[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.
Viramontes-Madrid
José Luis
JL
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
Jerjes-Sánchez
Carlos
C
Pelaez-Ballestas
Ingris
I
Aguilar-Chiu
Artemisa
A
Hernández-Garduño
Adolfo G
AG
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