Communicable Diseases Module: 22. Introduction to Antiretroviral Therapy

Study Session 22  Introduction to Antiretroviral Therapy

Introduction

In this study session you will learn about the main therapy used to treat people living with HIV (PLHIV), and its benefits and goals, so that you will be able to help patients get the full benefits of the treatment, and maintain their health for as long as possible. The treatment used for HIV-positive people is called antiretroviral therapy, which can be shortened to ART. It consists of giving drugs termed antiretrovirals (ARVs), which work by attacking the human immunodeficiency virus (HIV) itself.

For ART to be successful, you should be aware of two things. First, ARV drugs should be given in the correct way; that means using a combination of three ARVs which act on the virus differently. Secondly, ART should be given continuously as a lifelong treatment. In addition to improving the quality of life for patients, ART also has the benefits of reducing stigma and discrimination, and increasing the chances of PLHIV going to HIV/AIDS services to ask for help.

Even though you are not expected to prescribe ART for patients, you need to be familiar with the basic concepts and the most common adverse side-effects of the drugs. This information will help you to provide good care for PLHIV who are being treated with ARVs. Remember that drug treatments for chronic diseases require adherence, which means taking medications as instructed by the prescribing health professional. It is also important for you to trace ‘treatment defaulters’ (PLHIV who stop taking their medications), to reduce the consequences for the patient, and for public health at large.

Learning Outcomes for Study Session 22

When you have studied this session, you should be able to:

22.1  Define and use correctly all of the key words printed in bold. (SAQs 22.1 and 22.2)

22.2  Explain what antiretroviral therapy (ART) is, and its goals and benefits. (SAQs 22.1, 22.2 and 22.4)

22.3  Explain why three antiretroviral (ARV) drugs are needed for effective ART and how they can be combined. (SAQ 22.3)

22.4  State the four first-line ARV regimens, their common side-effects, and describe what you should do if these side-effects occur. (SAQs 22.3 22.5)

22.1  The difference between treatment and cure in HIV/AIDS

Knowing the difference between treatment and cure is quite important in providing care to patients with chronic illnesses like HIV/AIDS. Treatment is the application of a medicine or a remedy to relieve symptoms and/or signs of an illness; in the context of a communicable disease like HIV/AIDS, it doesn’t necessarily mean getting rid of the infectious agent from the patient’s body.

On the other hand, cure means eradication of the cause of the illness — the complete removal of the pathogen from the body; for example, there is a cure for malaria or tuberculosis, but not yet for HIV.

You need to understand that antiretroviral therapy for HIV does not cure HIV, because it cannot eradicate the virus from the body. Even though effective treatments to control HIV exist now, there is still no cure. It is important that you make sure all the PLHIV in your care also understand this, for the following reasons:

• HIV treatment is for life: It will be easier for PLHIV to understand that, because it is not curative, HIV treatment will be for the rest of their lives, and they must continue taking the drugs even though they may have adverse side-effects (which will be covered later in this study session).
• Drug resistance: You will be better placed to explain to PLHIV that if treatment is interrupted, HIV may become drug resistant, that is, the virus in their bodies will not respond to treatment in future because the virus is no longer susceptible to the drugs. If this happens, it will be necessary to use other drugs that may not be as effective in keeping the virus levels in the blood down, or that may have more side-effects (drug resistance will be referred to again later in this study session).
• Minimising risk of transmission: Since there is still no vaccine to prevent HIV, you will need to educate and discuss prevention strategies with PLHIV consistently. They must understand that they are still able to transmit HIV to a healthy uninfected person, even if they feel healthier because they are on ART.

22.2  The benefits of ART

The benefits of ART can be divided into three — benefits to PLHIV, benefits to the health service, and benefits to the community at large, as described below.

Benefits of ART to the patient:

• Prolongs life and improves quality of life.
• Decreased stigma surrounding HIV infection, since treatment is now available.
• Households can stay intact, because patients survive for so much longer.
• Businesses and jobs can stay intact for the same reason.
• Reduces mother-to-child transmission of HIV.
• Less money is spent on treating opportunistic infections and providing palliative care (end-of-life care).

Benefits of ART to the health service:

• Increased number of people who accept HIV testing and counselling, because treatment is available.
• Increased motivation of health workers, since they feel they can do more for PLHIV.

Benefits of ART to the community:

• Decreased number of orphans.
• Increased awareness of HIV in the community, since more people accept HIV counselling and testing.

22.3  Antiretroviral drugs (ARVs) and antiretroviral therapy (ART)

In Study Session 20, you learnt that HIV is a virus. In fact, there are many types of viruses. The classification of viruses is very complex, and explaining it here would go beyond the scope of this study session. For your work as a Health Extension Practitioner, you only need to know that HIV is a type of virus that is termed a retrovirus. Hence, drugs that are used to treat HIV infection are called antiretroviral drugs, which can be shortened to ARVs.

Antiretroviral therapy (HIV treatment), also known as ART, is a treatment that uses ARV drugs. The two main goals of ART are:

1. to reduce the number of viruses in the patient’s blood to a very low level
2. to increase the number of CD4 lymphocytes in the patient as much as possible, to increase the body’s immunity to infection, including immunity against HIV.

Lymphocytes are a type of white blood cell involved in the immune system; CD4 lymphocytes (or CD4 cells) are a specialised type of lymphocyte, which stimulate all the other defensive mechanisms in the immune system. For this reason, they are sometimes also called ‘helper T cells’.

