7.3: Introduction to HIV, AIDS, and Antiretrovirals
By the end of this section, you should be able to:
- 7.3.1 Describe the pathophysiology of HIV and AIDS.
- 7.3.2 Identify clinical manifestations related to HIV and AIDS.
- 7.3.3 Identify common risk factors for HIV transmission.
- 7.3.4 Identify etiology and diagnostic studies related to HIV and AIDS.
- 7.3.5 Identify characteristics of drugs used to treat HIV and AIDS.
- 7.3.6 Explain the indications, actions, adverse reactions, and interactions of drugs used to treat HIV and AIDS.
- 7.3.7 Describe the nursing implications of drugs used to treat HIV and AIDS.
- 7.3.8 Explain the client education related to drugs used to treat HIV and AIDS.
Pathophysiology
The human immunodeficiency virus (HIV) is responsible for causing deterioration in the infected individual’s immune system, leaving them vulnerable to a variety of opportunistic infections and cancers. This state of immunodeficiency is known as acquired immunodeficiency syndrome (AIDS) . Since HIV was first identified in the 1980s, highly effective medications for antiretroviral therapy (ART) have been developed to suppress the virus and delay the development of AIDS-defining illnesses such as Pneumocystis jirovecii pneumonia (PJP; previously known as Pneumocystis carinii pneumonia or PCP), cytomegalovirus (CMV) infection, and the cancer known as Kaposi’s sarcoma. However, HIV infection is a lifelong condition with no known curative treatment.
After the individual’s initial exposure to HIV, the virus targets the CD4 T lymphocytes (helper T cells). It binds to and fuses with the CD4 cell and then enters it. From there, the enzyme reverse transcriptase takes the HIV RNA and forms a complementary strand of DNA. The enzyme integrase then incorporates the viral DNA into the individual’s DNA, which causes the host cell to begin producing viral proteins. The enzyme protease then cuts the viral proteins into their mature form, and the new copy of the virus is ready to bud off from the infected cell to go infect a new CD4 cell (Figure 7.4). As this process continues, there is continual degradation in the number of CD4 cells available to fight infection, and the person becomes immunocompromised and more at risk for various opportunistic infections and cancers. Once an individual develops one of these opportunistic illnesses or their CD4 cell count drops <200 cells/mL of blood, they are considered to have AIDS. People with AIDS have badly damaged immune systems. Understanding the life cycle of the virus is important because these steps present different drug targets that can be used to suppress viral replication. HIV treatment can slow or prevent progression of the disease. There are three stages of HIV. The first stage is acute HIV infection, in which clients have a large amount of HIV in their blood and are very contagious. Many have flu-like symptoms. Stage two is chronic HIV infection, also called asymptomatic HIV infection or clinical latency. HIV is still active, and the client can still transmit the infection to others as it continues to reproduce in the body. The third stage is when the client is diagnosed with AIDS. This is the most severe form of HIV. Clients have a high viral load and can easily transmit the virus.
Adverse Effects and Contraindications
Antiretroviral agents are known to cause gastrointestinal discomfort, including nausea, vomiting, and diarrhea. A contraindication to any antiretroviral drug is known hypersensitivity.
The most common adverse effects associated with enfuvirtide include fatigue, diarrhea, and injection site reactions.
Common adverse effects among the protease inhibitors include liver injury and metabolic disorders such as dyslipidemia and glucose intolerance.
Safety Alert
Protease Inhibitors
Effective ART therapy has allowed many clients with HIV to live decades longer than they might have if diagnosed in the 1980s. Protease inhibitor use, however, can increase the risk for metabolic complications in these clients, including raising serum glucose and lipid levels. This may predispose them to conditions such as diabetes and atherosclerotic cardiovascular disease (e.g., angina, myocardial infarction). As these clients age, health care professionals should screen for these metabolic conditions to be able to intervene before complications develop.
The main adverse effects seen with maraviroc are gastrointestinal upset and upper respiratory infection.
