Cimetidine

Caution: this drug increases the potency of other drugs and supplements by inhibiting their metabolism through the CYP450 enzyme and hence leading to higher concentrations in the blood.
This could be good if you’re taking 222 mg Fenbendazole as you want higher concentrations in the blood.
This wouldn’t be good if you’re taking drugs like Warfarin or chemo drugs.
Why is Cimetidine in this list.
Well, Cimetidine can have immune-modulating effects.
Enhances T-cell activity, promotes NK cell function, and inhibits certain inflammatory cytokines.
It has been used off-label in the treatment of certain cancers, particularly colorectal cancer, because of its potential to improve the immune system’s ability to recognize and attack tumor cells.
There is evidence suggesting cimetidine may reduce metastasis and tumor growth, likely due to its immune-boosting effects. 
There have been testimonials that Cimetidine alone was enough to cure stage 4 cancers (Rectal cancer stage 4)
Another testimony was with Cimetidine + Fenbendazole (squamous cell tonsil stage 4)
Cimetidine contains imidazole and so does Fenbendazole.
What is imidazole you might ask. 
Imidazole is a special structure that makes these drugs do their jobs better, it’s like a special helper. It’s also interesting that both of these drugs contain it so we thought, why not mention it.
Taking Cimetidine and Fenbendazole, two imidazole helpers.
Buy Cimetidine on Amazon