A Phase 4 interventional study of Trimethoprim and Metformin in Vitamin B1 Deficiency and Thiamine Deficiency, sponsored by University of California, San Francisco. Completed at 1 site in United States. Open to participants aged 18 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-01-03.
Sponsored by University of California, San Francisco · Phase 4, Interventional, and Basic science
In Part 1, subjects will be administered thiamine, thiamine with metformin, and thiamine with trimethoprim. Part 2 will expand on Part 1 and subjects will be administered thiamine and thiamine with trimethoprim. The goal is to determine whether taking a drug and a vitamin together affects the body's ability to absorb, distribute, and eliminate thiamine (Vitamin B1).
Thiamine is an essential vitamin meaning humans must consume thiamine from their diet in order to stay healthy. Low thiamine levels can lead to adverse events. Thiamine is absorbed in the intestine by a transporter protein. This is made by the SLC19A3 gene. The SLC19A3 gene provides instructions for making the thiamine transporter protein, which moves thiamine into cells. Certain drugs, like metformin and trimethoprim, have been shown to interrupt function of the SLC19A3 gene.
Metformin is a first-line therapy for patients with Type 2 diabetes and is associated with improvements in diabetic complications. Trimethoprim is an anti-bacterial drug that is often prescribed to treat infections such as urinary tract infections. At different phases of this study, participants will be administered thiamine, thiamine with metformin, and/or thiamine with trimethoprim to determine whether taking a drug and a vitamin together affects the body's ability to absorb, distribute, and eliminate thiamine. The levels of thiamine in the participants' blood and urine will be measured before and after taking thiamine or thiamine in combination with metformin and/or trimethoprim.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
5mg thiamine tablet by mouth. This arm will be included in both Parts 1 and 2 of the study.
Dietary Supplement: Vitamin B1
5mg thiamine tablet and 300mg trimethoprim tablet by mouth. This arm will be included in both Parts 1 and 2 of the study.
Drug: Trimethoprim · Dietary Supplement: Vitamin B1
5mg thiamine tablet and 1000mg metformin tablet by mouth. This arm will be included in only Part 1 of the study.
Drug: Metformin · Dietary Supplement: Vitamin B1
300mg of trimethoprim will be given in combination with 5mg thiamine and compared to 5mg thiamine only for both Parts 1 and 2 of the study.
Also known as: Primsol
1000mg of metformin will be given in combination with 5mg thiamine and compared to 5mg thiamine only in Part 1 of the study.
Also known as: Glucophage
5mg of thiamine will be given alone and in combination for both Parts 1 and 2 of the study.
Also known as: Thiamine
Maximum Concentration (Cmax) of Thiamine in Plasma Between the Combination Arm(s) and Single Agent Arm
Plasma samples were collected at pre-dose and 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 10, 12, and 24 hours post-dose for each cycle. Cmax is determined by taking blood samples at various time points after drug administration and analyzing the thiamine concentration in plasma.
Time frame: The highest concentration of a thiamine observed in the blood plasma after drug administration
Area Under the Curve From 0 to 24 (AUC0-24)Hours of Thiamine in Plasma Between the Combination Arm(s) and Single Agent Arm
Plasma samples were collected at pre-dose and 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 10, 12, and 24 hours post-dose for each cycle. AUC0-24 (Area Under the Curve from 0 to 24 hours) is a pharmacokinetic (PK) parameter that represents the total drug exposure in the body over a 24-hour period. It is calculated as the area under the plasma thiamine concentration vs. time curve (from time zero to 24 hours after drug administration).
Time frame: Plasma samples were collected at pre-dose and 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 10, 12, and 24 hours post-dose for each cycle.
| Milestone | Thiamine Alone, Then Thiamine Co-administered With Trimethoprim | Thiamine Co-administered With Trimethoprim, Then Thiamine Alone |
|---|---|---|
| Started | 4 | 3 |
| Completed | 4 | 3 |
| Not completed | 0 | 0 |
| Milestone | Thiamine Alone, Then Thiamine Co-administered With Trimethoprim | Thiamine Co-administered With Trimethoprim, Then Thiamine Alone |
|---|---|---|
| Started | 4 | 3 |
| Completed | 4 | 3 |
| Not completed | 0 | 0 |
Plasma samples were collected at pre-dose and 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 10, 12, and 24 hours post-dose for each cycle. Cmax is determined by taking blood samples at various time points after drug administration and analyzing the thiamine concentration in plasma.
| nM | Thiamine Alone | Thiamine Co-administered With Trimethoprim |
|---|---|---|
| Maximum Concentration (Cmax) of Thiamine in Plasma Between the Combination Arm(s) and Single Agent Arm | 15 ± 9.5 | 32 ± 22 |
Plasma samples were collected at pre-dose and 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 10, 12, and 24 hours post-dose for each cycle. AUC0-24 (Area Under the Curve from 0 to 24 hours) is a pharmacokinetic (PK) parameter that represents the total drug exposure in the body over a 24-hour period. It is calculated as the area under the plasma thiamine concentration vs. time curve (from time zero to 24 hours after drug administration).
| nM*hr | Thiamine Alone | Thiamine Co-administered With Trimethoprim |
|---|---|---|
| Area Under the Curve From 0 to 24 (AUC0-24)Hours of Thiamine in Plasma Between the Combination Arm(s) and Single Agent Arm | 50 ± 30 | 189 ± 138 |
Collected over Two cycles (which were separated by a washout period of 5-14 days) and each cycle was three days in duration.. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Thiamine Alone | 0/7 (0%) | 0/7 (0%) | 0/7 (0%) |
| Thiamine Co-administered With Trimethoprim | 0/7 (0%) | 0/7 (0%) | 0/7 (0%) |
| Age, Continuous(years) | Thiamine Alone, Thiamine Co-administered With Trimethoprim |
|---|---|
| Mean | 46 ± 15 |
| Sex: Female, Male(Participants) | Thiamine Alone, Thiamine Co-administered With Trimethoprim |
|---|---|
| Female | 4 |
| Male | 3 |
| Ethnicity (NIH/OMB)(Participants) | Thiamine Alone, Thiamine Co-administered With Trimethoprim |
|---|---|
| Hispanic or Latino | 2 |
| Not Hispanic or Latino | 5 |
| Unknown or Not Reported | 0 |
| Race (NIH/OMB)(Participants) | Thiamine Alone, Thiamine Co-administered With Trimethoprim |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 0 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 0 |
| White | 5 |
| More than one race | 0 |
| Unknown or Not Reported | 2 |
| Weight(kg) | Thiamine Alone, Thiamine Co-administered With Trimethoprim |
|---|---|
| Mean | 76 ± 16 |
| Height(cm) | Thiamine Alone, Thiamine Co-administered With Trimethoprim |
|---|---|
| Mean | 170 ± 7.3 |
| BMI(kg/m^2) | Thiamine Alone, Thiamine Co-administered With Trimethoprim |
|---|---|
| Mean | 26.4 ± 4.6 |
| Baseline Thiamine (Thiamine arm)(nM) | Thiamine Alone, Thiamine Co-administered With Trimethoprim |
|---|---|
| Mean | 12.3 ± 24.0 |
1 further baseline measures are reported on the registry.
PDFs hosted by the registry, ClinicalTrials.gov.
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Studies of the drug tested here: Thiamine
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