Common adverse reactions to the NNRTIs include rash, insomnia, and liver injury. Use of this class of drugs is on the decline due to poor tolerability and safety issues.
Older, first-generation NRTIs such as didanosine and zidovudine are more frequently associated with adverse effects such as peripheral neuropathies, pancreatitis, and lactic acidosis. Newer agents such as abacavir and tenofovir tend to be better tolerated and are included in many of the recommended regimens for HIV treatment.
Table 7.10 is a drug prototype table for antiretroviral drugs featuring dolutegravir/rilpivirine. It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
|
Drug Class
Integrase strand transfer inhibitor Mechanism of Action Binds to the integrase active site and inhibits the strand transfer step of HIV DNA integration necessary for HIV replication |
Drug Dosage
50 mg of dolutegravir and 25 mg of rilpivirine once daily. |
|
Indications
HIV infection Therapeutic Effects Suppresses HIV replication and preserves the immune system |
Drug Interactions
Aluminum hydroxide Carbamazepine Dofetilide Efavirenz Fosamprenavir Food Interactions Dairy products |
|
Adverse Effects
Increased serum lipase Pruritis Hyperglycemia Abdominal distress Hepatitis |
Contraindications
Hypersensitivity Caution: Hepatotoxicity Immune reconstitution syndrome |
Nursing Implications
The nurse should do the following for clients who are taking antiretroviral drugs:
- Monitor for signs and symptoms of anaphylaxis (e.g., shortness of breath, difficulty breathing, difficulty swallowing).
- Advise the client to take the entire prescribed course of the drug to ensure adequate treatment and to reduce the development of drug resistance.
- Teach the client to monitor for symptoms of lactic acidosis (e.g., abnormal heartbeat, muscle cramps, abdominal pain).
- Educate about sterile, proper injection technique if the client is using enfuvirtide.
- Monitor for potential CYP3A4 interactions with other medications the client is taking if they are using ritonavir or cobicistat.
- Monitor for liver dysfunction in clients receiving maraviroc.
- Evaluate for the presence of the HLA-B*5701 genetic mutation before beginning abacavir because its presence increases the risk for anaphylaxis.
- For clients receiving protease inhibitors, monitor for changes in serum lipids and glucose to reduce the risk for heart disease.
- Provide client teaching regarding the drug and when to call the health care provider. See below for client teaching guidelines.
Client Teaching Guidelines
The client taking an antiretroviral should:
- Alert their health care provider about any signs of allergic reactions, including throat swelling, severe itching, rash, or chest tightness.
- Alert their health care provider that they are taking these medications, including the dose and frequency.
- Take the drug with food if it causes an upset stomach.
- Take a missed dose as soon as they remember; however, they should not take double doses.
- Alert their health care provider about any adverse effects or barriers to taking the medication correctly to ensure adherence and appropriate drug selection.
- Understand proper sterile injection technique to reduce the risk for infection.
- Report any rash or yellowish skin discoloration if they are taking maraviroc.
- Make sure to take every dose in their regimen to decrease the development of viral resistance.
- Make sure to practice safer sex (e.g., condom use, fewer sexual partners) and avoid sharing needles to reduce the chances of transmitting HIV.
FDA Black Box Warning
HIV and AIDS Medications
Abacavir: Serious and sometimes fatal hypersensitivity reactions, with multiple organ involvement, have occurred with abacavir. Clients who carry the HLA-B*5701 allele are at a higher risk for a hypersensitivity reaction to abacavir, although hypersensitivity reactions have occurred in clients who do not carry the HLA-B*5701 allele.
Maraviroc: Hepatotoxicity has been reported with use of maraviroc. Severe rash or evidence of a systemic allergic reaction (e.g., eosinophilia, elevated immunoglobulin E [IgE], fever) prior to the development of hepatotoxicity may occur. Clients with signs or symptoms of hepatitis or allergic reaction following use of maraviroc should be immediately evaluated.