Is Calcium Safe with Tenofovir?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Take calcium supplements at least 2 hours before or 4 hours after Tenofovir to minimize potential impact on drug absorption and renal handling.
Why this interaction occurs
High-dose calcium supplementation may affect renal tubular function. Tenofovir relies on renal tubular secretion, and calcium can influence the transporters (OAT1/OAT3) involved in Tenofovir elimination, potentially altering drug levels or increasing nephrotoxicity risk.
Evidence
Evidence level: moderate.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 39,320 reports mentioning Tenofovir. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Tenofovir + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Calcium interactions → · All Tenofovir interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.