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Study · Randomized controlled trial · n = 44 · 2022

14 results

Evaluation of the abuse potential of difelikefalin, a selective kappa-opioid receptor agonist, in recreational polydrug users.

Shram MJ, Spencer RH, Qian J, Munera CL, Lewis ME, Henningfield JE, Webster L, Menzaghi F

Clinical and translational science28 Oct 2021Cited by 24 (Europe PMC)

PMID34708917 (opens in a new tab)PMCIDPMC8841457 (opens in a new tab)DOI10.1111/cts.13173 (opens in a new tab)PepBankPUB-34708917
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Summary

The text of this summary is not shown here, because the article license does not allow reuse. Read it at the source (opens in a new tab)

Text rights: CC BY-NC-ND. Results still quote short attributed sentences.

Results from this study14

14 results from studies that gave the peptide. 14 results from people.

  1. 01HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, difelikefalin produced significantly lower peak Drug Liking VAS scores than pentazocine.

    In plain wordsIn recreational polydrug users, peak drug liking was significantly lower with difelikefalin than pentazocine.

    Peptide
    Difelikefalin
    Outcome
    DecreasePeak Drug Liking VAS
    Study

    n = 44

    Comparator
    Pentazocine
    Analysis
    Primary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    Difelikefalin produced significantly lower Drug Liking VAS Emax , and lower peak positive, sedative, and perceptual effects compared with pentazocine.
    2 context sentences
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  2. 02HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, difelikefalin drug-liking effects were small, brief, not dose-dependent, and marginally greater than placebo.

    In plain wordsIn recreational polydrug users, difelikefalin drug-liking effects were small and brief, but marginally greater than placebo.

    Peptide
    Difelikefalin
    Outcome
    IncreasePeak Drug Liking VAS
    Study

    n = 44

    Comparator
    Placebo
    Analysis
    Primary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    These effects of difelikefalin were small, brief, and not dose-dependent, although marginally greater than those observed with placebo.
    3 context sentences
    Summary · context
    Difelikefalin produced significantly lower Drug Liking VAS Emax , and lower peak positive, sedative, and perceptual effects compared with pentazocine.
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  3. 03HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, difelikefalin produced lower peak positive effects than pentazocine.

    In plain wordsIn recreational polydrug users, peak positive effects were lower with difelikefalin than pentazocine.

    Peptide
    Difelikefalin
    Outcome
    DecreasePeak positive effects
    Study

    n = 44

    Comparator
    Pentazocine
    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    Difelikefalin produced significantly lower Drug Liking VAS Emax , and lower peak positive, sedative, and perceptual effects compared with pentazocine.
    2 context sentences
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  4. 04HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, difelikefalin produced lower peak sedative effects than pentazocine.

    In plain wordsIn recreational polydrug users, peak sedation was lower with difelikefalin than pentazocine.

    Peptide
    Difelikefalin
    Outcome
    DecreasePeak sedative effects
    Study

    n = 44

    Comparator
    Pentazocine
    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    Difelikefalin produced significantly lower Drug Liking VAS Emax , and lower peak positive, sedative, and perceptual effects compared with pentazocine.
    2 context sentences
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  5. 05HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, difelikefalin produced lower peak perceptual effects than pentazocine.

    In plain wordsIn recreational polydrug users, peak perceptual effects were lower with difelikefalin than pentazocine.

    Peptide
    Difelikefalin
    Outcome
    DecreasePeak perceptual effects
    Study

    n = 44

    Comparator
    Pentazocine
    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    Difelikefalin produced significantly lower Drug Liking VAS Emax , and lower peak positive, sedative, and perceptual effects compared with pentazocine.
    2 context sentences
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  6. 06HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, difelikefalin positive effects were small, brief, not dose-dependent, and marginally greater than placebo.

    In plain wordsIn recreational polydrug users, difelikefalin positive effects were small and brief, but marginally greater than placebo.

    Peptide
    Difelikefalin
    Outcome
    IncreasePeak positive effects
    Study

    n = 44

    Comparator
    Placebo
    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    These effects of difelikefalin were small, brief, and not dose-dependent, although marginally greater than those observed with placebo.
    3 context sentences
    Summary · context
    Difelikefalin produced significantly lower Drug Liking VAS Emax , and lower peak positive, sedative, and perceptual effects compared with pentazocine.
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  7. 07HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, difelikefalin sedative effects were small, brief, not dose-dependent, and marginally greater than placebo.

    In plain wordsIn recreational polydrug users, difelikefalin sedative effects were small and brief, but marginally greater than placebo.

