NR207
Monday, May 23, 3:00 p.m.-5:00 p.m.
Ramelteon (TAK-375) and Triazolam
in Humans: Behavioral Effects and Abuse Potential
Roland R. Griffiths, Ph.D., Behavioral
Pharmacology Research
Unit, Johns Hopkins Bayview Medical Center, 5510 Nathan
Shock Drive, Baltimore, MD 21224; Patricia Suess, Ph.D.
Educational Objectives:
At the conclusion of this presentation, the participant should be
able to recognize that ramelteon, a novel selective melatonin MT1/MT2
receptor agonist under development for the treatment of
insomnia, shows no abuse potential as measured by multiple rating
scales widely used and accepted for abuse liability testing in novel
compounds.
Summary:
Objective: Ramelteon is a novel selective melatonin MT1/MT2 receptor
agonist under development for insomnia treatment. This study evaluated
behavioral effects and abuse potential of ramelteon
and triazolam, a classic benzodiazepine sedative-hypnotic, in subjects
with histories of sedative drug abuse.
Methods: In this double-blind, crossover study,
14 experienced drug users received one oral dose/day of ramelteon
(16mg, 80mg, 160mg), triazolam (0.25mg, 0.5mg, 0.75mg), or placebo.
Abuse potential was inferred from widely used subjective effect
questionnaires. Behavioral and cognitive performance were also assessed.
Results: Compared with placebo,
ramelteon (16mg, 80mg, 160mg) showed no significant effect on primary
outcome questionnaire item ‘‘drug liking’’ at any time point (0.5-24
hours postdose) or on items ‘‘drug strength,’’ ‘‘drug liking,’’
‘‘good effects,’’ and ‘‘street value’’ at 24 hours postdose. Similarly,
ramelteon had no effect on Word Recall/Recognition Task, Enter and
Recall Task, Balance Task, Digit Symbol Substitution Task, and Circular
Lights performance at any dose compared with placebo. In contrast,
triazolam (0.5 and 0.75mg) showed dose-related effects on all these
subjective and behavioral measures, consistent with its profile
as a sedative drug with known abuse potential.
Conclusion: Ramelteon demonstrated
no abuse potential or behavioral impairment under these study conditions
at doses up to 20 times the anticipated therapeutic dose.
References:
1. Griffiths RR, Bigelow GE, Ator NA: Principles of initial experimental
drug abuse liability assessment in humans. Drug Alcohol
Depend 2003; 70(3 Suppl):S41-S54.
2. Rush CR, Frey JM, Griffiths RR: Zaleplon and triazolam in
humans: acute behavioral effects and abuse potential. Psychopharmacology
1999; 145:39-51
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