Increased incidence of levodopa therapy following metoclopramide use
J. Avorn, J. H. Gurwitz, R. L. Bohn, H. Mogun, M. Monane and A. Walker
Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.
OBJECTIVE--To determine whether there is an increase in use of
antiparkinsonian therapy in older persons taking metoclopramide
hydrochloride. DESIGN--Case-control study. SETTING--New jersey Medicaid
program. PATIENTS--Medicaid enrollees aged 65 years and older. Cases were
patients newly prescribed a levodopa-containing medication (n = 1253); a
secondary case group were patients newly prescribed an anticholinergic
antiparkinsonian drug (n = 2377). The control group consisted of 16435
Medicaid enrollees older than 65 years who were not users of any
antiparkinsonian therapy. MAIN OUTCOME MEASURES--We used logistic
regression to determine the odds ratio (OR) for the initiation of
antiparkinsonian therapy in patients using metoclopramide relative to
nonusers, after adjusting for age, sex, race, nursing home residence,
exposure to antipsychotic medication, and days hospitalized.
RESULTS--Metoclopramide users were three times more likely to begin use of
a levodopa-containing medication compared with nonusers (OR = 3.09; 95%
confidence interval [Cl], 2.25 to 4.26). Risk increased with increasing
daily metoclopramide dose: the OR was 1.19 (95% Cl, 0.50 to 2.81) for more
than 0 to 10 mg per day, 3.33 (95% Cl, 1.98 to 5.58) for more than 10 to 20
mg per day, and 5.25 (95% Cl, 1.16 to 8.50) for more than 20mg per day. The
effect persisted after adjustment for demographic, health service
utilization, and medication use variables. The OR for initiation of
anticholinergic antiparkinsonian drugs was also elevated in metoclopramide
users. CONCLUSION--Metoclopramide use confers an increased risk for the
initiation of treatment generally reserved for the management of idiopathic
Parkinson's disease in patients with drug-induced parkinsonian symptoms,
which should be ruled out before starting dopaminergic therapy for this
condition.
