Parasite killer Ivermectin stops cancer drug resistance 24 November 2019
A widely available insecticide, Ivermectin, has been shown to make drug-resistant tumours and leukaemia immediately responsive to the drugs; this is not the first time anti-cancer activity has been shown, with previous research on breast, ovarian, lymphoma and TNBC, plus studies showing improved response to Adriamycin and Taxol.
All drugs are required to have an expiration date. Like most drugs, the 2 year date probably means Jack shit.
Most drugs just get weaker with time. Ivermectin has such a high safety factor that it's very hard to overdose. You can just increase the dosage if you are concerned about it losing effectiveness over time.
Actual limiting factor is probably bacteria growth. If you can avoid that, maybe indefinite...