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Influence of concurrent oral calcium carbonate supplementation on steady-state pharmacokinetics of once daily oral raltegravir in persons with HIV: a protocol for a prospective open-label non-randomised study in Canada

Teixeira Nunes Porto LL, Doyle MA, Zhang G, Tremblay N, Yazji B, Kanji S, Cameron DW

BMJ open, 2025

12 participants

Abstract

Introduction: Raltegravir is a potent HIV-integrase strand transfer inhibitor (INSTI). Despite its strong activity against HIV-1 strains resistant to other antiretroviral drug classes, it is usually used in combination with other antiretroviral drugs due to the empirical requirement for anti-HIV drug combinations to ensure effective anti-retroviral therapy (ART). As an early-arriving INSTI, raltegravir is clinically familiar for its safety, tolerability and treatment effectiveness. High-dose calcium carbonate formulated as an antacid (as opposed to a supplement formulation) taken orally together with raltegravir is known to reduce systemic raltegravir exposure due to chelation and reduced absorption. This study aims to assess the effect of daily calcium carbonate antacid as TUMS Ultra Strength (US) administration in lower doses, as currently used for oral calcium supplementation, on the steady-state pharmacokinetics (PKs) of once-daily oral raltegravir.

Methods and analysis: This is an open-label, three-treatment series in three periods in a single group, fixed-sequence PK study in 12 healthy adult volunteers with HIV on ART. Subjects will take 1200 mg of raltegravir single QD oral dose alone for 7 days (period one), then raltegravir 1200 mg with calcium carbonate 500 mg from day 8 to day 14 (period two) and raltegravir 1200 mg with calcium carbonate 1000 mg from day 15 to day 22 (period three). We will conduct serial PK sampling from observed dosing on days 7, 14 and 21,…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 12 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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