warranted.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1578-1583 |
| Number of pages | 6 |
| Journal | American Journal of Veterinary Research |
| Volume | 66 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 2005 |
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- veterinary(all)
Cite this
Pharmacokinetics of azathioprine following single-dose intravenous and oral administration and effects of azathioprine following chronic oral administration in horses. / White, Stephen D; Maxwell, Laura K.; Szabo, Nancy J.; Hawkins, Jocelyn L.; Kollias-Baker, Cynthia.
In: American Journal of Veterinary Research, Vol. 66, No. 9, 09.2005, p. 1578-1583.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pharmacokinetics of azathioprine following single-dose intravenous and oral administration and effects of azathioprine following chronic oral administration in horses
AU - White, Stephen D
AU - Maxwell, Laura K.
AU - Szabo, Nancy J.
AU - Hawkins, Jocelyn L.
AU - Kollias-Baker, Cynthia
PY - 2005/9
Y1 - 2005/9
N2 - Objective - To determine pharmacokinetics of azathioprine (AZA) and clinical, hematologic, and serologic effects of IV and oral administration of AZA in horses. Animals - 6 horses. Procedure - In study phase 1, a single dose of AZA was administered IV (1.5 mg/kg) or orally (3.0 mg/kg) to 6 horses, with at least 1 week between treatments. Blood samples were collected for AZA and 6-mercaptopurine (6-MP) analysis 1 hour before and at predetermined time points up to 4 hours after AZA administration. In study phase 2, AZA was administered orally (3 mg/kg) every 24 hours for 30 days and then every 48 hours for 30 days. Throughout study phase 2, blood samples were collected for CBC determination and serum biochemical analysis. Results - Plasma concentrations of AZA and its metabolite, 6-MP decreased rapidly from plasma following IV administration of AZA, consistent with the short mean elimination half-life of 1.8 minutes. Oral bioavailability of AZA was low, ranging from 1% to 7%. No horses had abnormalities on CBC determination or serum biochemical analysis, other than 1 horse that was lymphopenic on day 5 and 26 of daily treatment. This horse developed facial alopecia from which 1 colony of a Trichophyton sp was cultured; alopecia resolved within 1 month after the study ended. Conclusions and clinical relevance - Overall, no adverse effects were observed with long-term oral administration of AZA to horses, although 1 horse did have possible evidence of immunosuppression with chronic treatment. Further investigation of the clinical efficacy of AZA in the treatment of autoimmune diseases in horses is warranted.
AB - Objective - To determine pharmacokinetics of azathioprine (AZA) and clinical, hematologic, and serologic effects of IV and oral administration of AZA in horses. Animals - 6 horses. Procedure - In study phase 1, a single dose of AZA was administered IV (1.5 mg/kg) or orally (3.0 mg/kg) to 6 horses, with at least 1 week between treatments. Blood samples were collected for AZA and 6-mercaptopurine (6-MP) analysis 1 hour before and at predetermined time points up to 4 hours after AZA administration. In study phase 2, AZA was administered orally (3 mg/kg) every 24 hours for 30 days and then every 48 hours for 30 days. Throughout study phase 2, blood samples were collected for CBC determination and serum biochemical analysis. Results - Plasma concentrations of AZA and its metabolite, 6-MP decreased rapidly from plasma following IV administration of AZA, consistent with the short mean elimination half-life of 1.8 minutes. Oral bioavailability of AZA was low, ranging from 1% to 7%. No horses had abnormalities on CBC determination or serum biochemical analysis, other than 1 horse that was lymphopenic on day 5 and 26 of daily treatment. This horse developed facial alopecia from which 1 colony of a Trichophyton sp was cultured; alopecia resolved within 1 month after the study ended. Conclusions and clinical relevance - Overall, no adverse effects were observed with long-term oral administration of AZA to horses, although 1 horse did have possible evidence of immunosuppression with chronic treatment. Further investigation of the clinical efficacy of AZA in the treatment of autoimmune diseases in horses is warranted.
UR - http://www.scopus.com/inward/record.url?scp=27744481152&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=27744481152&partnerID=8YFLogxK
U2 - 10.2460/ajvr.2005.66.1578
DO - 10.2460/ajvr.2005.66.1578
M3 - Article
C2 - 16261832
AN - SCOPUS:27744481152
VL - 66
SP - 1578
EP - 1583
JO - American Journal of Veterinary Research
JF - American Journal of Veterinary Research
SN - 0002-9645
IS - 9
ER -