A study which compared 75 mg pethidine administered via intravenous injection (IV) and 100 mg administered orally (PO) to 10 mg oxycodone (IV) and 10 mg (PO), 10 mg morphine (IV) and 20 mg (PO), 2 mg hydromorphone (IV) and 4 mg (PO), and placebo (C) in the subjects self-reported subjective effects such as drug-liking (how many of the subjects enjoyed or not, the experience; if yes, what was the most enjoyable part and why?, etc.) and how eagerly did subject want to re-experience it, and after IV doses were administered, pethidine 75 mg second-highest rates of drug-liking, after morphine 10 mg. Descriptive adjectives for morphine by subjects were:  “more sedating”, “more relaxing” and in comparison to the others, many subjects described that the experience was “more intense”. Pethidine followed, then hydromorphone, oxycodone and last was placebo. Upon oral administration, preference went from (greatest>least): oxycodone 10 mg>morphine 20 mg>hydromorphone 4 mg>pethidine 100 mg>placebo. The especially severe side effects unique to pethidine among opioids—serotonin syndrome, seizures, delirium, dysphoria, tremor—are primarily or entirely due to the action of its metabolite, norpethidine. Pharmacokinetics
Pethidine is quickly hydrolysed in the liver to pethidinic acid and is also demethylated to norpethidine, which has half the analgesic activity of pethidine but a longer elimination half-life (8–12 hours); accumulating with regular administration, or in kidney failure. Norpethidine is toxic and has convulsant and hallucinogenic effects.
In regions of the world where the disease is common eflornithine is provided for free by the World Health Organization. Research
Trypanosomiasis could, in future be prevented by genetically altering the tsetse fly. As the tsetse fly is the main vector of transmission, making the fly immune to the disease by altering its genome could be the main component in an effort to eradicate the disease. New technologies such as CRISPR allowing cheaper and easier genetic engineering could allow for such measures. A pilot program in Senegal, funded by the International Atomic Energy Agency, has considerably reduced the tsetse fly population by introducing male flies which have been sterilized by exposure to gamma rays. This has allowed a change of cattle breeds from lower producing trypanotolerant breeds to higher-producing foreign breeds, and was selected as one of the Best Sustainable Development Practices on Food Security by EXPO Milan 2015. Other animals
Nagana, or animal African trypanosomiasis, also called Souma or Soumaya in Sudan. Surra
Mal de cadeiras, or Quebra Bunda (of central South America, Brazil)
Murrina de caderas (of Panama;  Derrengadera de caderas)
Dourine
Cachexial fevers (various)
Gambian horse sickness (of central Africa)
Baleri  (of Sudan)
Kaodzera  (Rhodesian trypanosomiasis)
Tahaga  (a disease of camels in Algeria)
Galziekte, galzietzke (bilious fever of cattle; gall sickness of South Africa)
Peste-boba (of Venezuela; Derrengadera)Some species of cattle such as the African buffalo, Ndama, and Keteku appear trypanotolerant and do not develop symptoms. Calves are more resistant than adults.Tsetse-borne species of trypanosomes have entered zoos outside the traditional tsetse zone in infected animals imported for the zoo.