Gastric lavage may be useful in early presentations (<1-2 h postingestion), especially in cases of extended- or delayed-release tablet ingestion.
Activated charcoal (50-100 g PO) should be administered after gastric lavage.
Completely asymptomatic patients may be treated with activated charcoal and close observation.
Whole bowel irrigation with polyethylene glycol solution (eg, GoLYTELY, NuLytely, Colyte) may be useful in extended-release preparations. However, be sure that ileus, bowel obstruction, and bowel ischemia have not occurred; case reports of bowel ischemia and infarction have appeared with calcium channel blocker overdose

2011