Suspended

L-tetrahydropalmatine (l-THP) Treatment for Cocaine Use Disorder

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What is being tested

l-tetrahydropalmatine (l-THP)

+ Placebo
Drug
Who is being recruted

From 18 to 50 Years
See all eligibility criteria
How is the trial designed

Treatment Study

Placebo-Controlled
Phase 2
Interventional
Study Start: September 2014
See protocol details

Summary

Principal SponsorUniversity of Maryland, Baltimore
Last updated: January 18, 2026
Sourced from a government-validated database.Claim as a partner
Study start date: September 1, 2014Actual date on which the first participant was enrolled.

Cocaine continues to be one of the most widely used substances of abuse around the world. In the US, an estimated 1.4 million individuals (0.5%) > 12 years were current (past month) cocaine users in 2011. Currently, no FDA-approved pharmacologic treatments are available for cocaine addiction; thus, this remains a serious public health problem without an effective pharmacological treatment. A promising lead towards an effective treatment comes from a recent finding that pretreatment with oral l-tetrahydropalmitine (l-THP) in rats attenuated the cocaine seeking associated with a cocaine challenge, while having no motor effects. This finding stimulated our group to test the pharmacokinetics and safety of l-THP in a phase I study of people with cocaine use. Preliminary findings show l-THP is safe and well tolerated in cocaine users, with no adverse interactions with cocaine. This study will test the efficacy and safety of l-THP for abstinence in those with cocaine addiction in a phase II pilot study (N=24). Secondarily, we will examine the effects of these medications on craving.

Official TitleL-tetrahydropalmatine (l-THP) Treatment for Cocaine Use Disorder 
NCT02139761
Principal SponsorUniversity of Maryland, Baltimore
Last updated: January 18, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Treatment Study
These studies test new ways to treat a disease, condition, or health issue. The goal is to see if a new drug, therapy, or approach works better or has fewer side effects than existing options.

How participants are assigned to different groups/arms
In this clinical study, participants are placed into groups randomly, like flipping a coin. This ensures that the study is fair and unbiased, making the results more reliable. By assigning participants by chance, researchers can better compare treatments without external influences.

Other Ways to Assign Participants
Non-randomized allocation: Participants are assigned based on specific factors, such as their medical condition or a doctor's decision.
None (Single-arm trial): If the study has only one group, all participants receive the same treatment, and no allocation is needed.

How treatments are given to participants
Participants are divided into different groups, each receiving a specific treatment at the same time. This helps researchers compare how well different treatments work against each other.

Other Ways to Assign Treatments
Single-group assignment: Everyone gets the same treatment.
Cross-over assignment: Participants switch between treatments during the study.
Factorial assignment: Participants receive different combinations of treatments.
Sequential assignment: Participants receive treatments one after another in a specific order, possibly based on individual responses.
Other assignment: Treatment assignment does not follow a standard or predefined design.

How the effectiveness of the treatment is controlled
In a placebo-controlled study, some participants receive the experimental treatment, while others receive an inert substance (placebo) to compare outcomes. This method helps to isolate the effect of the treatment from the psychological effects of receiving any treatment at all.

Other Options
Non-placebo-controlled: No placebo is used. All participants receive the actual treatment or alternative interventions (often the Standard of Care), and comparisons are made between these treatments.

How the interventions assigned to participants is kept confidential
Participants, researchers, outcome assessors, and care providers do not know which treatment is being given. This is the most complete way to prevent bias and keep the study as neutral as possible.

Other Ways to Mask Information
Open-label: Everyone knows which treatment is being given.
Single-blind: Participants do not know which treatment they are receiving, but researchers do.
Double-blind: Neither participants nor researchers know which treatment is given.
Triple-blind: Participants, researchers, and outcome assessors do not know which treatment is given.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Criteria
Any sexBiological sex of participants that are eligible to enroll.
From 18 to 50 YearsRange of ages for which participants are eligible to join.
Healthy volunteers not allowedIf individuals who are healthy and do not have the condition being studied can participate.
Criteria

