What is lopinavir/ritonavir?

Lopinavir/ritonavir is a medication used to treat HIV. It is a combination of an antiretroviral drug called lopinavir and a low-dose of another antiretroviral drug called ritonavir, which is used to boost the effect of lopinavir. These two drugs are combined in one pill, to be taken along with other antiretroviral drugs to make up a treatment combination.

The usual dose of lopinavir/ritonavir for adults is 800mg lopinavir and 200mg ritonavir every day. This dose can be made up of two yellow tablets containing 200mg lopinavir and 50mg ritonavir taken twice a day. Or, four of these tablets taken once a day. Lopinavir/ritonavir is sometimes marketed under the name Kaletra, but generic versions are also available.

How does lopinavir/ritonavir work?

Lopinavir/ritonavir combines two drugs in one pill. Both drugs are from a class of drugs known as protease inhibitors. The drug ritonavir increases or ‘boosts’ the level of lopinavir. Your doctor will prescribe lopinavir/ritonavir as part of your HIV treatment, along with antiretrovirals from another class of drugs. It is important to take all the drugs as prescribed, every day. Each drug class works against HIV in a different way.

The aim of HIV treatment is to reduce the level of HIV in your body (viral load). Ideally, your viral load should become so low that it is undetectable – usually less than 50 copies of virus per ml of blood. Taking HIV treatment and having an undetectable viral load protects your immune system and stops HIV being passed on to someone else during sex.

How do I take lopinavir/ritonavir?

You can take lopinavir/ritonavir with or without food but taking with food can reduce potential irritation of the stomach.

It is important that you swallow the tablets whole and don’t break, crush or chew them.

HIV treatment works best if you take it every day. When would be a good time for you to plan to take your treatment?

If you forget to take a dose of lopinavir/ritonavir, take it as soon as you remember.

If you are taking lopinavir/ritonavir twice a day, if it has been more than 6 hours since your dose was due, then don’t take a double dose, just skip the dose you’ve forgotten and carry on.

If you are taking lopinavir/ritonavir once a day, if it has been more than 12 hours since your dose was due, then don’t take a double dose, just skip the dose you’ve forgotten and carry on.


antiretroviral (ARV)

A substance that acts against retroviruses such as HIV. There are several classes of antiretrovirals, which are defined by what step of viral replication they target: nucleoside reverse transcriptase inhibitors; non-nucleoside reverse transcriptase inhibitors; protease inhibitors; entry inhibitors; integrase (strand transfer) inhibitors.

viral load

Measurement of the amount of virus in a blood sample, reported as number of HIV RNA copies per milliliter of blood plasma. The VL is an important indicator of HIV progression and of how well treatment is working. 


undetectable viral load

A level of viral load that is too low to be picked up by the particular viral load test being used or below an agreed threshold (such as 50 copies/ml or 200 copies/ml). An undetectable viral load is the first goal of antiretroviral therapy.

high blood pressure

Raised blood pressure.


Raised blood pressure.

If you regularly forget to take your treatment, or you aren’t taking it for another reason, it’s important to talk to your doctor about this.

What are the possible side-effects of lopinavir/ritonavir?

All drugs have possible side-effects. It’s a good idea to talk to your doctor about possible side-effects before you start taking a drug. If you experience something that might be a side-effect, talk to your doctor about what can be done. A full list of side-effects, including less common side-effects, should be included in the leaflet that comes in the packaging with lopinavir/ritonavir.

We generally divide side-effects into two types:

Common – a side-effect that occurs in at least one in a hundred people (more than 1%) who take this drug.

Rare – a side-effect that occurs in fewer than one in a hundred people (less than 1%) who take this drug.

Common side-effects of lopinavir/ritonavir include (most common in bold):

Diarrhoea, nausea, sinus or throat infections, pancreatitis, vomiting, abdominal pain, bloating, flatulence, heartburn and indigestion, loss of appetite, raised lipids or blood sugar, diabetes, high blood pressure, rash, itching, skin infections, dizziness, tiredness, difficulty in sleeping, anxiety, weakness, headache, haemorrhoids, raised liver enzymes, allergic reaction including swelling, infections in the respiratory tract, cough, sore throat, runny nose, erectile dysfunction, menstrual disorders, peripheral nerve damage, muscle pain.

Does lopinavir/ritonavir interact with other drugs?

It’s important that your doctor and pharmacist know about any other drugs you are taking. That includes medicine prescribed by another doctor, drugs you have bought from a high-street chemist, herbal and alternative treatments, and recreational drugs.

Some medicines should not be taken together because if they are this can cause serious side-effects, or it can stop one or both of the drugs from working. Other drug interactions are less dangerous but still need to be taken seriously. If levels of one drug are affected, you may need to change the dose you take.

A list of drugs known to have interactions with lopinavir/ritonavir should be included in the leaflet that comes in the packaging with lopinavir/ritonavir. Tell your doctor if you are taking any of these drugs, and other drugs that are not on the list.

You should not take lopinavir/ritonavir with any of the following drugs:

  • alfuzosin
  • amiodarone
  • astemizole
  • avanafil
  • cisapride
  • colchicine
  • dihydroergotamine
  • dronedarone
  • elbasvir/grazoprevir
  • ergonovine
  • ergotamine
  • fusidic acid
  • lovastatin
  • lurasidone
  • ombitasvir/paritaprevir/ritonavir
  • methylergonovine
  • midazolam taken orally
  • pimozide
  • quetiapine
  • ranolazine
  • sildenafil (for hypertension)
  • simvastatin
  • St John's wort
  • terfenadine
  • triazolam
  • vardenafil.

Sildenafil is a drug used to treat pulmonary arterial hypertension (high blood pressure in the lungs). You should not take sildenafil with lopinavir/ritonavir if sildenafil was prescribed for this reason. Sildenafil (Viagra) is also used to treat erectile dysfunction (impotence). If you are using sildenafil for erectile dysfunction, tell your doctor before you start treatment with lopinavir/ritonavir.

Can I take lopinavir/ritonavir in pregnancy?

If you are considering having a baby, or think you might be pregnant, talk to your doctor as soon as possible about which combination of anti-HIV medications would be right for you. It is important to take antiretroviral treatment during pregnancy to prevent passing HIV from mother to baby.

The British HIV Association (BHIVA) recommends that women who are already taking anti-HIV medications and become pregnant can usually continue to take the same medication throughout their pregnancy. However, they advise against taking lopinavir/ritonavir in combination with tenofovir and emtricitabine during pregnancy.

Can children take lopinavir/ritonavir?

A lopinavir/ritonavir tablet containing 100mg of lopinavir and 25mg of ritonavir is available for use by children who can swallow a tablet. A liquid formulation is also available.

Talking to your doctor

If you have any concerns about your treatment or other aspects of your health, it’s important to talk to your doctor about them.

For example, if you have a symptom or side-effect or if you are having problems taking your treatment every day, it’s important that your doctor knows about this. If you are taking any other medication or recreational drugs, or if you have another medical condition, this is also important for your doctor to know about.

Building a relationship with a doctor may take time. You may feel very comfortable talking to your doctor, but some people find it more difficult, particularly when talking about sex, mental health, or symptoms they find embarrassing. It’s also easy to forget things you wanted to talk about.

Preparing for an appointment can be very helpful. Take some time to think about what you are going to say. You might find it helpful to talk to someone else first, or to make some notes and bring them to your appointment. 

For detailed information on this drug, visit the lopinavir/ritonavir pages in the A-Z of antiretroviral medications.

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