Remember from Section 20.2 that once inside the body, HIV first infects a previously uninfected CD4 lymphocyte. Then the HIV-infected CD4 lymphocyte produces many copies of the virus that are released into the blood to infect other CD4 lymphocytes, and so the process goes on, again and again. The ARV drugs work to stop this cycle by acting at different stages of the process.

22.3.1  Groups of ARV drugs

There are three big groups of ARV drugs available in Ethiopia, as listed below:

1. The NRTI drugs: this stands for ‘Nucleoside and Nucleotide Reverse Transcriptase Inhibitors’ (divided into NsRTIs and NtRTIs).
2. The NNRTI drugs: this stands for ‘Non-Nucleoside Reverse Transcriptase Inhibitors’.
3. The PI drugs: this stands for ‘Protease Inhibitors’.

Note that you don’t need to know the complex mechanisms of action of these drugs. Likewise, you don’t need to memorise the names of the drug groups.

Table 22.1 lists the commonly used ARV drugs in Ethiopia, arranged into the various groups, together with some rarely used drugs. But be aware that the table is not a complete list of all the ARV drugs; for example, it does not include all the rare drugs, or drugs that are not yet available in most resource-constrained settings like Ethiopia. You can use Table 22.1 as a reference in case a patient asks you about a specific drug, but remember to refer him or her to a health centre for more detailed advice than you can give at health post level. The drugs listed in the first three columns of Table 22.1 are the ones most widely used in Ethiopia, and we will say more about them later in this study session (Sections 22.3.3 and 22.4).

22.3.2  Why is the combination of three antiretroviral drugs necessary?

Combination therapy, in the context of HIV/AIDS, means prescribing three or more ARV drugs to be taken together. Combination therapy is useful for many reasons. Here are the most important ones.

22.3.3  How are antiretroviral drugs combined?

A prescribed or recommended collection of medications intended to treat a disease is called a treatment regimen (or simply a regimen). The regimens used in ART can be first line, second line, or even third line.

First-line drug regimens and fixed-dose combinations

First-line ARVs (Box 22.1) are mainly given twice a day. But there are some drugs which are given once a day, like Efavirenz (EFV) and Tenofovir disoproxil fumarate (TDF). Note that Abacavir (ABC) and TDF can also be used as first-line ARV drugs. According to the current Ethiopian ART guidelines, new adult and adolescent patients are not started on a d4T-containing regimen; instead they are prescribed AZT or TDF-containing regimens.

First-line drug regimens commonly include ARVs in fixed dose combinations, meaning combinations of three ARV drugs in fixed doses in the same tablet (e.g. AZT + 3TC + NVP in one tablet, see Figure 22.1a); this is taken twice a day (every 12 hours) except in the first two weeks of ART. There are also fixed drug combinations which contain two drugs in one tablet (e.g. AZT + 3TC), which is given with a third drug separately (e.g. Efavirenz or EFV, see Figure 22.1 b) in a different tablet.

Figure 22.1  Antiretroviral drugs: (a) A fixed-dose combination of Lamivudine (3TC), with Zidovudine (AZT or ZDV) and Nevirapine (NVP) in single tablets. (b) A single drug, Efavirenz (EFV), which may be taken in addition to other ARV drugs. (Photos: Basiro Davey)

22.4  ARV side-effects and how to manage them

Every drug can have side-effects, which means unwanted effects that result when taking the drug for treatment. ARV drugs can have multiple side-effects, some of which are common, and others which are rare. The most common side-effects of ARV drugs are shown in Table 22.2. You may need to advise patients when some of these occur, or refer them to a nearby health centre or hospital if serious side-effects arise.

Note that side-effects such as nausea, vomiting and diarrhoea are very common with many ARV drugs, especially in the first 2–3 weeks of treatment. If a patient has nausea, you should advise him/her to take the tablets with food (or just after eating food). Patients who develop diarrhoea should be advised to drink more fluids, including oral rehydration salts, eat small and frequent meals, and avoid spicy foods. If the nausea, vomiting or diarrhoea worsens, the patient should be referred to a health centre or hospital as soon as possible.

Summary of Study Session 22

In Study Session 22, you have learned that:

1. Antiretroviral therapy (ART) means giving antiretroviral (ARV) drugs to people who are HIV-positive to reduce the level of viruses in their bodies and increase the number of CD4 lymphocytes.
2. There are three big groups of ARVs (NRTIs, NNRTIs and PIs).
3. The standard regimen in ART is to give a combination of three different ARV drugs for maximum possible treatment effect, and to overcome or delay the development of drug resistance by HIV. Prescribing only one ARV drug increases the risk of resistance developing quickly to that drug.
4. ART has many benefits, including improving the quality of life for patients, decreasing stigma and discrimination, prevention of transmission of the virus from mother to child, and increasing uptake of other HIV services, like counselling and testing.
5. First-line drug regimens are given to patients who have never taken ARV drugs previously. If these combinations fail, or the patient experiences severe side effects, different second-line or even third-line drug combinations can be prescribed, but these are more expensive and may be less effective.
6. The most common side-effects of ARV drugs are nausea, vomiting, diarrhoea and headaches, especially in the first few weeks of ART. Examples of serious side effects which require urgent referral are severe abdominal pain, fever, yellow eyes, tingling and numbness, fatigue with shortness of breath, yellow eyes, pallor (anaemia) and skin rash.

Self-Assessment Questions (SAQs) for Study Session 22

Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering the following questions. Write your answers in your Study Diary and discuss them with your Tutor at the next Study Support Meeting. You can check your answers with the Notes on the Self-Assessment Questions (SAQs) at the end of this Module.

First read Case Study 22.1, and then answer the question that follows it.