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Home / Equine Research Bank / Vet Res Commun / Comparative pharmacokinetics of diphenhydramine in camels an...
Veterinary research communications2003; 27(6); 463-473; doi: 10.1023/a:1025789607863

Comparative pharmacokinetics of diphenhydramine in camels and horses after intravenous administration.

Abstract: The pharmacokinetics of diphenhydramine (DPHM) was compared in camels (n = 8) and horses (n = 6) following intravenous (i.v.) administration of a dose of 0.625 mg/kg body weight. In addition, the metabolism and urinary detection time of DPHM was evaluated in camels. The data obtained (median and range in brackets) in camels and horses, respectively, were as follows. The terminal elimination half lives (h) were 1.58 (1.13-2.58) and 6.11 (4.80-14.1), and the total body clearances (L/h per kg) were 1.42 (1.13-1.74) and 0.79 (0.66-0.90). The volumes of distribution at steady state (L/kg) were 2.38 (1.58-4.43) and 5.98 (4.60-8.31) and the volumes of the central compartment of the two compartment pharmacokinetic model were 1.58 (0.80-2.54) and 2.48 (1.79-3.17). All the pharmacokinetic parameters in camels were significantly different from those of horses. Five metabolites of DPHM were tentatively identified in the camel's urine. Two metabolites, diphenylmethoxyacetic acid and 1-(4-hydroxyphenyl)-phenylmethoxyacetic acid, were present in the acid fraction. Two metabolites, desamino-DPHM and diphenylmethanol, were identified in the basic fraction, in addition to DPHM itself, which was present mainly as a conjugate. Even after enzymatic hydrolysis, DPHM could be detected for up to 24 h in camels after an i.v. dose of 0.625 mg/kg body weight.
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Publication Date: 2003-10-30 PubMed ID: 14582745DOI: 10.1023/a:1025789607863Google Scholar: Lookup
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  • Comparative Study
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The researchers conducted a study to compare how the drug diphenhydramine (commonly used for allergic reactions and insomnia) is processed in the bodies of camels and horses. They found significant differences in how the two species metabolize the drug, and they were able to identify several by-products of the drug in the camel’s urine.

Research Methodology

  • The research focuses on the pharmacokinetics, or how the body absorbs, distributes, metabolizes, and excretes a drug, of diphenhydramine (DPHM) in camels and horses.
  • Eight camels and six horses were involved in the study. Each animal received an intravenous dose of DPHM at 0.625 mg/kg body weight.
  • The researchers evaluated the terminal elimination half-life, total body clearance, volume of distribution at steady state, and volume of the central compartment of the pharmacokinetic model in both species.
  • They also studied the metabolism and urinary detection time of DPHM in camels, identifying five metabolites in urine.

Key Findings

  • The terminal elimination half-lives, which represent the time it takes for the drug’s concentration in the body to reduce by half, were significantly shorter in camels (1.58 hours) compared to horses (6.11 hours).
  • The total body clearances, which indicate how fast the drug is removed from the body, were faster in camels (1.42 L/h per kg) than in horses (0.79 L/h per kg).
  • The volumes of distribution at steady state, showing the theoretical volume that would be necessary to contain the total amount of an administered drug at the same concentration observed in blood plasma, were lower in camels (2.38 L/kg) compared to horses (5.98 L/kg).
  • The volume of the central compartment of the two-compartment pharmacokinetic model, which is used to describe the way a drug moves within the body, was smaller in camels (1.58) than in horses (2.48).
  • All pharmacokinetic parameters in camels were significantly different from those in horses, suggesting substantial species differences in the metabolism of DPHM.
  • Five metabolites of DPHM were identified in the camels’ urine, including diphenylmethoxyacetic acid, 1-(4-hydroxyphenyl)-phenylmethoxyacetic acid, desamino-DPHM, and diphenylmethanol, along with DPHM itself. The dominant form of DPHM was as a conjugate.
  • Even after enzymatic hydrolysis, a process that breaks down substances, DPHM could be detected in camels’ urine up to 24 hours after intravenous administration of a dose at 0.625 mg/kg body weight.

Cite This Article

APA
Wasfi IA, Abdel Hadi AA, Elghazali M, Alkateeri NA, Hussain MM, Hamid AM. (2003). Comparative pharmacokinetics of diphenhydramine in camels and horses after intravenous administration. Vet Res Commun, 27(6), 463-473. https://doi.org/10.1023/a:1025789607863

Publication

Veterinary research communications
ISSN: 0165-7380
NlmUniqueID: 8100520
Country: Switzerland
Language: English
Volume: 27
Issue: 6
Pages: 463-473

Researcher Affiliations

Wasfi, I A
  • Camelracing Laboratory, Forensic Science Laboratory, PO Box 253, Abu Dhabi, United Arab Emirates. iawasfi@emirates.net.ae
Abdel Hadi, A A
    Elghazali, M
      Alkateeri, N A
        Hussain, M M
          Hamid, A M

            MeSH Terms

            • Acetates / urine
            • Animals
            • Area Under Curve
            • Benzhydryl Compounds / urine
            • Camelus / metabolism
            • Camelus / urine
            • Diphenhydramine / administration & dosage
            • Diphenhydramine / pharmacokinetics
            • Diphenhydramine / urine
            • Doping in Sports / prevention & control
            • Female
            • Gas Chromatography-Mass Spectrometry / veterinary
            • Half-Life
            • Histamine H1 Antagonists / administration & dosage
            • Histamine H1 Antagonists / pharmacokinetics
            • Histamine H1 Antagonists / urine
            • Horses / metabolism
            • Horses / urine
            • Injections, Intravenous / veterinary
            • Male
            • Metabolic Clearance Rate

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            This article includes 14 references
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            Citations

            This article has been cited 1 times.
            1. Smith JS, Viall AK, Breuer RM, Walton RA, Plummer PJ, Griffith RW, Kreuder AJ. Preliminary Investigation of Bovine Whole Blood Xenotransfusion as a Therapeutic Modality for the Treatment of Anemia in Goats. Front Vet Sci 2021;8:637988.
              doi: 10.3389/fvets.2021.637988pubmed: 33748213google scholar: lookup
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