Does PrEP interact with food or other meds?
Oral PrEP is just as effective whether it is taken with or without food.
However, TD is absorbed more quickly if it is taken with food and so this could be used if you are late with your dose.
Oral PrEP only interacts with a few other medicines, covered below.
But if you routinely take other prescribed or over-the-counter meds, please tell your doctor (including your GP) that you are taking PrEP. Any pharmacist can also check for drug interactions if you don’t want your GP to know.
Tenofovir (TD) should also be used with caution if you regularly take other drugs that affect the kidneys. These include some non-steroidal anti-inflammatory drugs (NSAIDs), especially diclofenac, ibuprofen and naproxen.
Routinely taking these drugs with PrEP can cause kidney problems. Avoid these meds when taking PrEP and please let your doctor know if you regularly need to take them.
TAF can interact with TB meds, anti-epileptics, St John’s Wort and others. These interactions are not a problem with TD.
It is easy to check for interactions here:
hiv-druginteractions.org/checker
This factsheet covers drug interactions between about 85 other medications where there are cautions about long-term use with oral PrEP.
www.hiv-druginteractions.org/prescribing_resources/hiv-guidance-prep
For trans and non-binary people
Oral PrEP is very safe for trans and non-binary people taking hormone therapy.
Info on interactions between PrEP and other meds, including hormone treatment, is on this site from Liverpool University:
hiv-druginteractions.org/checker
Injectable PrEP
Injectable PrEP can also be taken with or without food.
There are no interactions with oral contraceptives or with gender affirming hormones that need a dose adjustment.
These drugs can interact with different other meds though.
Because these drugs stay in your body for such a long time, interactions can continue for a long time after the last injection. Please see the full prescribing information for details of these and other interactions.
Please tell your doctor or pharmacist about any other drugs or supplements that you take. Drug interactions can also be checked using the online checker at Liverpool University HIV Interaction website:
https://www.hiv-druginteractions.org/checker
CAB-LA can interact with:
- Carbamazepine, oxcarbazepine, phenobarbital, phenytoin (medicines for epilepsy).
- Rifabutin, rifampicin, rifapentine (antibiotics).
- Systemic dexamethasone (a steroid anti-inflammatory and immunosuppressant medicine), except when used as a single dose treatment.
- St John’s wort (a herbal antidepressant medicine).
LEN interactions:
The following should NOT be taken with LEN as they reduce LEN levels:
- Some HIV meds: efavirenz, etravirine, nevirapine, atazanavir/cobicistat, and tipranavir/ritonavir.
- Some TB meds: rifampicin, rifabutin.
- Some anticonvulsants: carbamazepine, phenytoin, oxcarbazepine and phenobarbital.
- Some herbal supplements: St. John’s wort.
The following drugs can be increased by LEN. They can sometimes be used at lower doses.
- Some PDE-5 erectile drugs: sildenafil (Viagra), taladafil, vardenafil.
- Ergot derivatives: dihydroergotamine and ergotamine.
- Some corticosteroids: dexamethasone hydrocortisone/cortisone.
- Some other drugs: dioxin, midazolam, triazolam, lovastatin and simvastatin.
Last updated: 1 November 2025.