Increased risk of hip fracture in the elderly associated with prochlorperazine: is a prescribing cascade contributing?
OBJECTIVE
To examine the prescribing of prochlorperazine secondary to the prescribing of a medicine which could lead to symptoms for which prochlorperazine is indicated and commonly used. Given the range of potential hypotensive, sedative, dystonic and other extra-pyramidal side effects associated with prochlorperazine, its association with hip fracture was also examined.


METHODS
Prescription/event sequence symmetry analyses were undertaken from 1st January 2003 to 31st December 2006, using administrative claims data from the Department of Veterans' Affairs, Australia. This method assesses asymmetry in the distribution of an incident event (either prescription of another medicine or hospitalization) before and after the initiation of prochlorperazine. Crude and adjusted sequence ratios (ASR) with 95% confidence intervals (CI) were calculated.


RESULTS
A total of 34 235 persons with incident use of prochlorperazine were identified during the study period. Statistically significant positive associations were found for a number of commonly used medicines, including cardiovascular medicines, NSAIDs, opioids and sedatives and the subsequent initiation of prochlorperazine that ranged from 1.07 (95%CI 1.01-1.14) for diuretics to 1.50 (95%CI 1.40-1.61) for statins. Prescription event analysis showed a 49% (95%CI 1.19-1.86) increased risk of hospitalisation for hip fracture following dispensing of prochlorperazine.


CONCLUSIONS
Prescribers should consider the possible contributing role of newly initiated medicines with the potential to cause of dizziness, and where possible address this through dose reduction or cessation of the medicine, rather than prescribing prochlorperazine.
Caughey
Gillian E
GE
Quality Use of Medicines and Pharmacy Research Centre, Sansom Institute, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA, Australia. gillian.caughey@unisa.edu.au
Roughead
Elizabeth E
EE
Pratt
Nicole
N
Shakib
Sepehr
S
Vitry
Agnes I
AI
Gilbert
Andrew L
AL
D000368:Aged; D000369:Aged, 80 and over; D000932:Antiemetics / Q000009:adverse effects* / Q000627:therapeutic use; D001315:Australia / Q000453:epidemiology; D016208:Databases, Factual; D004244:Dizziness / Q000139:chemically induced / Q000175:diagnosis / Q000188:drug therapy; D064420:Drug-Related Side Effects and Adverse Reactions; D005260:Female; D006620:Hip Fractures / Q000139:chemically induced*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D009325:Nausea / Q000139:chemically induced / Q000175:diagnosis / Q000188:drug therapy; D004364:Pharmaceutical Preparations / Q000008:administration & dosage; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D011346:Prochlorperazine / Q000009:adverse effects* / Q000627:therapeutic use; D012306:Risk; D014728:Veterans
D000932:Antiemetics; D004364:Pharmaceutical Preparations; D011346:Prochlorperazine