6 Clinical Trials for Various Conditions
Grapefruit juice is an inhibitor of the cytochrome P450 (CYP) 3A4 enzyme system, one of the enzyme systems responsible for the metabolism of colchicine. This study will evaluate the effect of multiple daily consumptions of grapefruit juice on the pharmacokinetic profile of a single 0.6 mg dose of colchicine. A secondary objective is to evaluate the safety and tolerability of this regimen in healthy volunteers. All study subjects will be monitored for adverse events throughout the study period.
Seville orange juice is an inhibitor of the intestinal cytochrome P450 (CYP) 3A4 enzyme, one of the enzymes responsible for the metabolism of colchicine. This study will evaluate the effect of multiple daily consumptions of Seville orange juice on the pharmacokinetic profile of a single 0.6 mg dose of colchicine. A secondary objective is to evaluate the safety and tolerability of this regimen in healthy volunteers. All study subjects will be monitored for adverse events throughout the study period.
This proposed Phase 2 The Small Business Innovation Research study is a randomized trial of the effectiveness of "A Toast to Health in Later Life!" a web-based patient educational program designed to prevent hazardous and harmful drinking in older adults. The project's specific objectives are to 1. provide reliable information on the extent to which "A Toast to Health in Later Life!" reduces alcohol-related risks and problems among older patients who drink and 2. evaluate the extent to which these reductions are associated with increases in health-related quality of life, patient knowledge and self-efficacy and decreases in the use of health services and the costs of care.
The purpose of this study is to evaluate a well-characterized, commercially available cinnamon dietary supplement as a precipitant of pharmacokinetic interactions with cytochrome P450 (CYP) 2A6 drug substrates in healthy volunteers. Nicotine gum will be used as the CYP2A6 probe drug (i.e., positive control) and letrozole as a high-impact object drug. Results will be used to inform future research on the potential use of cinnamon as a smoking cessation agent, as well as the clinical impact on pharmacotherapeutic regimens involving letrozole in cancer patients.
Kratom is a botanical natural product that has opioid-like effects. Kratom is commonly used to self-treat withdrawal symptoms associated with opioid addiction, as well as pain. Kratom products include pills, extracts, and powders, most of which contain two primary psychoactive constituents: mitragynine and 7-hydroxymitragynine. Preliminary data from the investigator's laboratory has shown that these two constituents and extracts made from commercially available kratom products are strong inhibitors of the drug metabolizing enzymes cytochrome P450 (CYP) 2D6 and CYP3A4. These enzymes are responsible for metabolizing more than 50% of marketed drugs, including several opioids, benzodiazepines, and antidepressants. Thus, co-consumption of kratom products with drugs metabolized by CYP2D6 and CYP3A4 could increase the risk of serious adverse effects. The effects of a well-characterized kratom product on CYP2D6 and CYP3A4 activity will be assessed in healthy volunteers using a 'cocktail' approach consisting of the validated probe drugs dextromethorphan and midazolam. Results will (1) provide useful information regarding risks associated with co-consuming kratom with opioids and other CYP2D6 and CYP3A4 drug substrates and (2) inform the design of future kratom-drug interactions studies.
Goldenseal is a botanical natural product commonly used to self-treat symptoms of the common cold and many digestive disorders. Goldenseal products typically contain the isoquinoline alkaloids berberine, hydrastine, and hydrastinine. These constituents contain a methylenedioxyphenyl ring, a 'structural alert' that can lead to irreversible inhibition of drug metabolizing enzymes, particularly the cytochromes P450 (CYPs). Clinical studies involving healthy volunteers demonstrated that, compared to baseline (absence of goldenseal), CYP2D6 and CYP3A activities were reduced by 40-60% following treatment with goldenseal. Compared to the CYPs, the effects of goldenseal products on drug transporters are understudied, particularly in human subjects. Using a 'cocktail' consisting of 'probe' drug substrates for CYP3A and various transporters, the effects of goldenseal on the pharmacokinetics of each probe drug will be examined in healthy volunteers. Results will provide useful information about the risk of co-consuming goldenseal with additional drugs that are substrates for transporters.