Introduction

Since July 1 2015, changes to the Pharmaceutical Benefits Scheme (PBS) have vastly increased community access to high cost human immunodeficiency virus (HIV) antiretroviral therapy (ART). It was estimated that 26,800 people were living with HIV in Australia in 2013. These patients may now access their ART medications from any hospital pharmacy, community pharmacy, and certain dispensing doctors. Healthcare professionals, regardless of their area of practice, now play an even greater role in promoting the quality, safe and efficacious use of these medications.

These PBS changes reflect the commitment of Government and healthcare agencies to the Seventh National HIV Strategy 2014–2017. This strategy aims to reduce HIV disease burden within the community by reducing transmission and improving access to treatment.

Background Information

HIV compromises a person’s immune system by weakening their surveillance and defence systems against infections and certain types of cancer. Infected individuals progressively become immunodeficient as the virus destroys and impairs the function of immune cells in the body. Immune function is normally measured by the CD4 cell count as these T-lymphocytes play a crucial role in the immune response. The viral load represents the number of HIV RNA copies per millilitre of blood and is used to monitor treatment response and disease progression.

Following initial infection with HIV, there is a period of high level viraemia. This is associated with immunosuppression which can be measured by a marked decrease in CD4 lymphocyte count. After approximately three weeks, the individual may suffer seroconversion with a brief influenza-like illness characterised by fever, pharyngitis, lymphadenopathy, rash, splenomegaly and infrequently aseptic meningitis. These acute symptoms of infection resolve as the immune system mounts an antiviral response which significantly decreases the viral load. During this time, a rebound increase in CD4 cell counts to near baseline levels places the individual in a period of clinical latency, despite very high levels of viral replication, particularly in lymphoid tissue. The viral load then plateaus to the virological ‘set point’; a specific level of viraemia. If left untreated, the individual experiences an ongoing decline in CD4 cell count, with a median loss of 80 cells/μl per year.

Immunodeficiency results in increased susceptibility to a vast range of infections and diseases which healthy immune systems can normally fight. Opportunistic infections, certain malignancies or other severe clinical manifestations may present when a patient’s CD4 cell count has fallen to below 200 cells/μL. This usually indicates that the virus has reached its most advanced stage of infection, known as acquired immunodeficiency syndrome (AIDS). This can take between two to 15 years to develop, depending on the individual.

Common HIV Medication Groups and Their Side effects

Treatment is usually undertaken by specialists in HIV medicine with the following goals:

  • To restore and preserve immune function
  • To improve quality and length of life
  • Reduce HIV-related morbidity
  • For maximal and durable suppression of viral load (undetectable on assay), and
  • To prevent HIV transmission

Table 1 below indicates the main classes of HIV ART medications and their common side effects.

Table 1. Bioavailability of drugs eligible for IV to oral switch therapy. * Adverse effects of integrase inhibitors are difficult to establish due to poor study design.

Drug Class Mode of Action Medication Names Common Adverse Effects
Nucleoside reverse transcriptase inhibitors Metabolites of active phosphorylated NRTI inhibit viral reverse transcriptase and viral DNA synthesis, preventing HIV replication
  • Abacavir
  • Didanosine
  • Emtricitabine
  • Lamivudine
  • Stavudine
  • Zidovudine
Headache, nausea, vomiting, anorexia, myalgia, peripheral lipoatrophy (particularly long-term treatment, more common with stavudine), asymptomatic hyperlactataemia
Non-nucleoside reverse transcriptase inhibitors Reversibly inhibit HIV 1 reverse transcriptase, reducing viral DNA synthesis
  • Efavirenz
  • Etravirine
  • Nevirapine
  • Rilpivirine
Rash (may be severe, occasionally fatal), malaise, nausea, vomiting, elevated liver enzymes, headache, fever
HIV protease inhibitors Inhibit HIV 1 and HIV 2 proteases, preventing viral maturation and replication
  • Atazanavir
  • Darunavir
  • Fosamprenavir
  • Indinavir
  • Lopinavir with Ritonavir
  • Ritonavir
  • Saquinavir
  • Tipranavir
Headache, diarrhoea, nausea, vomiting, abdominal pain, elevated liver enzymes, fat accumulation, weight gain, hyperglycaemia (less likely with atazanavir), new onset or worsening diabetes, hypertriglyceridaemia, hypercholesterolaemia
Integrase inhibitors Inhibit HIV integrase, which prevents viral replication by stopping insertion of viral DNA into the host DNA
  • Dolutegravir
  • Elvitegravir
  • Raltegravir
Headache, fatigue, nasopharyngitis, increased liver enzymes, increased creatine kinase, rash*
Fusion Inhibitors Binds to viral glycoprotein subunit gp41 and, by inhibiting its function, blocks viral fusion with the CD4 receptor of the host cell and thus viral entry to the cell
  • Enfuvirtide
Injection site reactions peripheral neuropathy, insomnia, depression, cough, dyspnoea, loss of appetite and weight, arthralgia, eosinophilia, infections, lymphadenopathy
CCR5 Antagonists Prevents the entry of CCR5-tropic (R5) strains by selectively binding to the CCR5 receptor
  • Maraviroc
Constipation, rash, itch, fever, cough, infections (including upper respiratory tract and herpes simplex infections), myalgia, muscle spasms, increased creatine kinase, paraesthesia, dysaesthesia, disturbed sleep, bladder problems, neutropenia
Nucleotide Analogues Metabolite inhibits viral polymerases and terminates the DNA chain after incorporation into viral DNA
  • Tenofovir
Nausea, vomiting, diarrhoea, flatulence, weakness, headache, dizziness, hypophosphataemia

