A Study of Pyrimethamine in the Treatment of Infection by a Certain Parasite in HIV-Positive Patients

Pyrimethamine Pharmacokinetics in HIV Positive Patients Seropositive for Toxoplasma Gondii

To determine the manner in which pyrimethamine is metabolized and excreted in patients currently receiving zidovudine (AZT). An important goal of this measurement is to establish the optimal dose of pyrimethamine necessary to prevent the development of toxoplasmosis in AIDS patients or delay the subsequent return of toxoplasmic encephalitis.

Encephalitis caused by Toxoplasma gondii has emerged as the most frequent cause of focal central nervous system infection in patients with AIDS. Untreated, the encephalitis is fatal. The best treatment for this disease has not been determined. Presently it is standard practice to administer a combination of pyrimethamine and sulfadiazine. Little is known about the pharmacokinetics of pyrimethamine in patients with AIDS receiving AZT. Furthermore, there are reports that patients already exposed to toxoplasmosis may not have uniform absorption of pyrimethamine.

Study Overview

Detailed Description

Encephalitis caused by Toxoplasma gondii has emerged as the most frequent cause of focal central nervous system infection in patients with AIDS. Untreated, the encephalitis is fatal. The best treatment for this disease has not been determined. Presently it is standard practice to administer a combination of pyrimethamine and sulfadiazine. Little is known about the pharmacokinetics of pyrimethamine in patients with AIDS receiving AZT. Furthermore, there are reports that patients already exposed to toxoplasmosis may not have uniform absorption of pyrimethamine.

Patients receive the study treatment for a total of 22 days. Patients are given an initial dose of pyrimethamine followed by a lower dose given as a single oral daily dose for 21 days. Patients continue to receive AZT at the dose prescribed prior to enrollment in the study. Patients receive leucovorin calcium once a day. Neither the leucovorin calcium nor the AZT are provided through the study.

Study Type

Interventional

Enrollment

26

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • New York
      • New York, New York, United States, 10021
        • Memorial Sloan-Kettering Cancer Ctr.
    • North Carolina
      • Chapel Hill, North Carolina, United States, 27599
        • Unc Aids Crs

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria

Concurrent Medication:

Allowed:

  • Aerosolized pentamidine for Pneumocystis carinii pneumonia prophylaxis.
  • Isoniazid not initiated during study period.
  • Methadone maintenance.

Required:

  • Stable prescribed dose of zidovudine (AZT) of at least 500 mg/day.

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions or symptoms are excluded:

  • Prior history of toxoplasmic encephalitis.
  • Unable to take oral medication reliably or have a malabsorption syndrome (i.e., 3 or more loose stools/day for at least 4 weeks associated with an unintentional weight loss of = or > 10 percent of body weight).
  • History of sensitivity to the study medications.

Concurrent Medication:

Excluded:

  • Maintenance therapy for opportunistic infections with macrolides or sulfonamides, immunomodulators, rifampin, amphotericin, dapsone, ganciclovir, antifolates, probenecid, benzodiazepines, nephrotoxins, and experimental cytotoxic chemotherapy.
  • Medications such as aspirin, benzodiazepines, cimetidine, indomethacin, morphine, and sulfonamides should be avoided.

Concurrent Treatment:

Excluded:

  • Lymphocyte replacement.

Patients with the following are excluded:

  • Any medical or social condition that, in the opinion of the investigator, would adversely affect either participation or compliance in the study.
  • Diagnosis of AIDS and febrile and have evidence of another serious opportunistic infection or central nervous system impairment.

Prior Medication:

Excluded:

  • Maintenance therapy for opportunistic infections with macrolides or sulfonamides, immunomodulators, rifampin, amphotericin, dapsone, ganciclovir, antifolates, probenecid, benzodiazepines, nephrotoxins, and experimental cytotoxic chemotherapy within past 14 days.

Prior Treatment:

Excluded:

  • Lymphocyte replacement within past 14 days.

Patients have the following symptoms and conditions:

  • Laboratory evidence of HIV infection.
  • Serological evidence of exposure to Toxoplasma gondii, but no clinical evidence of active toxoplasmic infection.
  • Able to understand and sign a written informed consent.
  • Either homosexual male or intravenous drug user.

Required:

  • Stable prescribed dose of zidovudine (AZT) of at least 500 mg/day for 4 weeks.

Intravenous drug abuse.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Masking: None (Open Label)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Collaborators

Investigators

  • Study Chair: B Luft

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Completion (Actual)

March 1, 1995

Study Registration Dates

First Submitted

November 2, 1999

First Submitted That Met QC Criteria

August 30, 2001

First Posted (Estimate)

August 31, 2001

Study Record Updates

Last Update Posted (Actual)

November 4, 2021

Last Update Submitted That Met QC Criteria

October 28, 2021

Last Verified

October 1, 2021

More Information

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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