These drugs may be available either as single agents or as part of a fixed-dose combination tablet.

Names: Abacavir, ABC, Ziagen

Approved dosage: Take 600mg daily, either as one 300mg yellow tablet twice daily or two 300mg tablets once a day. Usually dispensed in a combined formulation with lamivudine in a number of generic brands or a pill combined with dolutegravir and lamivudine, called Triumeq.

Tips on taking it: Take 600mg (two tablets) a day with or without food.

Common or very common side-effects: Nausea, vomiting, diarrhoea, abdominal pain, loss of appetite, fever, headache, tiredness.

Rare side-effects: Allergic (hypersensitivity) reaction, lactic acidosis (too much lactic acid in the blood). Some, but not all, cohort studies have linked abacavir with an increased risk of heart attack. For this reason, abacavir is not recommended if you have other risk factors for heart disease. Your doctor should discuss this with you.

Important warning: Abacavir can cause a serious allergic (hypersensitivity) reaction in people with one particular gene. Before starting treatment with abacavir or any abacavir-containing regimen you should have an HLA-B*5701 test to see if you have this gene. If the test is positive you must not take abacavir. If the test is negative, it is highly unlikely that an allergic reaction will occur, but contact your HIV clinic immediately (or A&E if out of hours) if you begin to feel unwell after starting the drug.

In the box with the drug there is an ‘alert card’, which you should carry with you for the first six weeks of taking abacavir. The particular side-effects you should look out for during this time are:

Any skin rash OR

If you get one or more symptoms from at least TWO of the following groups:

• fever
• shortness of breath, sore throat or cough
• nausea or vomiting, or diarrhoea or abdominal pain
• severe tiredness or achiness or generally feeling ill.

You should never retry abacavir, or take Triumeq or Kivexa, or generic formulations containing abacavir, if it has been stopped due to hypersensitivity with related side-effects. You should also never take any combination containing abacavir. These issues should be discussed with your doctor.

Children: Abacavir can be taken by children weighing 14kg or more. Tablets will be split for children weighing 14-20kg. A liquid formulation is also available for children and people who have swallowing difficulties.

Key drug interactions: Care should be taken when abacavir is taken with ribavirin, used to treat hepatitis C. Phenytoin, used to treat epilepsy, may also interact with abacavir.

Names: Emtricitabine, FTC, Emtriva

Approved dosage: Take one capsule once a day. Emtricitabine is also available in the following combination tablets:

• Truvada – combination tablet with tenofovir disoproxil
• Descovy – combination tablet with tenofovir alafenamide
• Atripla – combination tablet with tenofovir disoproxil and efavirenz
• Eviplera – combination tablet with tenofovir disoproxil and rilpivirine
• Stribild – combination tablet with tenofovir disoproxil, elvitegravir and cobicistat
• Odefsey – combination tablet with tenofovir alafenamide and rilpivirine
• Genvoya – combination tablet with tenofovir alafenamide, elvitegravir and cobicistat.

Tips on taking it: Take one capsule once daily. Can be taken with or without food.

Common or very common side-effects: Nausea, diarrhoea, vomiting, indigestion, headache, dizziness, weakness, fatigue, raised liver enzyme, amylase or creatine kinase levels, raised blood sugar and triglyceride levels, rash, itching, skin darkening, insomnia, abnormal dreams.

Rare side-effects: Lactic acidosis (too much lactic acid in the blood), liver damage.

Children: Approved for use by children aged 4 months and over.

Key drug interactions: Emtricitabine should not be used with the anti-HIV drug lamivudine.

Names: Lamivudine, 3TC, Epivir

Approved dosage: Take 300mg daily, as one 150mg tablet twice a day, or two 150mg tablets once a day, or one 300mg tablet once a day. Lamivudine is available as a generic drug, so its appearance will depend on which type your clinic dispenses. More often dispensed as a generic in a combination tablet with zidovudine or abacavir, or with abacavir and dolutegravir (Triumeq).

Tips on taking it: Take either once or twice daily with or without food.

Common or very common side-effects: Nausea, vomiting, diarrhoea, headache, general feeling of being unwell, cough, runny nose, abdominal pain, hair loss, fever, insomnia, rash, tiredness, muscle and joint pain.

