Meperidine 261cally toward driving skills, however, led researchers to conclude that people
should not operate a motor vehicle for 24 hours after an intramuscular injec-
tion of meperidine. Anyone with enlarged prostate, urinary difficulty, Addi-
son’s disease, or underactive thyroid should be wary about using the drug.
An unusual case report tells of a patient developing Parkinson’s disease symp-
toms from meperidine; more commonly such reports arise from contaminated
illicit substances related to meperidine. Another illicit peril occurs when per-
sons grind up and inject oral meperidine tablets; the talc in those tablets can
block tiny blood vessels throughout the body and also cause those vessels to
bleed—serious business in the eyes or brain. Illicit intramuscular injection of
the drug over a period of years can cause muscle damage. Injecting into an
artery can lead to gangrene.
Abuse factors.Meperidine tolerance occurs. Dependence may develop faster
than with morphine, but meperidine’s withdrawal syndrome may be briefer;
symptoms also tend to be more limited than with morphine, perhaps just
muscle spasms and unrest. When medical personnel are withdrawing addicts
fromheroin, meperidine has enough cross-tolerance to control withdrawal
symptoms.
Drug interactions.Meperidine should be avoided by persons taking mon-
oamine oxidase inhibitors (MAOIs, found in some antidepressants). That com-
bination can be dangerous or even fatal.Alcoholand other depressants should
be used carefully with meperidine in order to avoid cumulative overdose.
Amphetamines boost pain relief provided by meperidine. The HIV/AIDS (hu-
man immunodeficiency virus/acquired immunodeficiency syndrome) drug ri-
tonavir is believed to lengthen a meperidine dose, meaning that too much of
the opioid could build up in a person who is on a normal meperidine medi-
cation schedule. Experiments with the ritonavir-meperidine combination,
however, have shown the risk to be less than expected. Air pressure affects a
meperidine dose; the higher the altitude, the longer a dose lasts.Phenobar-
bital, the antipsychotic drug chlorpromazine (Thorazine), and the heartburn-
ulcer medicine cimetidine interfere with meperidine. Brewer’s yeast is said to
produce a bad reaction with meperidine, such as raising blood pressure so
high that a medical emergency occurs.
Cancer.One analysis of medical records in Great Britain found a statistical
association between receiving meperidine at birth and subsequent develop-
ment of childhood cancer. A statistical association, however, simply provides
guidance for future research and does not demonstrate cause and effect. Anal-
ysis of a different and smaller set of records found no association.
Pregnancy.An experiment on pregnant mice produced no birth defects def-
initely attributable to the drug, but meperidine has caused congenital malfor-
mations in hamsters. Medical records from a few dozen women who used
meperidine during pregnancy revealed no congenital malformations attrib-
utable to the substance. If a pregnant woman takes the drug, it will pass into
the fetus, where the substance tends to build up. Difficulties have not been
seen in infants from such women unless the drug has been administered dur-
ing childbirth. In those latter cases a respiratory emergency can occur in in-
fants who acquired the drug during birth, and less serious newborn behavioral
abnormalities are common. Rhesus monkeys who received fetal exposure at