Possible Interaction: Adenosine and Nifedipine

“Interaction between nifedipine and adenosine should be kept in mind when treating patients with nifedipine.”

“It is probable that nifedipine exerts part of its physiological actions through potentiation of adenosine.”

“ Adenosine , in concentrations achieved in the plasma during myocardial ischemia (0.01-0.1 microM), enhanced the inhibitory effects of nifedipine , verapamil and diltiazem on platelet aggregation 5-100 fold.”

“In the presence of non-inhibitory concentrations of adenosine, nifedipine , in concentrations approaching those attained in vivo following standard therapeutic doses (as low as 0.29 microM), significantly inhibited thromboxane A2-induced platelet aggregation.”

“This interaction might be due to the inhibitory effects of nifedipine and Bay K 8644 on the uptake of adenosine by rat brain.”

“Concurrent administration of verapamil with adenosine neither affected the hyperglycaemic nor the hypoinsulinaemic effects of adenosine, whereas combined administration of nifedipine and adenosine decreased the hyperglycaemic effect of adenosine but not its hypoinsulinaemic effect.”

“2 Nifedipine and Bay K 8644, a calcium channel antagonist and activator respectively, enhanced the inhibitory action of adenosine in a concentration‐dependent manner.”

“4 Addition of the adenosine uptake blocker dipyridamole reversed the action of nifedipine on adenosine, so that inhibition by adenosine was now attenuated by nifedipine in a similar manner to that observed with the adenosine analogues.”

“Several analogues of adenosine which are not substrates for the uptake system also depressed the population spikes in the CA1 region but these responses were inhibited by nifedipine and BAYK 8644.”

“Previous pharmacologic studies indicating competitive interactions between adenosine and nifedipine at the adenosine vascular receptor suggest that adenosine may he a less effective hypotensive drug after pretreatment with nifedipine.”

“The present findings may have clinical relevance in patients with cardiovascular disease being treated with nifedipine who may need adenosine to lower blood pressure either to decrease bleeding or to decrease myocardial work and oxygen consumption.”

“In contrast to receptor-binding studies requiring high ratios of the drugs to adenosine receptor radioligands, nifedipine and nisoldipine were inhibitory at equimolar concentrations with adenosine.”

“ Nifedipine decreased the release of adenosine , inosine and (hypo)-xanthine during ischemia and reperfusion.”

“Furthermore, the negative interaction of nifedipine and adenosine in vivo suggests that these agents might act differently in an in vitro setting.”

“The calcium channel blocker nifedipine attenuates the coronary response to adenosine infusion and reactive hyperemia in dogs.”