Rare side-effects: Lactic acidosis (too much lactic acid in the blood), liver damage.

Children: Approved for use in children. Liquid suspension available.

Key drug interactions: Lamivudine should not be used with the anti-HIV drug emtricitabine.

Names: Tenofovir disoproxil 245mg, TDF, Viread, tenofovir alafenamide 10mg or 25mg, TAF

Approved dosage: Take one 245mg tablet daily. Tenofovir is available as a generic drug, so its appearance will depend on which type your clinic dispenses. The dose may be adjusted if kidney function is impaired. A newer formulation, tenofovir alafenamide (TAF), is available in some combination tablets. The two formulations of tenofovir are available in the following combination tablets:

• Truvada – combination tablet with tenofovir disoproxil and emtricitabine
• Descovy – combination tablet with tenofovir alafenamide and emtricitabine
• Atripla – combination tablet with tenofovir disoproxil, emtricitabine and efavirenz
• Eviplera – combination tablet with tenofovir disoproxil, emtricitabine and rilpivirine
• Stribild – combination tablet with tenofovir disoproxil, emtricitabine, elvitegravir and cobicistat
• Odefsey – combination tablet with tenofovir alafenamide, emtricitabine and rilpivirine
• Genvoya – combination tablet with tenofovir alafenamide, emtricitabine, elvitegravir and cobicistat.

Tips on taking it: Take with food, to increase absorption. However, it is generally accepted that tenofovir can be taken with or without food.

Common side-effects: Nausea, vomiting, diarrhoea, flatulence, dizziness, low blood phosphate levels, raised liver enzymes, weakness, rash, headache, abdominal pains, and bloating.

Rare side-effects: Kidney problems, bone thinning.

Children: Viread is approved for use in children aged 12 years and over. Reduced strength tablets are available for 6-12 year olds and granules for 2-12 year olds.

Key drug interactions: Taking tenofovir and atazanavir together decreases the concentration of atazanavir, so it should only be used if boosted with ritonavir. Protease inhibitors also increase concentrations of tenofovir, so if taken together your healthcare team should monitor you carefully for side-effects.

The antibiotics used to treat tuberculosis (TB), rifampicin and rifabutin, may reduce levels of tenofovir alafenamide; so may some anticonvulsants including phenytoin and phenobarbital.

It is important your doctor knows about any other drugs you are taking in case they increase your risk of kidney problems. This includes creatine supplements used to increase exercise performance, as they can interfere with the results of kidney function blood tests. Make sure you tell your doctor if you are taking creatine.

Names: Zidovudine, AZT, Retrovir

Approved dosage: Zidovudine is available as a generic drug, so its appearance will depend on which type your clinic dispenses.

The approved dose is one 250mg capsule taken twice a day. A 100mg capsule is available for dose variations. Also available as a generic in a combined tablet with lamivudine.

Zidovudine is no longer recommended in the BHIVA guidelines for people starting treatment for the first time, but it is still sometimes used in specific circumstances, such as during pregnancy and in new-born babies, or for people with resistance to other drugs.

Tips on taking it: Can be taken with or without food, but taking the dose with food reduces nausea.

Common side-effects: Nausea, vomiting, diarrhoea, generally feeling unwell, stomach pains, fatigue, headache, dizziness, weakness, muscle pain, loss of appetite.

Rare side-effects: Blood disorders, lipodystrophy, lactic acidosis, liver problems, pancreatitis.

Children: Approved for use in children. Liquid formulation available.

Key drug interactions: Close monitoring or dose adjustment is needed if zidovudine is taken with the antibiotic clarithromycin or phenytoin, a drug used to treat epilepsy. Several other types of drugs, when taken with zidovudine, can cause an increase in side-effects, so it is important to talk to your doctor about any other drugs you are taking. These include, but are not limited to, methadone and drugs to treat infections, cancer and malaria.

This combination is available as a generic or as a branded tablet. The branded version is called Kivexa. This drug combines lamivudine and abacavir. The dosage is one tablet (600mg abacavir and 300mg lamivudine) once a day.  

Tips on taking it: Take one tablet once a day, with or without food.

Common or very common side-effects: Headache, abdominal pain, hair loss, insomnia, tiredness, loss of appetite, runny nose and joint pain.

