title: Interaction between verapamil and beta-methyldigoxin. Study by 86Rubidium uptake in erythrocytes.
abstract: Digoxin and Verapamil may often be used in association in heart diseases; we tested whether this coadministration increases digitalis activity. Ten patients with failing heart were given 0.10 mg of beta-methyldigoxin, twice a day, for nine days; then they received in addition 80 mg of Verapamil, four times a day, for seven days. Digoxin activity was measured on the eighth, ninth and 16th days of treatment by 86Rubidium uptake in erythrocytes. The steady-state concentration was 0.91 +/- 0.13 ng/ml; during the coadministration the concentration rose to 1.23 +/- 0.16 ng/ml (an increase of 35.12%). The change was significant (p less than 0.001). The mechanism of this increase is unknown: it is important that there exists an increase in digitalis activity and not only a haematic elevation.
mesh_terms: D000368:Aged; D004077:Digoxin / Q000031:analogs & derivatives*; D004347:Drug Interactions; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008520:Medigoxin / Q000494:pharmacology*; D008875:Middle Aged; D011868:Radioisotopes; D012413:Rubidium; D013997:Time Factors; D014700:Verapamil / Q000494:pharmacology*
chemical_list: D011868:Radioisotopes; D004077:Digoxin; D014700:Verapamil; D008520:Medigoxin; D012413:Rubidium