Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jul 31;15(15):2256.
doi: 10.3390/ani15152256.

Preliminary Pharmacokinetics and Appetite Stimulant Efficacy of Oral Mirtazapine in Guinea Pigs (Cavia porcellus)

Jessica Ayers  1 , Elizabeth Stietzle  2 , Megan Ellis  3 , Jeffrey Kim  4 , Lon V Kendall  1
Affiliations

Preliminary Pharmacokinetics and Appetite Stimulant Efficacy of Oral Mirtazapine in Guinea Pigs (Cavia porcellus)

Jessica Ayers et al. Animals (Basel). .

Abstract

Guinea pigs used in research may experience inappetence or decreased intestinal motility, which can significantly compromise their welfare. This study evaluates the use of mirtazapine on appetite and intestinal motility in guinea pigs. An initial pharmacokinetics and efficacy study was performed using healthy male guinea pigs administered mirtazapine at 1.88, 3.75, or 7.5 mg orally once daily for four days (n = 6), in a crossover design where all animals received all doses. Body, feed, and fecal weights were taken daily for 4 days. There were no significant differences in weight gains, feed intake, or fecal output as compared to guinea pigs given saline only (n = 3). Blood was collected under anesthesia at 0, 0.5, 1, 2, 8, 12, and 24 h post-administration. Pharmacokinetic analysis completed after the first dose showed peak plasma levels at 30 min, then falling below the limit of detection between 8 h and 12 h at all doses. Based on the pharmacokinetic profile, a follow-up study was performed in another set of healthy male guinea pigs with every 8 h dosing at 1.88 mg orally for 5 days (n = 6). There was a significant increase in feed intake during mirtazapine administration as compared to baseline intake, but no significant difference in weight gains. This study shows that mirtazapine can be used as an appetite stimulant in guinea pigs but must be dosed at least every eight hours to be effective.

Keywords: anorexia; appetite; guinea pig; inappetence; mirtazapine.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Mean (+ SD) plasma mirtazapine concentrations (µg/mL) after 1.88 mg, 3.75 mg, and 7.5 mg oral dosing in male guinea pigs.
Figure 2
Figure 2
Average (± SD) daily guinea pig weight change (g/day) during once daily oral mirtazapine dosing.
Figure 3
Figure 3
Average (± SD) daily guinea pig fecal weights (g/day) during once daily oral mirtazapine dosing.
Figure 4
Figure 4
Average (± SD) daily guinea pig feed intake (g/day) during once daily oral mirtazapine dosing.
Figure 5
Figure 5
Average (+ SD) daily guinea pig feed consumption and weight gain during q. 8 h oral mirtazapine dosing, * denotes significance compared to baseline.
See this image and copyright information in PMC

Similar articles

  • Prescription of Controlled Substances: Benefits and Risks.
    Preuss CV, Kalava A, King KC. Preuss CV, et al. 2025 Jul 6. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. 2025 Jul 6. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. PMID: 30726003 Free Books & Documents.
  • The Black Book of Psychotropic Dosing and Monitoring.
    DeBattista C, Schatzberg AF. DeBattista C, et al. Psychopharmacol Bull. 2024 Jul 8;54(3):8-59. Psychopharmacol Bull. 2024. PMID: 38993656 Free PMC article. Review.
  • Sertindole for schizophrenia.
    Lewis R, Bagnall AM, Leitner M. Lewis R, et al. Cochrane Database Syst Rev. 2005 Jul 20;2005(3):CD001715. doi: 10.1002/14651858.CD001715.pub2. Cochrane Database Syst Rev. 2005. PMID: 16034864 Free PMC article.
  • Heliox for croup in children.
    Moraa I, Sturman N, McGuire TM, van Driel ML. Moraa I, et al. Cochrane Database Syst Rev. 2021 Aug 16;8(8):CD006822. doi: 10.1002/14651858.CD006822.pub6. Cochrane Database Syst Rev. 2021. PMID: 34397099 Free PMC article.
  • Mirtazapine as Appetite Stimulant in Patients With Non-Small Cell Lung Cancer and Anorexia: A Randomized Clinical Trial.
    Arrieta O, Cárdenas-Fernández D, Rodriguez-Mayoral O, Gutierrez-Torres S, Castañares D, Flores-Estrada D, Reyes E, López D, Barragán P, Soberanis Pina P, Cardona AF, Turcott JG. Arrieta O, et al. JAMA Oncol. 2024 Mar 1;10(3):305-314. doi: 10.1001/jamaoncol.2023.5232. JAMA Oncol. 2024. PMID: 38206631 Free PMC article. Clinical Trial.
See all similar articles

References

    1. Dyson R.M., Palliser H.K., Kelleher M.A., Hirst J.J., Wright I.M. The guinea pig as an animal model for studying perinatal changes in microvascular function. Pediatr. Res. 2012;71:20–24. doi: 10.1038/pr.2011.9. - DOI - PubMed
    1. Hensel M.E., Arenas-Gamboa A.M. A Neglected Animal Model for a Neglected Disease: Guinea Pigs and the Search for an Improved Animal Model for Human Brucellosis. Front. Microbiol. 2018;9:2593. doi: 10.3389/fmicb.2018.02593. - DOI - PMC - PubMed
    1. Orme I.M. Mouse and guinea pig models for testing new tuberculosis vaccines. Tuberc. Edinb. Scotl. 2005;85:13–17. - PubMed
    1. Padilla-Carlin D.J., McMurray D.N., Hickey A.J. The guinea pig as a model of infectious diseases. Comp. Med. 2008;58:324–340. - PMC - PubMed
    1. Chiou P.W.S., Yu B., Kuo C.Y. Comparison of digestive function among rabbits, guinea-pigs, rats and hamsters. I. Performance, digestibility and rate of digesta passage. Asian-Australas. J. Anim. Sci. 2000;13:1499–1507. doi: 10.5713/ajas.2000.1499. - DOI

LinkOut - more resources