8 Clinical Trials for Various Conditions
The goal of this study is to investigate whether the botanical product kratom affects how the body processes the opioid drug oxycodone. The main research questions to be answered are two-fold: 1. How does kratom affect the manner in which oxycodone is metabolized (broken down and removed) by the body? 2. Does kratom change the effects oxycodone exerts on the body? Healthy adult participants will complete four study arms, during which they will be given the following: * Kratom (as a tea) * A single dose of oxycodone (as a tablet) * Kratom tea and a single dose of oxycodone * Kratom tea for four days, then kratom tea and a single dose of oxycodone
The purpose of this study is to determine if the use of herbal products interferes with normal anticoagulation, leading to either excessive thinning of the blood and bleeding problems or inadequate thinning of the blood and clotting problems. Many patients who are on long term anticoagulation, or blood thinning, for a variety of medical problems, also take herbal products. It is not yet known whether use of herbal products interferes with this anticoagulation, and puts patients at risk for bleeding or clotting. This study will carefully monitor patients who are taking herbs and anticoagulants to determine if their laboratory tests show signs of being affected by the herbs. The study will ask all patients about their herbal product use, so all reported herbs will be included and monitored.
The study is being conducted to evaluate whether African potato, an herbal medicine, can be used together with anti-HIV medicines without affecting the amounts of the anti-HIV medicines in the blood. African potato is an African herbal medicine widely used in Africa, particularly sub-Saharan Africa. Although it has not been proven, it is believed to help boost the immune system. Similar studies have been done on herbal medicines especially those that are used in developing countries. In some cases, the herbal treatments can affect the blood levels of other medicines when the medicines are used together. This study will measure the effect of African potato on lopinavir/ritonavir (Kaletra®), a common anti-HIV medicine. Lopinavir/ritonavir is approved by the United States Food and Drug Administration (FDA). The information obtained from this study will tell us if African potato and anti-HIV treatments can be used together to treat HIV infected patients in Africa and other resource poor regions.
This is a 4-week sequential drug interaction study to measure the effects of American ginseng on efavirenz pharmacokinetics using steady-state 24-hour Area Under the Curve (AUC) and Cmax as the primary comparison measures in healthy male volunteers. Efavirenz Cmin, T1/2, tmax, and clearance will also be assessed as secondary outcome measures. This study is a phase I, prospective, within-subject, fixed-order, two-period, multiple dose, open label, drug interaction study, to determine the stead-state plasma pharmacokinetic profile of efavirenz before and after concurrent treatment with American ginseng. The investigators hypothesis is that concurrent oral administration of American ginseng for up to 14 days will not significantly alter the steady-state plasma pharmacokinetic of efavirenz.
This study will examine the interaction of the HIV combination medication lopinavir/ritonavir with the herbal products echinacea, ginseng, and ginkgo biloba. Patients with HIV infection often take herbal products and dietary supplements in addition to their doctor-prescribed medicines to treat the disease, lessen the side effects of anti-viral drugs, and improve their overall well being. Alternative medicines such as these may, however, interfere with the elimination of lopinavir/ritonavir from the body, causing either higher or lower blood levels of these drugs than would be expected. This study will assess in healthy subjects any potential harms of taking echinacea, ginseng, or ginkgo biloba together with lopinavir/ritonavir. Healthy normal volunteers between 18 and 50 years of age may be eligible for this study. Candidates are screened with a history, physical examination, and blood tests, including an HIV test and a pregnancy test for women. Pregnant women are excluded from the study. Participants come to the NIH Clinical Center after fasting overnight for the following procedures: Visits 1 and 2: A catheter (plastic tube) is placed in an arm vein to collect blood samples. After the first sample is drawn, the subject takes 8 mg of midazolam syrup and two fexofenadine tablets. Midazolam is a sedative, and fexofenadine (Allegra) is a medicine used to treat allergies. Subjects are given breakfast an hour after taking the drugs. Blood samples are collected at 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 8 and 24 hours after taking the drugs to measure blood levels of fexofenadine. An extra sample is collected at the 4-hour mark to measure the midazolam level. The catheter is removed after the 8-hour blood draw and subjects are dismissed home. They return the following morning (visit 2) for the 24-hour blood draw. Visit 3: From 7 to 28 days after visit 1, subjects begin taking lopinavir/ritonavir capsules twice a day by mouth for a total of 29.5 days. On day 15 they return to the clinic for lopinavir/ritonavir blood levels as were done for fexofenadine, except that samples are collected once before breakfast and then at 0.5, 1, 2, 3, 4, 6, 8 and 12 hours after the lopinavir/ritonavir dose. An extra sample is collected for routine tests. The catheter is removed after the 12-hour draw and the subject is dismissed home. The next morning, subjects begin taking one of the following: echinacea 500 mg 3 times a day; ginkgo biloba 120 mg twice a day; or ginseng 500 mg 3 times a day for 28 days. Visit 4: On the last day of taking lopinavir/ritonavir, subjects return to the clinic again for blood level measurements of these drugs as on visit 3, except that the catheter is removed and the subject dismissed home after the 8-hour blood draw. Visits 5 and 6: On the last day of taking the herbal supplement, subjects return to the clinic for repeat measurement of fexofenadine and midazolam levels, as described in visits 1 and 2. At the final visit (visit 6) an additional blood sample is collected for repeat laboratory testing. ...
