Written by Greg Arnold, DC, CSCS. This study demonstrated that Tamiflu, when administered to rats, significantly increased ALT (liver enzyme) by 67.6% compared to control, and GGT by 71.9% in male rats and 49.8% in female rats compared to their respective controls. Researchers concluded that “using this drug [for flu prevention] would require a serious risk-to-benefit analysis, especially for high-risk patients.”
Oseltamivir (Tamiflu) is a widely used prescription drug for both the treatment and prevention. With only small amounts needed to be toxic (1) and a known track record for causing serious side effects in mice and humans that include nausea and vomiting (2), it’s been suggested that oseltamivir should only be used for severe flu cases and caution should be raised when treating high-risk groups such as children and pregnant women.
In a 2013 study (3), 24 Wistar albino rats (12 males, 12 females) weighing between 140 and 170 grams were divided into 4 groups and given a dose of osteltamivir comparable in dosage given to humans or a placebo for 5 days:
- 12 females receiving 2.2 milligrams per kilogram of bodyweight of osteltamivir
- 12 males receiving 2.2 mg/kg* of body weight of osteltamivir
- 12 females receiving a placebo (female control group)
- 12 males receiving a placebo (male control group)
The researchers found that after 5 days, those in the oseltamivir group showed evidence of liver damage, as evidenced by increased levels of liver enzymes in the blood. In males, oseltamivir use resulted in 67.6% higher levels of a liver enzyme called ALT compared to the male control group (61.44 versus 36.66 milliUnits/milliliter, p < 0.05). In addition, levels of another liver enzyme called GGT were 71.9% higher in males (73.18 versus 42.55, p < 0.05) and 49.8% higher in females (97.72 versus 65.2, p < 0.05) compared to their respective control groups. Finally, levels of a type of fat in the blood called triacylgycerol was 68.6% higher in the male oseltamivir group (145 vs 86 milligrams/deciliter, p < 0.05) and 107% higher in the female osteltamivir group (118 versus 57 mg/dL, p < 0.05) compared to the control groups.
For the researchers, “male rats are more vulnerable than female rats to developing adverse effects in response to treatment with oseltamivir” and that “using this drug [for flu prevention] would require a serious risk-to-benefit analysis, especially for high-risk patients.”
*equivalent to 0.35mg/kg in humans and 24.5 mg for a 154 lb person. The normal does for influenza is 75 mg per day for 10 days.
Source: El-Sayed, Wael M., and Mohamed Ali Al-Kahtani. “Potential adverse effects of oseltamivir in rats: males are more vulnerable than females.” Canadian journal of physiology and pharmacology 89.9 (2011): 623-630.
Posted April 13, 2015. r/aj
References:
- Gubareva, L.V., Kaiser, L., and Hayden, F.G. 2000. Influenza virus neuraminidase inhibitors. Lancet, 355(9206): 827–835. doi:10.1016/S0140-6736(99)11433-8. PMID:10711940.
- Ono, H., Nagano, Y., Matsunami, N., Sugiyama, S., Yamamoto, S., and Tanabe, M. 2008. Oseltamivir, an anti-influenza virus drug, produces hypothermia in mice. Biol. Pharm. Bull. 31(4): 638–642. doi:10.1248/bpb.31.638. PMID:18379055
- El-Sayed WM. Potential adverse effects of oseltamivir in rats: males are more vulnerable than females. Can J Physiol Pharmacol 2011 Aug 23. [Epub ahead of print]
