Methadone and nicotine self-administration in humans: a behavioral economic analysis.
BACKGROUND
Prior research has revealed inconsistencies in the behavioral relations between nicotine and opiates among methadone-maintained patients.


OBJECTIVE
The current study examined whether the drug reinforcers cigarette puffs and methadone were economic complements or substitutes.


METHODS
Five methadone-maintained, nicotine-dependent participants were trained to self-administer methadone, cigarette puffs, or concurrently available methadone and puffs. Following training, the fixed ratio (FR) value ("price") was increased across sessions (FR 32, 64, 128, 256, and 512), first for methadone and then for puffs. Subsequently, methadone and puffs were concurrently available, and the price of each drug was increased independently, while the price of the alternative (puffs or methadone) remained constant at FR 32.


RESULTS
Demand for methadone and cigarette puffs decreased as a function of increases in methadone and cigarette puff prices, respectively. When methadone and puffs were concurrently available, an increase in methadone's price decreased puff consumption, and demand for methadone was less elastic than when puffs were not concurrently available. An increase in puff price decreased puff and methadone demand, but the elasticity of puff demand was unaffected. The concurrent presence of methadone had no effect on the elasticity of demand for cigarette puffs.


CONCLUSIONS
Methadone and cigarette puffs appear to be asymmetric economic complements.
Spiga
Ralph
R
Department of Psychiatry and Behavioral Sciences, Temple University Health System, 100 East Lehigh Avenue, Suite 305, Philadelphia, PA 19125-1098, USA. rspiga@temple.edu
Martinetti
Margaret P
MP
Meisch
Richard A
RA
Cowan
Katherine
K
Hursh
Steven
S
D000328:Adult; D002755:Choice Behavior; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004347:Drug Interactions; D005260:Female; D006801:Humans; D008297:Male; D008691:Methadone / Q000008:administration & dosage*; D009042:Motivation; D009294:Narcotics / Q000008:administration & dosage*; D009293:Opioid-Related Disorders / Q000523:psychology / Q000534:rehabilitation*; D012055:Reinforcement Schedule; D012646:Self Administration / Q000523:psychology; D012907:Smoking / Q000523:psychology*; D016540:Smoking Cessation / Q000523:psychology; D015813:Substance Abuse Detection / Q000523:psychology; D014029:Tobacco Use Disorder / Q000523:psychology*
D009294:Narcotics; D008691:Methadone