Medications from different classes are often given in combination in order to target the various stages of HIV replication and reduce the risk of resistance occurring.

Pharmacist’s Role In Promoting Adherence

Pharmacists have a major role to play in the monitoring and supporting of adherence. It is vital that the individual living with HIV uses their ART medications consistently and effectively to prevent resistance and sustain a reduction in viral load and HIV transmission. Whilst 100% adherence to ART medications is ideal, it is suggested that 95% adherence may be effective as newer medicines may be more forgiving of an occasional missed dose. HIV infected individuals will be on lifelong ART medication, therefore maintaining long-term adherence is critical. Alternative therapy regimens are used in cases of resistance and these tend to be more complex, require a greater number of tablets to be taken, and often involve medicines with poorer tolerability. This may lead to treatment failure which creates an unnecessary burden on the individual’s own health and the nation-wide health care system.

Protecting The Consumer’s Privacy

With increased access to these medications, it is crucial to maintain the consumer’s privacy and confidentiality. It is important to ensure that all staff are aware of these issues when dealing with sensitive medications. Patients should be reassured that measures are taken to protect their privacy at all costs, as individuals living with HIV may often be fearful of stigma or discrimination. Real or perceived stigma may be a barrier to access in health care, which has been noted to be particular issue in population groups such as Aboriginal and Torres Strait Islander people from small communities.

Conclusion

As all community pharmacies and private hospitals are now able to dispense HIV ART, healthcare professionals have an opportunity to play a greater role in the management of this chronic condition. The removal of one of the barriers of access to these highly specialised and high cost medicines has the potential to improve the lives of Australians living with HIV. Healthcare professionals should refresh their knowledge of these medicines and understand their obligations when promoting adherence and protecting patient’s privacy rights.

References:

  1. Antiretrovirals. In: Rossi S, editor. Australian Medicines Handbook 2015. Adelaide: Australian Medicines Handbook Pty Ltd; 2015.
  2. Australasian Society for HIV Medicine. Antiretroviral guidelines: Australian commentary on the US Department of Health and Human Services (DHHS) guidelines for the management of HIV-1 infected adults and adolescents. Surry Hills: Australasian Society for HIV Medicine; 2014.
  3. Australasian Society for HIV Medicine. General Practitioners and HIV. Darlinghurst: Australasian Society for HIV Medicine; 2015.
  4. Crooks, L.  Community pharmacy and HIV. Deakin West: Pharmaceutical Society of Australia Ltd; 2015.
  5. McAllister J, Beardsworth G, Lavie E, MacRae K, Carr A. Financial stress is associated with reduced treatment adherence in HIV-infected adults in a resource-rich setting. HIV Med. 2013; 14(2): 120-4.
  6. The Kirby Institute. HIV, viral hepatitis and sexually transmissible infections in Australia Annual Surveillance Report 2014. Sydney: The University of New South Wales; 2014.
  7. World Health Organization. Global Health Observatory (GHO) data HIV/AIDS. Geneva: World Health Organization; 2015.
  8. World Health Organization. HIV/AIDS fact sheet No360. Geneva: WHO; 2014.

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