St. John's Wort is a popular dietary supplement that many patients-including those with epilepsy or seizures-take in addition to their regular medicines to elevate mood or relieve stress. Preliminary research indicates that this supplement can speed the metabolism of the anti-seizure drug Tegretol, causing reduced blood levels of the drug. Patients who take Tegretol to control their seizures may have more frequent seizures if the blood level of the drug drops too low. A recent study shows that this effect is not seen when Tegretol is taken for at least 3 weeks. The present study will examine whether there is a medically important drug interaction between St. John's wort and Tegretol when Tegretol is taken for 1 day. Normal healthy volunteers between 21 and 65 years old who are not taking medicines that can affect the metabolism of drugs in the liver and have not used St. John's wort for at least 30 days may be eligible for this 25-day study. Participants will take a 400-mg dose of Tegretol after fasting overnight. Blood samples will be drawn the next day during a 12-hour clinic stay at the following intervals: just before the Tegretol dose and at 1, 2, 4, 6, 8, 10, 24, 34, 48 and 72 hours after the dose. A catheter will be placed in the vein to prevent the need for multiple needle sticks until after the 10-hour sample. After completing the blood sampling, participants will take 300 mg of St. John's wort 3 times a day with meals for 2 weeks. After 2 weeks, another fasting dose of Tegretol will be given and the 72-hour blood study will be repeated. This study may provide information important for the care of patients with epilepsy who take both Tegretol and St. John's Wort.
This study will examine how the herbal remedy ginkgo biloba may affect the body's elimination of other medicines. Many people take ginkgo biloba to improve memory, mental alertness and overall feeling of well being. Since this product is considered a food supplement and not a drug, it is not subject to the rigorous pre-market testing required for prescription and over-the-counter (OTC) drugs. As a result, information has not been collected on possible interactions between ginkgo biloba and other medications. This study will look at how ginkgo biloba affects the elimination of phenytoin-a medication used to treat patients with seizures. Normal healthy volunteers 21 years of age or older may be eligible for this 40-day study. Candidates will provide a medical history and undergo a physical examination and routine blood tests. Women of childbearing age must use a reliable form of birth control other than oral contraceptives ("the pill"). For at least 2 weeks before the study and throughout its duration, study participants may not have any of the following: 1) medications that can affect platelet function (e.g., aspirin, Motrin, Advil, Nuprin, ibuprofen, etc.); 2) alcoholic beverages; 3) grapefruit and grapefruit juice; and 4) all medications except those given by study personnel. On day 1 of the study, subjects take one 500-mg dose of phenytoin at 8:00 A.M.. On an empty stomach. (Subjects fast the night before taking the phenytoin and are allowed to eat breakfast 2 hours after the dose). Blood samples are drawn just before dosing and again at 0.5, 1, 1.5, 2, 4, 6, 8, 10, 12, 24, 32, 48, 72 and 96 hours after the dose. Blood drawn on this first study day is collected through a catheter (small plastic tube) placed in a vein to avoid multiple needlesticks. After the 12-hour sample is collected, the subject goes home and then returns to the clinic for the remaining blood draws, which are taken by direct needlestick. When the blood sampling is completed, subjects begin ginkgo therapy. The NIH Clinical Center provides participants a supply of 60-mg capsules of ginkgo to take twice a day (at 8 A.M. and 8 P.M..) for 4 weeks. At the end of the 4 weeks, subjects are given a second dose of phenytoin as described above and repeat the blood sampling procedure. Subjects continue taking ginkgo during this second phenytoin study.
This study will examine how kava-a widely used herbal remedy-may affect the body's elimination of other medicines. Many people take kava to reduce anxiety or cause sedation. Since this product is considered a food supplement and not a drug, it is not subject to the rigorous pre-market testing required for prescription and over-the-counter (OTC) drugs. As a result, information has not been collected on possible interactions between kava and other medications. This study will look at how kava affects the elimination of caffeine-a compound commonly found in chocolate, coffee, tea and soft drinks-and dextromethorphan-an OTC cough suppressant. Normal healthy volunteers 21 years of age or older may be eligible for this 30-day study. Candidates will provide a medical history and undergo a physical examination and routine blood tests. Women of childbearing age will have a urine pregnancy test. Study participants will not drink alcoholic beverages or take any medications (except those given in the study) for 2 weeks prior to the study and throughout its duration. In addition, they will abstain from caffeine, grapefruit and grapefruit juice and charbroiled foods for at least 72 hours before and throughout each study day that urine is collected. On day 1 of the study, study subjects will take one dose each of caffeine and dextromethorphan at 4:00 P.M.. They will empty their bladder before the dosing and then collect all their urine after the dosing for the rest of the day and including the next mornings first urine. They will bring the urine samples to the Clinical Center when the collection is complete. This procedure will be repeated 1 week later (study day 8). After the second urine collection is completed, subjects will take 200 milligrams of kava 3 times a day for 21 days. On study day 29 (after 21 days of kava), subjects will repeat the dextromethorphan and caffeine dosing and urine collection described above, while continuing to take kava. Subjects will have an electroencephalograph (EEG) done before starting kava and again at the end of kava (study day 30). For this procedure, several electrodes (metal cups attached to wires) are secured to the scalp with a glue-like substance. A conductive gel fills the space between the electrode and the scalp to ensure good contact. The electrodes will remain in place for about 2 hours and then removed. The subject lies quietly on a bed during the EEG recording. Participation in the study will end with another physical examination and blood tests following the second EEG and urine collection.