Intramuscular administration of two dosage forms of benzylpenicillin in horse - pain assessment
In veterinary medicine, penicillin is the most used antibiotic in Sweden. Two dosage forms of penicillin are available in Sweden for use in horses, sodium benzylpenicillin (Na-pc) and procaine benzylpenicillin (proc-pc). Proc-pc is the most used dosage form and is used for intramuscular administrati...
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| Formato: | H2 |
| Lenguaje: | Inglés sueco |
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SLU/Dept. of Biomedical Sciences and Veterinary Public Health (until 231231)
2010
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| Sumario: | In veterinary medicine, penicillin is the most used antibiotic in Sweden. Two dosage forms of penicillin are available in Sweden for use in horses, sodium benzylpenicillin (Na-pc) and procaine benzylpenicillin (proc-pc). Proc-pc is the most used dosage form and is used for intramuscular administration which allows horse owners to treat an animal at home under veterinary instruction. Na-pc is only approved for intravenous use in horses.
Penicillin is normally well tolerated by horses but a serious, sometimes life-threatening, adverse reaction called penicillin shock may occur. Most cases of penicillin shock are believed to be caused by procaine toxicity and the number of adverse reactions could possibly be reduced if proc-pc is replaced by another drug. At the moment, there is no good alternative to proc-pc available. The aim of the study is to see if Na-pc is an alternative to proc-pc for intramuscular administration in horses and to assess pain associated with injection. The study was a randomized, blinded, cross-over study in eight healthy horses. The horses were injected intramuscularly with proc-pc once a day four times and Na-pc twice a day seven times in total.
Behavioural studies and clinical evaluation were performed to see if there are any differences in pain associated with injection of Na-pc and proc-pc. The horses were studied for four minutes before and four minutes after the morning injection. The clinical evaluation was performed 24 hours after the last injection. The pain assessment presented in this paper is part of a larger study.
The study shows that after injection with Na-pc horses are more likely to walk and stretch their necks and less likely to rest their necks than after injection of proc-pc. They will also shake their necks more and kick/stamp/scrape with their front legs more. Before injections of Na-pc horses are less likely to rest their necks than before injection of proc-pc, however this difference could not be seen before the first injection. This suggests that the horses might be in pain 12 hours after the previous injection. The clinical examination showed that after repeated injections of Na-pc horses were more swollen at the injection site and had stronger pain reaction than after repeated injections of proc-pc.
The conclusions of the study are that injections of Na-pc causes more pain than proc-pc when administered intramuscularly and that the degree of pain cannot be accepted because of animal welfare concerns. The reason why Na-pc causes more pain could be because of the absence of procaine, which is a local anaesthetic. Another contributing factor to Na-pc causing more pain could be that it was administered twice a day which could result in more muscle soreness than injection once a day. Na-pc cannot be recommended for intramuscular use in horses and the need to find a replacement to proc-pc still remains.
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