Prescription ·Strong evidence ·Reviewed May 2026
Tenofovir disoproxil is an oral prodrug of tenofovir, a nucleotide analog reverse-transcriptase inhibitor used to treat HIV-1 infection only in combination with other antiretrovirals and to treat chronic hepatitis B. It is used as a single agent for hepatitis B and as a component of fixed-dose HIV treatment and PrEP combinations. Long-term use is associated with declines in bone mineral density and renal tubular effects that can lower serum phosphate.
The bottom line
Evidence rating strong. Most-documented uses: treatment of hiv-1 infection in combination with other antiretroviral agents, treatment of chronic hepatitis b in adults and adolescents, component of hiv pre-exposure prophylaxis (prep) regimens. 2 sources indexed (2010–2019), with 6 interaction records on file.
Core mechanism
Tenofovir disoproxil is rapidly hydrolyzed to tenofovir, which is then phosphorylated by cellular kinases to its active metabolite tenofovir diphosphate. This active form is an analog of deoxyadenosine 5'-triphosphate and inhibits HIV-1 reverse transcriptase and hepatitis B virus polymerase by competing with the natural substrate and, after incorporation into the growing viral DNA chain, causing chain termination because it lacks the 3'-hydroxyl group needed for further nucleotide addition. The result is suppression of viral replication. Renal proximal tubular accumulation of tenofovir can impair tubular reabsorption, contributing to phosphate wasting, reduced active vitamin D metabolism, and secondary effects on calcium and bone metabolism.1,2
Can be taken with or without food; a high-fat meal increases oral bioavailability of tenofovir but the drug may be administered regardless of meals. Consistent daily dosing matters more than meal timing.2
Nutrients this medication can lower over time, and what to replace.
Tenofovir-associated proximal renal tubulopathy can cause urinary phosphate wasting and hypophosphatemia.
Tenofovir disoproxil fumarate accumulates in proximal renal tubular cells and impairs mitochondrial function and sodium-phosphate cotransporter activity, causing proximal tubular dysfunction (Fanconi-like syndrome) with renal phosphate wasting and consequent hypophosphatemia.
Proximal tubular injury reduces renal 1-alpha-hydroxylase activity and impairs conversion of 25-hydroxyvitamin D to active 1,25-dihydroxyvitamin D, while associated secondary hyperparathyroidism further dysregulates vitamin D metabolism, contributing to lower active vitamin D status.
Renal phosphate wasting, reduced active vitamin D, and secondary hyperparathyroidism increase bone turnover and urinary calcium losses; proximal tubulopathy can also cause hypercalciuria, collectively promoting negative calcium balance and reduced bone mineral density.
Tenofovir disoproxil can reduce bone mineral density and may contribute to phosphate wasting; correcting vitamin D deficiency is part of bone-risk management.
Recommendation: Check 25-hydroxyvitamin D and bone risk when therapy is long term or risk factors are present; supplement to target if deficient.
Adequate calcium intake is relevant because tenofovir disoproxil can reduce bone mineral density.
Recommendation: Use dietary calcium or supplements only to meet total intake goals; avoid excess in kidney stone or kidney disease risk.
Creatine can raise measured serum creatinine and complicate renal assessment for Tenofovir Disoproxil, which depends on kidney function for dosing or toxicity monitoring.
Recommendation: Tell the prescriber about creatine use and avoid creatine loading during acute illness, kidney injury, or therapy requiring close renal dosing.
Tenofovir disoproxil can cause proximal renal tubular dysfunction (a Fanconi-like syndrome) that produces urinary wasting of phosphate, potassium, and magnesium in susceptible patients. Low serum magnesium may develop or worsen during long-term therapy, and unrecognized hypomagnesemia can in turn make potassium and calcium repletion difficult. Magnesium glycinate is a reasonable, well-tolerated form for correcting documented deficiency, but supplementation should be guided by lab values rather than used to mask ongoing tubular injury.
Recommendation: If a patient on long-term TDF develops fatigue, muscle cramps, or electrolyte abnormalities, check serum magnesium, potassium, phosphate, and renal tubular markers. Replete magnesium when deficiency is confirmed; magnesium glycinate is gentler on the gut than oxide. Persistent or worsening electrolyte wasting should prompt evaluation for tenofovir nephrotoxicity and possible switch to tenofovir alafenamide. Avoid high-dose magnesium in renal impairment without monitoring.
Tenofovir disoproxil-induced proximal renal tubular dysfunction can cause urinary potassium wasting and hypokalemia, sometimes with metabolic acidosis, in patients developing a Fanconi-like syndrome. While some patients may require potassium repletion, others (particularly those with declining renal function from tenofovir nephrotoxicity) can be at risk of hyperkalemia, so unsupervised potassium supplementation is hazardous. Falling or abnormal potassium during TDF therapy should be interpreted in the context of kidney function rather than treated empirically.
Recommendation: Do not take potassium supplements while on TDF without monitoring serum potassium and renal function. Treat documented hypokalemia under clinical supervision and investigate for tubular toxicity. In patients with reduced eGFR or those also on ACE inhibitors, ARBs, or potassium-sparing diuretics, potassium supplementation can precipitate dangerous hyperkalemia. Persistent electrolyte disturbance should prompt reassessment of the tenofovir formulation.
Tenofovir disoproxil is eliminated renally and can cause nephrotoxicity, including a Fanconi-like proximal tubulopathy, in susceptible patients. Chronic high-dose vitamin C (typically several grams daily) increases urinary oxalate excretion and is an independent risk factor for kidney stones and can add oxidative/oxalate burden to the kidney. In a patient already at some risk of tenofovir-related renal injury, habitual megadose vitamin C is an avoidable additional renal stressor. Ordinary dietary or low supplemental doses of vitamin C are not a meaningful concern.
Recommendation: Avoid chronic high-dose vitamin C (gram-level daily supplements) while on TDF, especially with any history of kidney stones, reduced eGFR, or signs of tubular dysfunction. Standard dietary intake and typical multivitamin amounts are fine. Maintain good hydration and keep up routine renal monitoring (creatinine, eGFR, urinalysis for proteinuria and glucosuria) during tenofovir therapy.
Numbered references. Citations throughout the page link here.
Tenofovir disoproxil is associated with greater loss of bone mineral density and a modest increased risk of renal proximal tubular dysfunction compared with comparator regimens.
Standard adult dosing is 300 mg orally once daily; long-term use is associated with decreases in bone mineral density and renal adverse effects requiring monitoring.
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