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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 is not medical advice and 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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