102 Codeine
months went by, but the increase was caused by decline of their physical
condition rather than development of tolerance.
The same study noted that almost no patients abused the drug, and of those
few who did, all abused other substances as well. That finding is consistent
with many observations of other drugs having abuse potential; only a small
minority of users misuse them, and this minority is prone to problems with
more than one substance. People having a bad relationship with codeine tend
to have bad relationships with alcohol,marijuana, and (less commonly)her-
oin. One study found that almost half the patients requesting treatment for
codeine cough syrup addiction engaged in sexual conduct putting them at
risk for AIDS, conduct illustrating a multiproblem lifestyle in which codeine
abuse was simply one aspect. Background checks of deceased Los Angeles–
area codeine abusers revealed almost 66% had attempted suicide, had a prior
overdose on some drug, had been hospitalized for psychiatric problems, had
been in physical fights, and had an alcohol problem (87% had an alcohol-
related arrest record). So codeine may be only one of several problems in such
lives.
Not all drug abuse is illicit. Sometimes people develop an abusive relation-
ship with a drug that is supplied to them through legitimate medical channels.
Swedish researchers compared the use of codeine in that country to the use
ofpropoxyphene, an opioid related tomethadone. Those investigators found
that doctors in two of Sweden’s largest cities typically tended to prescribe
codeine to middle-aged females and that in one of those cities codeine was
used the most in poor areas of town and was often associated with taking
benzodiazepines frequently (in experiments the benzodiazepine diazepam
lengthened the time that a codeine dose lasted, while codeine interfered with
diazepam—suggesting that a codeine user would have to take more diazepam
to get benzodiazepine sensations, consistent with the Swedish findings of in-
creased benzodiazepine consumption among codeine users). Those kinds of
codeine usage characteristics were not found for propoxyphene in the Swedish
research even though both drugs would have opiate-type effects; the differ-
ence in usage suggests that physicians’ customs may have been promoting
codeine abuse.
In drug abuse treatment programs codeine has been used successfully to
shift addicts from other opiates—so successfully that one group of researchers
suggests that codeine maintenance programs might be an alternative to meth-
adone maintenance, particularly because codeine produces fewer unwanted
effects than methadone.
Drug interactions.The antidepressants fluoxetine (Prozac) and paroxetine
interfere with the body’s transformation of codeine into morphine; therefore,
persons taking those antidepressants are considered less likely to develop co-
deine abuse (because they would experience fewer effects from codeine). Al-
though codeine is weaker than morphine, similarities between the two drugs
mean that interactions occurring with morphine can be expected to occur with
codeine.
Cancer.Laboratory tests find no evidence that the drug causes cell muta-
tions that might lead to cancer. Experimenters gave codeine to rats and mice
for two years and looked for evidence of cancer caused by the drug but found