Important warning: Abacavir can cause a serious allergic (hypersensitivity) reaction. This is associated with the presence of a particular gene. Before starting treatment with an abacavir-containing regimen you should have a test to see if you have the HLA-B*5701 gene. If the test is positive you must not takeabacavir/lamivudine. If the test is negative, it is unlikely that an allergic reaction will occur, but you must contact your HIV clinic immediately (or A&E if out of hours) if you begin to feel unwell after starting the drug.

In the box with the drug there is an ‘alert card’, which you should carry with you for the first six weeks of taking abacavir/lamivudine. The particular side-effects you should look out for during this time are:

Any skin rash OR

If you get one or more symptoms from at least TWO of the following groups:

• fever
• shortness of breath, sore throat or cough
• nausea or vomiting, or diarrhoea or abdominal pain
• severe tiredness or achiness or generally feeling ill.

Children: Abacavir/lamivudine (600/300mg) can be taken by children weighing 25kg or more.

See the entries on lamivudine and abacavir above for more detail.

Emtricitabine and tenofovir disoproxil are combined in this pill. The dose is one tablet (200mg emtricitabine and 245mg tenofovir disoproxil) taken once a day. Some clinics may dispense a generic version of this combination pill.

Tips on taking it: Take one tablet once a day, preferably with food, although you can take Truvada on an empty stomach.

Common or very common side-effects: Nausea, vomiting, diarrhoea, insomnia, abnormal dreams, headache, dizziness, allergic (hypersensitivity) reaction, rash, itching, weakness, abdominal pain, fatigue, bloating, flatulence, heartburn, raised blood sugar, pancreatic enzyme and triglyceride levels, raised liver enzyme or creatine kinase levels, low blood phosphate levels, skin darkening, low white blood cell count.

Rare side-effects: Kidney failure, lactic acidosis (too much lactic acid in the blood), bone thinning, pancreatitis.

Children: Truvada can be taken by children aged 12 years and over, weighing 35kg or more.

See the entries for emtricitabine and tenofovir above for more detail.

Emtricitabine and a new formulation of tenofovir known as tenofovir alafenamide are combined in this pill. The dose is one grey tablet (200mg emtricitabine and 10mg of tenofovir alafenamide) or one blue tablet (200mg emtricitabine and 25mg of tenofovir alafenamide) taken once a day. Descovy is one of the NRTI combinations recommended in the BHIVA guidelines.

Tips on taking it: Take one tablet once a day with or without food. The pill containing 10mg of tenofovir alafenamide should only be taken if combined with the boosters ritonavir or cobicistat. The pill containing 25mg of tenofovir alafenamide should be taken with all other third agents, e.g. etravirine, raltegravir, efavirenz, dolutegravir.

Common or very common side-effects: Headache, dizziness, abnormal dreams, nausea, vomiting, diarrhoea, abdominal pain, flatulence, indigestion, rash, tiredness.

Rare side-effects: Anaemia, swelling of the skin, face, lips, tongue or throat.

Children: Descovy can be taken by children aged 12 years and over, weighing 35kg or more.

See the entries on emtricitabine and tenofovir above for more detail.

A combination tablet containing lamivudine and zidovudine is available as a generic product. The dosage is one tablet (150mg lamivudine and 300mg zidovudine) twice a day. Because it is a generic drug, its appearance will depend on which type your clinic dispenses.

Zidovudine is no longer recommended in the BHIVA guidelines for people starting HIV treatment (see section on zidovudine). Lamivudine/zidovudine may be prescribed for pregnant women who start treatment at the time of delivery and for new-born babies.

Tips on taking it: Take one tablet twice a day with or without food.

Common or very common side-effects: Nausea, vomiting, diarrhoea, tiredness, headache, dizziness, weakness, muscle pain, loss of appetite, fever, abdominal pain, hair loss, insomnia, rash, cough, runny nose, joint or muscle pain, fat loss, anaemia, low white blood cell count, raised liver enzymes.

Rare side-effects: Liver damage, severe anaemia, lactic acidosis (too much lactic acid in the blood).

Children: Lamivudine/zidovudine can be taken by children weighing 14kg or more. Tablets will be split for children weighing 14-30kg.

See the entries on zidovudine and lamivudine above for more detail.