ipronidazole

The story

1. Ancient Greekῐ̓́σος (ĭ́sos)
2. Englishiso-
3. Frenchpropionique
4. Proto-Indo-European*swel-der.?
5. Ancient Greekῡ̔́λη (hū́lē)
6. Frenchpropyl-
7. Englishpropyl
8. Englishisopropyl
9. Proto-Indo-European*médʰu
10. Proto-Hellenic*métʰu
11. Ancient Greekμέθυ (méthu)
12. Ancient Greekῡ̔́λη (hū́lē)
13. GermanMethy
14. Englishme(thyl)
15. Egyptiannṯr
16. Egyptiannṯrj
17. Ancient Greekνῐ́τρον (nĭ́tron)
18. Englishnitro-
19. Egyptianjmn
20. Ancient GreekᾸ̓́μμων (Ắmmōn)
21. LatinAmmōn
22. Latinammoniacus
23. Englishammonia
24. Proto-Indo-European*dʰeh₁-
25. Englishamide
26. Englishimide
27. Proto-Indo-European*né
28. Proto-Indo-European*n̥-
29. Proto-Hellenic*ə-
30. Ancient Greekᾰ̓- (ă-)
31. Proto-Indo-European*gʷeyh₃-
32. Proto-Indo-European*gʷih₃wós
33. Proto-Indo-European*gʷíh₃weti
34. Proto-Hellenic*gʷyṓw-ō
35. Proto-Hellenic*d͏̌ṓwō
36. Ancient Greekζώω (zṓō)
37. Ancient Greekζῶ (zô)
38. Ancient Greekζωή (zōḗ)
39. Frenchazote
40. Englishazote
41. Englishazo-
42. Englishazole
43. Englishimidazole
44. Englishmetronidazole
45. English todayipronidazole

From i(so)pro(pyl) + -nidazole (“metronidazole derivative”).