Effect of Lofexidine and Oral THC on Marijuana Withdrawal and Relapse

New York State Psychiatric Institute

Status and phase

Completed

Phase 2

Conditions

Marijuana Dependence

Treatments

Drug: dronabinol

Drug: Marijuana

Drug: Lofexidine

Study type

Interventional

Funder types

Other

NIH

Identifiers

NCT00373503

4942

R01DA019239 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

The purpose of this study is to investigate the interaction between marijuana and two potential treatment medications: lofexidine and oral THC, with the direct goal of using this information to improve marijuana treatment outcome.

Full description

Only a small percentage of dependent-marijuana smokers who are seeking treatment for their marijuana use is able to achieve sustained abstinence. The objective of this study is to investigate the interaction between marijuana and two potential treatment medications: lofexidine and oral THC, with the direct goal of using this information to improve marijuana treatment outcome. In mice, the α2-receptor agonist, clonidine, reversed symptoms of cannabinoid withdrawal (Lichtman et al., 2001). The purpose of this study is to determine if lofexidine, an α2-receptor agonist with a more favorable side-effect profile than clonidine, decreases symptoms of marijuana withdrawal and thus decreases marijuana relapse, as compared to placebo. Oral THC is FDA-approved for appetite enhancement. Lofexidine, which is currently not FDA-approved, is used in Europe to treat symptoms of heroin withdrawal, and to treat hypertension. For the purposes of this model, relapse is defined to a return to marijuana use after a period of abstinence. We have shown that oral THC reduces symptoms of marijuana withdrawal at doses that produce minimal intoxication (Haney et al., 2004). Thus, the effects of oral THC alone and in combination with lofexidine will be determined. The study will utilize an inpatient/outpatient, counter-balanced design, with each participant maintained on each of four medication conditions for 8 days each: placebo, lofexidine, oral THC, and oral THC combined with lofexidine. During the inpatient study phases, participants will have the opportunity to self-administer placebo or active marijuana 6 times per day. Outpatient phases are for medication clearance so no medications will be administered. This study will provide important information of the effect of these potential treatment medications on both marijuana withdrawal symptoms, and on subsequent marijuana self-administration.

Enrollment

8 patients

Sex

All

Ages

21 to 45 years old

Volunteers

Accepts Healthy Volunteers

Inclusion criteria

Current marijuana use: average of 3 marijuana cigarettes at least 4 times per week for the past 4 weeks
Able to perform study procedures
21-45 years of age
Women practicing an effective form of birth control (condoms, diaphragm, birth control pill, IUD)

Exclusion criteria

Current, repeated illicit drug use (other than marijuana)
Presence of significant medical illness (e.g., diabetes, cardiovascular disease, hypertension, clinically significant laboratory abnormalities)
Bradycardia (55 beats/minute), hypotension (< 90 mmHg) including orthostatic hypotension (> 20 mmHg decrease in SP, or > 10 mmHg decrease in DP upon standing
History of heart disease
Request for drug treatment
Current parole or probation
Pregnancy or current lactation
Recent history of significant violent behavior
Major current Axis I psychopathology (e.g., major depressive disorder, bipolar disorder,suicide risk, schizophrenia)
Current use of any prescription or over-the-counter medication