I
- Ibogaine
- Ibuprofen
- Ibutramoren
- Iclazepam
- IDRA-21
- Ifenprodil
- Ifosfamide
- Iloperidone
- Imatinib
- Imazalil
- Imazaquin
- Imidacloprid
- Imidapril
- Imipramine
- Imipramine, oxide
- Imolamine
- Indacaterol
- Indalpine
- Indane
- Indapamide
- Indinavir
- Indomethacin
- Iodorphine
- Ioxinyl
- Ipamorelin
- iPDMB-FUBINACA
- IPO-33
- Ipratopium
- Iprobenfos
- iPRONE
- Iproniazide
- Irbesartan
- Irinotecan
- Iso-(meta-methyl-propcathinone)
- iso-(metamethyl-propcathinone)
- Iso-3-CMC
- iso-Butonitazene
- Iso-ethcathinone
- Isobutyl-pentyl-1H-indazole-3-carboxylate
- Isobutyryl fentanyl
- Isobutyryl norfentanyl
- Isobutyrylfentanyl (iBF)
- Isocarbophos
- Isocarboxazid
- Isocarfentanil
- Isoconazole
- Isohexedrone
- Isohexylone
- Isoniazid
- Isopentedrone
- Isophenmetrazine
- Isoprenaline
- Isoprocarb
- Isopropamide +
- Isopropyl U-47700
- Isopropylphenidate
- Isoprothiolane
- Isoproturon
- Isotodesnitazene
- Isotonitazene
- Isotonitrazine
- Isotretinoin
- Isovaleryl Fentanyl
- Isradipine
- Itraconazole
- Ivabradine