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Safety information · Internal patient-safety page

Emtricitabine/tenofovir safety summary

Emtricitabine/tenofovir disoproxil is the daily combination tablet used as HIV pre-exposure prophylaxis (PrEP). Taken consistently every day it is highly effective at preventing HIV, but it comes with a testing rhythm: an HIV test before starting and every 3 months, plus regular kidney checks. It does not protect against other sexually transmitted infections.

Emtricitabine/tenofovir

What it's used for

  • One tablet once a day, preferably with food.
  • Only start after a confirmed negative HIV test, and repeat the test every 3 months while on PrEP.
  • Protection depends on taking it every day; missed doses lower it substantially.
  • Keep using condoms: PrEP does not protect against other STIs or pregnancy.

Most common side effects

  • Nausea and diarrhoea.
  • Headache and dizziness.
  • Tiredness.
  • Trouble sleeping or unusual dreams.
  • Mild rash.
  • A small decrease in bone mineral density over time, one reason for medical follow-up.

Serious side effects: stop and seek care

  • Kidney problems: changes in how much you urinate, swelling of ankles or feet, unusual fatigue. Kidney function is monitored with blood tests for exactly this reason.
  • Lactic acidosis (very rare): deep rapid breathing, unusual muscle pain, severe exhaustion; needs urgent care.
  • Signs of a new HIV infection such as fever, sore throat or swollen glands after a possible exposure: get tested immediately; continuing PrEP with an undetected infection breeds resistance.
  • If you carry hepatitis B: stopping this medicine can trigger a severe flare of the hepatitis. Never stop without medical advice.

Who should not take it

  • Anyone who is HIV-positive or whose HIV status is unknown: PrEP alone is not an HIV treatment.
  • Allergy to emtricitabine, tenofovir or any tablet ingredient.
  • Significantly reduced kidney function.
  • Hepatitis-B status should be checked before starting, because of the stopping-flare risk.

Interactions to flag

  • Never combine with other medicines containing tenofovir, or with adefovir.
  • Medicines that strain the kidneys, such as long-term NSAIDs (ibuprofen, diclofenac) and aminoglycoside antibiotics, increase the risk of kidney damage.
  • Some hepatitis-C treatments (ledipasvir or velpatasvir with sofosbuvir) raise tenofovir levels: monitoring may be needed.
  • Didanosine: do not combine.

Message us in the app chat if you notice any of these

  • A possible HIV exposure while you had missed doses.
  • Fever, sore throat or swollen glands.
  • Changes in urination, or swelling in your legs or ankles.
  • You want to stop PrEP, especially if you have hepatitis B; stopping needs a plan, not just an empty box.
AEMPS CIMA: Emtricitabine/tenofovir 200 mg/245 mg

This page summarises information from the regulator-approved leaflet for reference only. It does not replace the full leaflet, linked on this page, it is not medical advice and it does not replace the assessment of an EU-licensed doctor. Your doctor will review your individual history, dose and interactions during your consultation.

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