In which of the following poisoning, gastric lavage is indicated even through the route of poisoningis parenteral?

In opiate poisoning, gastric lavage first with tepid water (the returning fluid kept for analysis)and then with the solution (1:5000) of potassium permanganate needs to be performed. This tends to oxidize opium into harmless substances. Even when the drug has been administered through injection, the permanganate treatment should be adopted since morphine is excreted in the stomach. Some solution should be left in the stomach with the aim of oxidizing the alkaloid that might be so excreted. Ref - Krishan Vij textbook of forensic medicine and toxicology 5e pg : 491