Metoclopramide Succinylcholine

Drugs that may affect metoclopramide include levodopa, anticholinergics, and narcotic analgesics. Drugs that may be affected by metoclopramide include alcohol, cimetidine, cyclosporine, digoxin, levodopa, MAO inhibitors, and succinylcholine. 

Metoclopramide increases gastric transit time, enhancing the absorption of substances absorbed in the small intestine (e.g., ethanol, cyclosporin) and decreasing the absorption of substances absorbed in the stomach (e.g., cimetidine, digoxin). Anticholinergic drugs and dopamine-function-enhancing substances such as levodopa reduce the effectiveness of metoclopramide. Because metoclopramide releases catecholamine, it should be used cautiously with monoamine oxidase inhibitors such as tranylcypromine. Because metoclopramide inhibits plasma cholinesterase, it increases the effectiveness of succinylcholine, a skeletal muscle relaxant. 

The neuromuscular blocking effects of suxamethonium (succinylcholine) and mivacurium can be increased and prolonged in patients taking metoclopramide. 

Figure 6.61 Structural formulae of metoclopramide, nicotine, psilocin and internal standard, succinylcholine, sulfasalazine, theophylline, tiagabine, tubocur-arine and vecuronium.

Absorption of digoxin in the stomach may be diminished. Absorption of oral medication (e.g. acetaminophen, levodopa, tetracycline, and ethanol) in the small bowel may be increased. Insulin dosage may require adjustment because the action of metoclopramide will influence the dehvery of food to the intestines and thus the rate of absorption. Metoclopramide increases the effect of succinylcholine and the serum levels of cyclosporine. 

---