[Risk of drug interactions. Combinations of drugs associated with ventricular arrhythmias].
OBJECTIVE
To determine the frequency of concurrent use of cisapride, astemizole and terfenadine with macrolides and azole antimitotics, drug combinations that have been reported in the literature as producing a pharmacological interaction associated with potentially fatal ventricular arrhythmias.


METHODS
A retrospective analysis of a total of 72,444 prescriptions generated by 611 physicians during a 6 months period for ambulatory patients, was performed. The database included a register of automatic alerts produced every time a predetermined drug combination was detected.


RESULTS
145 potentially risk situations were detected, with an incidence rate to 2.1 cases per 1,000 prescriptions, which increases to 6.2% when prescriptions for terfenadine, astemizole, and cisapride were included, with 12, 9 y 5%, respectively. Only 36 physicians (6%) wrote prescriptions producing alerts, and about half (45%) were pediatricians. The same physician prescribed both drugs in 31% of the cases.


CONCLUSIONS
The use of drug combinations associated with a high risk of potentially fatal ventricular arrhythmias is relatively high in Mexico. An electronic online detecting system showed to be useful in preventing this kind of potential pharmacological interactions.
Servicio de Urgencias, Hospital de Enfermedades Cardiovasculares y del Tórax, Centro Médico del Norte, Instituto Mexicano del Seguro Social, Monterrey, NL. jose_viramontes@merck.com
José Luis
JL
Viramontes-Madrid
Carlos
C
Jerjes-Sánchez
Ingris
I
Pelaez-Ballestas
Artemisa
A
Aguilar-Chiu
Adolfo G
AG
Hernández-Garduño
D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000009:adverse effects* / Q000494:pharmacology; D000935:Antifungal Agents / Q000009:adverse effects* / Q000494:pharmacology; D001145:Arrhythmias, Cardiac / Q000139:chemically induced* / Q000453:epidemiology / Q000517:prevention & control; D016589:Astemizole / Q000009:adverse effects* / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D020117:Cisapride / Q000009:adverse effects* / Q000494:pharmacology; D003953:Diagnosis-Related Groups; D004346:Drug Information Services / Q000458:organization & administration*; D004347:Drug Interactions; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D004363:Drug Utilization / Q000706:statistics & numerical data; D005260:Female; D006634:Histamine H1 Antagonists / Q000009:adverse effects* / Q000494:pharmacology; D006801:Humans; D015994:Incidence; D007223:Infant; D018942:Macrolides; D008297:Male; D008329:Managed Care Programs / Q000458:organization & administration*; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D009862:Online Systems; D010593:Pharmaceutical Services / Q000458:organization & administration*; D010865:Pilot Projects; D012189:Retrospective Studies; D012306:Risk; D016593:Terfenadine / Q000009:adverse effects* / Q000494:pharmacology; D014230:Triazoles / Q000009:adverse effects* / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D006634:Histamine H1 Antagonists; D018942:Macrolides; D014230:Triazoles; D016593:Terfenadine; D016589:Astemizole; D020117:Cisapride