Tenofovir is an antiretroviral medication used to treat and prevent HIV infection. It belongs to the nucleotide analogue reverse transcriptase inhibitor (NtRTI) class and is commonly combined with other antiretrovirals for first-line treatment.
Also known as: Viread, TDF, tenofovir disoproxil fumarate
Tenofovir and metformine are both renally eliminated. Coadministration may increase the risk of nephrotoxic effects and lactic acidosis. Monitor renal function.
Tenofovir and metformine are both essentially eliminated renally — tenofovir by glomerular filtration and tubular secretion, metformine by tubular secretion via OCT2. Coadministration may compete for tubular secretion, potentially elevating levels of both. The main risk is additive nephrotoxicity: tenofovir may cause proximal tubular nephrotoxicity (Fanconi syndrome), while metformine requires adequate renal function to prevent accumulation and lactic acidosis. Recommendation: assess GFR before initiation and monitor periodically (creatinine, electrolytes, proteinuria). Adjust metformine dose if GFR <30 mL/min. Consider alternative to tenofovir (entecavir) if renal deterioration occurs.
Tenofovir + metformine: both renally eliminated. Risk of additive toxicity and lactic acidosis. Monitor renal function.
Both drugs compete for renal tubular secretion. Tenofovir may reduce metformine clearance, increasing its levels. The risk of lactic acidosis increases in patients with renal impairment.
Serum creatinine, GFR, lactic acid, symptoms of lactic acidosis (nausea, vomiting, abdominal pain, confusion).
Lactic acidosis (rare but potentially fatal). Acute renal failure.
Monitor renal function (creatinine, GFR) before and during treatment. Adjust metformine dose if GFR <30 mL/min. Consider alternative to tenofovir (e.g. entecavir for hepatitis B).
DailyMed/FDA (NIH/NLM) — approved Tenofovir (Viread) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33fd6418-fbdc-42ca-a50d-ce2a476a5418 ; approved Metformine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=7b43f66c-8e1a-4a6b-b582-c1e5bb48d3df
Food slightly increases tenofovir absorption (25% vs fasting), but the effect is clinically insignificant.
Can be taken with or without food.
DailyMed/FDA (NIH/NLM) — approved Tenofovir (Viread) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33fd6418-fbdc-42ca-a50d-ce2a476a5418
Tenofovir is nephrotoxic and renally eliminated. Renal impairment increases the risk of toxicity.
Assess GFR before initiation. Contraindicated if GFR <30 mL/min. Adjust dosing interval according to GFR.
DailyMed/FDA (NIH/NLM) — approved Tenofovir (Viread) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33fd6418-fbdc-42ca-a50d-ce2a476a5418
Abrupt discontinuation may cause severe hepatitis B exacerbation. Monitor HBV viral load.
DO NOT abruptly discontinue in patients co-infected with hepatitis B. Consider concomitant anti-HBV therapy.
DailyMed/FDA (NIH/NLM) — approved Tenofovir (Viread) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33fd6418-fbdc-42ca-a50d-ce2a476a5418
Limited human data. Animal studies did not demonstrate teratogenicity. WHO recommends use during pregnancy when benefit outweighs risk.
Can be used in all trimesters when indicated for HIV treatment. Monitor renal function.
Excreted in breast milk. Artificial feeding is recommended for HIV-positive mothers to prevent vertical transmission.
Reliable contraceptive methods are recommended during treatment.
DailyMed/FDA (NIH/NLM) — approved Tenofovir (Viread) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33fd6418-fbdc-42ca-a50d-ce2a476a5418
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Tenofovir is an adenine nucleotide analogue that inhibits HIV-1 and HBV reverse transcriptase, competing with the natural substrate (deoxyadenosine triphosphate).
Intracellularly phosphorylated to the active diphosphate (tenofovir diphosphate), which incorporates into viral DNA and causes chain termination (absence of the 3-OH group). Also acts as a competitive inhibitor of reverse transcriptase.
Oral bioavailability: 25% (after tenofovir disoproxil administration). Food increases absorption (Tmax 0.58-4h). Plasma protein binding <1%.
Minimally metabolised — excreted essentially unchanged by the renal route (proximal tubular). Does not undergo significant hepatic metabolism. Low drug interaction potential (does not inhibit CYP).
12-17 hours (intracellular diphosphate: >60 hours). Renal elimination (crcl 51-130 mL/min: 99% excreted in urine).
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
