Nifedipine Ketanserin

Two patients experienced an increase in cardiac arrhythmias when they were given ketanserin with nifedipine. 

A study in 20 subjects aged 60 years or more, with normal or slightly raised blood pressures, found that the concurrent use of ketanserin and nifedipine for a week did not, on average, affect their blood pressures, heart rates, or QT intervals, but two of the subjects monitored over 24 hours showed a marked increase in the frequency of ectopic beats, couplets and ventricular tachycardia. The reasons are not understood. The authors of this study say that their findings do not exclude the possibility that the concurrent use of these two drugs might therefore increase arrhythmia in some elderly patients. Concurrent use should be monitored. 

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