Inclusion Criteria: * men or non-pregnant/non-nursing women between the ages of 18 and 50 years * meeting criteria for DSM-5 cocaine use disorder * self-reported cocaine use (intranasal, IV or smoked) averaging at least weekly for the prior six months positive urine drug test for cocaine in the prior month * HIV seronegative * EKG without clinically significant abnormality * normal blood pressure (systolic: 90-140 mmHg; diastolic: 50-90 mmHg) and resting heart rate (60-90 bpm) * ability to adhere to the study restrictions and examination schedule * women with reproductive potential must agree to the use of one of the following birth control methods (oral contraceptives, condom with spermicide, diaphragm, or intrauterine device) during the study and for 2 weeks after last medication dose. Exclusion Criteria: * participation in any investigational drug trial or clinical drug trial within 45 days before study entry * history of clinically significant adverse reaction or hypersensitivity to cocaine or l-THP * inability to communicate or co-operate with the investigators * currently taking any prescribed psychoactive medication, e.g., anti- depressant, anti-psychotic, or mood stabilizer * current clinically significant medical problem that might interfere with safe study participation. This includes pheochromocytoma, untreated hyperthyroidism, dehydration, fever, coronary artery disease, uncorrected congenital heart defect, seizures, electrolyte imbalance, uncontrolled diabetes mellitus, porphyria variegate, superventricular tachycardia, atrial fibrillation, cardiomyopathy, or uncontrolled hypertension. * current Axis I Major Depression, Schizophrenia, or Bipolar Disorder. * score below 10/12 on the Evaluation to Sign Consent (ESC)

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives
2 intervention groups 

are designated in this study

50% chance 

of being blinded to the placebo group

Treatment Groups
Group I
Active Comparator
Subjects will be dosed 30 mg BID (2 capsules total a day, total of 60mg/day), matching placebo or l-THP) (total 60 mg daily). The half-life of l-THP is about 10 hours, so subjects will reach steady state in about 2-3 days. The l-THP will be prepared at the University of Maryland School of Pharmacy to Chemistry under Good Manufacturing Practice (GMP) and standards. The identical placebo and active capsules will be manufactured and sent to the Maryland Psychiatric Research Center Pharmacy, where they will be stored, randomized and dispensed. Medication will be transported by the study staff to the participant once dispensing occurs.

Subjects will be dosed 30 mg BID (2 capsules total a day, total of 60mg/day), matching placebo or l-THP) (total 60 mg daily). The half-life of l-THP is about 10 hours, so subjects will reach steady state in about 2-3 days. The l-THP will be prepared at the University of Maryland School of Pharmacy to Chemistry under Good Manufacturing Practice (GMP) and standards. The identical placebo and active capsules will be manufactured and sent to the Maryland Psychiatric Research Center Pharmacy, where they will be stored, randomized and dispensed. Medication will be transported by the study staff to the participant once dispensing occurs.
Group II
Placebo
Subjects will be dosed 30 mg BID (2 capsules total a day, total of 60mg/day), matching placebo or l-THP) (total 60 mg daily). The half-life of l-THP is about 10 hours, so subjects will reach steady state in about 2-3 days. The l-THP will be prepared at the University of Maryland School of Pharmacy to Chemistry under Good Manufacturing Practice (GMP) and standards. The identical placebo and active capsules will be manufactured and sent to the Maryland Psychiatric Research Center Pharmacy, where they will be stored, randomized and dispensed. Medication will be transported by the study staff to the participant once dispensing occurs.

Subjects will be dosed 30 mg BID (2 capsules total a day, total of 60mg/day), matching placebo or l-THP) (total 60 mg daily). The half-life of l-THP is about 10 hours, so subjects will reach steady state in about 2-3 days. The l-THP will be prepared at the University of Maryland School of Pharmacy to Chemistry under Good Manufacturing Practice (GMP) and standards. The identical placebo and active capsules will be manufactured and sent to the Maryland Psychiatric Research Center Pharmacy, where they will be stored, randomized and dispensed. Medication will be transported by the study staff to the participant once dispensing occurs.
Study Objectives
Primary Objectives

We will measure cocaine and its metabolite by urine drug test to assess for abstinence.

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.
This study has 1 location
Suspended
Maryland Psychiatric Research CenterCatonsville, United StatesSee the location
SuspendedOne Study Center
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