    Peptide
    Difelikefalin
    Outcome
    IncreasePeak sedative effects
    Study

    n = 44

    Comparator
    Placebo
    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    These effects of difelikefalin were small, brief, and not dose-dependent, although marginally greater than those observed with placebo.
    3 context sentences
    Summary · context
    Difelikefalin produced significantly lower Drug Liking VAS Emax , and lower peak positive, sedative, and perceptual effects compared with pentazocine.
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  8. 08HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, difelikefalin perceptual effects were small, brief, not dose-dependent, and marginally greater than placebo.

    In plain wordsIn recreational polydrug users, difelikefalin perceptual effects were small and brief, but marginally greater than placebo.

    Peptide
    Difelikefalin
    Outcome
    IncreasePeak perceptual effects
    Study

    n = 44

    Comparator
    Placebo
    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    These effects of difelikefalin were small, brief, and not dose-dependent, although marginally greater than those observed with placebo.
    3 context sentences
    Summary · context
    Difelikefalin produced significantly lower Drug Liking VAS Emax , and lower peak positive, sedative, and perceptual effects compared with pentazocine.
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  9. 09HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, end-of-session overall drug liking with difelikefalin did not differ from placebo.

    In plain wordsIn recreational polydrug users, overall liking of difelikefalin did not differ from placebo.

    Peptide
    Difelikefalin
    Outcome
    No significant changeOverall drug liking
    Study

    n = 44

    Comparator
    Placebo
    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    On end-of-session measures of overall drug liking and willingness to take the drug again, difelikefalin did not differ from placebo, indicating subjects neither liked nor disliked the effects overall and did not feel motivated to take the drug again.
    2 context sentences
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  10. 10HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, willingness to take difelikefalin again did not differ from placebo.

    In plain wordsIn recreational polydrug users, willingness to take difelikefalin again did not differ from placebo.

    Peptide
    Difelikefalin
    Outcome
    No significant changeWillingness to take drug again
    Study

    n = 44

    Comparator
    Placebo
    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    On end-of-session measures of overall drug liking and willingness to take the drug again, difelikefalin did not differ from placebo, indicating subjects neither liked nor disliked the effects overall and did not feel motivated to take the drug again.
    2 context sentences
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  11. 11HumanRandomized controlled trialSafety outcome

    In recreational polydrug users, difelikefalin did not induce miosis compared with pentazocine.

    In plain wordsIn recreational polydrug users, difelikefalin did not constrict pupils compared with pentazocine.

    Peptide
    Difelikefalin
    Outcome
    DecreaseMiosis
    Study

    n = 44

    Comparator
    Pentazocine
    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    Consistent with its lack of mu agonist activity, difelikefalin did not induce miosis compared with pentazocine.
    2 context sentences
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  12. 12HumanNon-randomized trialSafety outcome

    In recreational polydrug users, neither difelikefalin dose elicited significant negative effects.

    In plain wordsIn recreational polydrug users, neither difelikefalin dose produced significant negative effects.

    Peptide
    Difelikefalin
    Outcome
    No significant changeNegative effects
    Study

    n = 44

    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    Neither dose of difelikefalin elicited significant negative or hallucinogenic effects.
    2 context sentences
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  13. 13HumanNon-randomized trialSafety outcome

    In recreational polydrug users, neither difelikefalin dose elicited significant hallucinogenic effects.

    In plain wordsIn recreational polydrug users, neither difelikefalin dose produced significant hallucination-related effects.

    Peptide
    Difelikefalin
    Outcome
    No significant changeHallucinogenic effects
    Study

    n = 44

    Analysis
    Secondary
    Outcome group
    Adverse events · Nervous system and cognition
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    Neither dose of difelikefalin elicited significant negative or hallucinogenic effects.
    2 context sentences
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)
  14. 14HumanNon-randomized trialSafety outcome

    In recreational polydrug users, difelikefalin and all other treatments were generally well tolerated.

    In plain wordsIn recreational polydrug users, difelikefalin and all other treatments were generally well tolerated.

    Peptide
    Difelikefalin
    Outcome
    Not applicableGeneral tolerability
    Study

    n = 44

    Outcome group
    Adverse events · Whole body
    Studied dose
    5 and 15 mcg/kg · intravenous · single injectionAs given in this study (human).

    Source sentences

    Summary
    All treatments were generally well-tolerated.
    2 context sentences
    Summary · context
    This randomized, double-blind, active- and placebo-controlled, four-way crossover study was designed to evaluate the abuse potential of difelikefalin in healthy recreational polydrug users.
    Summary · context
    Using a 4 × 4 Williams design, nondependent adult users of opioids and hallucinogens (N = 44) were randomized to receive single intravenous (i.v.) injections of difelikefalin at supratherapeutic doses (5 and 15 mcg/kg)

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

  1. Version 2Current

    28 Oct 2026, 02:03 UTC

    Study results updated

  2. Version 1

    27 Oct 2026, 16:35 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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