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Supporting Patients with HIV through Community Pharmacy

Tim Roberts - Sexual Health - CPD

ITK Connect May 2016 - Tim Roberts - Sexual Health - CPDAn estimated 26,800 Australians were living with HIV at the end of 20131. HIV is different now; the management of HIV has changed significantly over the past 30 years, with Antiretroviral Therapy (ART) medicines re-shaping the natural progression of HIV and being introduced to patients earlier in the course of infection. One of the priority areas of the 7th National HIV strategy 2014-2017 is to improve access to and uptake of ART medications, with community pharmacies being able to dispense ART medications from July 15th 20152. This places community pharmacists in an ideal position to raise awareness, provide medicines education and tailor support to patients who are living with HIV in their local communities.

HIV around the Globe

HIV continues to be a significant global public health issue, with estimates of between 33-37 million people living with HIV at the end of 2013 and approximately 2-2.5 million people becoming newly infected with HIV in 2013 across the globe3. Sub-Saharan Africa is the most affected region globally, with 23-26 million people living with HIV in 20133. The total number of people living with HIV in high-income countries is high, largely due to the widespread access to ART medicines compared to developing countries, which prolongs the lives of HIV positive people. The World Health Organization (WHO) is committed to global health sector strategies to cover HIV/AIDS, viral hepatitis and sexually transmitted infections (STI’s), with the 2016-2021 strategy due to be finalized for consideration by the 69th World Health Assembly in 2016.

HIV in Australia

Since the virus was identified over 30 years ago, Australia has done well by international standards in keeping infection rates down, however since 1999 there has been a small (but significant) yearly increase in the number of newly diagnosed people with HIV. A total of 1,236 cases of HIV infection were newly diagnosed in Australia in 2013 which represents a gradual increase from 724 diagnoses in 1999.

An annual surveillance report published by the Kirby institute in 2014 notes the current HIV prevalence among key populations in Australia as the following1;

  • HIV occurs at high levels among men who have sex with men (prevalence of 8-12% among gay community-attached men)
  • HIV is low among people who inject drugs (prevalence of 1 – 2% among people attending needle and syringe programs)
  • HIV remains extremely low among female sex workers (<0.1% prevalence)
  • HIV prevalence among Aboriginal and Torres Strait islander people is estimated a 0.15%, however rates of HIV diagnoses in 2013 were greater among Indigenous Australians (5.4 per 100,000) compared to Australian born non-Indigenous population (3.9 per 100,000) with a greater incidence of HIV cases attributed to injecting drug use or heterosexual contact compared with non-indigenous cases.
  • 313 cases of HIV infection newly diagnosed in 2013 were attributed to heterosexual contact, of these cases 46% were in people from high-prevalence countries (or their partners).

The 7th National HIV strategy 2014-2017 set a target of a 50% reduction in new infections and an increase in the uptake of treatment to 90%2. The Kirby institute annual surveillance report also estimated that in 2013, approximately 13,200 – 19,500 of the estimated 26,800 people living with HIV in Australia were receiving ART treatment and had undetectable levels of HIV1.

Pathogenesis, HIV Life-Cycle and ART mechanisms

HIV is a single-stranded ribonucleic acid (RNA) virus with an outer envelope that surrounds two copies of single stranded RNA along with a number of viral proteins4. HIV replication commences when the virus envelope glycoprotein 120 (GP120) attaches to CD4 receptors on the surface of CD4 lymphocytes (this process is called binding) and fusion of the virion membrane allows cell entry. Once inside the cell, the RNA is converted to deoxyribonucleic acid (DNA) via the reverse transcriptase enzyme and then migrates to the cell nucleus and integrates (as proviral DNA) into the host cell DNA through the integrase enzyme4. This process of replication is what classes HIV as a retrovirus, the integrated viral DNA accelerates the production of components for new virions which then bud off the cell in an immature state. As the virions mature they undergo a process of proteolytic cleavage (by the protease enzyme) and the mature virion then binds to the receptor on CD4, repeating the cycle again4.

CD4 cells are vital to human function, they are produced when the immune system attempts to fight infections and in a person infected with HIV the production of CD4 cells is also replicating and proliferating HIV.

Recognizing the life cycle of HIV and its proliferation process is important in regards to the various mechanisms of action for different drug classes of ART below4,5,6;

  • Binding Inhibitors: Act on the host cell to block binding of HIV to the cell receptor
  • Fusion inhibitors: Prevent the virus from entering the cell by blocking its fusion to the cell membrane
  • Nucleoside Reverse Transcriptase Inhibitors (NRTIs) and Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs): Inhibits reverse transcriptase (by which RNA is converted to DNA)
  • Integrase Strand Transfer Inhibitors (INSTIs): prevent the integration of viral DNA into the host DNA of the cell nucleus, by inhibiting HIV integrase
  • Protease Inhibitors (PIs): Inhibit protease in the final stage of viral assembly, preventing viral maturation and replication
  • Pharmacokinetic boosters/enhancers: Used with either PIs or INSTIs to increase their performance.

Clinical Features and co-morbidities

Following infection with HIV there is a period of very high viral load (viraemia), sometimes in excess of 1 million HIV RNA copies/ml4. More than half of people who contract HIV develop a seroconversion illness which is characterised by fever, pharyngitis, lymphadenopathy, rash, splenomegaly and aseptic meningitis7. However, other people living with HIV may be asymptomatic or have a subclinical presentation of the disease, despite having a high viral load4,7.

Symptoms of acute HIV infection typically resolve as the immune system responds, there is a rebound increase in CD4 cell count to near baseline levels and the affected person enters a period of clinical latency8. The plasma HIV RNA plateaus to a level or viraemia known as the ‘virological set point’, very high levels of viral replication decrease however replication does continue7.

If left untreated, a gradual decline in CD4 cell count (median loss 80 cells per year) occurs. The progression to Acquired Immunodeficiency syndrome (AIDS) is marked by the development of opportunistic infections/conditions or specific malignancies (usually when CD4 cell count has fallen below 200 cells/mm3 and the person is severely immunocompromised (occurs at a median of 10 years after initial infection)4,7.

Viral Load and HIV Transmission

Viral load is a quantitative test which measures the number of viral particles in the serum of a person with HIV. The test is sensitive down to approximately 20copies/ml, if no HIV is identified in a viral load test the sample is said to be undetectable (or below the limits of detection)7. Viral load is seen as the most accurate measure of viral activity, and therefore an indicator of transmission risk.

As mentioned above, viral load can be at its highest when HIV is first contracted, a rise in viral load is usually detectable before a drop in CD4 cell count. It is for this reason that a person newly infected with HIV may transmit the virus before they have been diagnosed with HIV.

An undetectable viral load reduces the risk of HIV transmission, though it should be noted that in some (small number of) people the plasma and semen viral loads may differ. Additionally, viral load may rebound quite quickly for a number of reasons including treatment cessation, development of resistance to treatment or due to other infections (in particular sexually transmittable infections)7. A number of studies suggest that sexual transmission from a person with an undetectable viral load is very low8,9.

High viral load greatly increases the chance of viral transmission of HIV, therefore to decrease transmission of HIV the viral load of people living with HIV must also be decreased. Some people will not be able to achieve an undetectable viral load and others may experience increases from time to time; for this reason people on treatment are encouraged to continue to use condoms with HIV-negative partners to reduce the risk of transmission4,7.

HIV can be transmitted by sexual intercourse, injection of blood (or through mucous membranes contaminated with blood), from mother to infant in-utero (quite low in Australia, due to effective treatment rates in pregnant women) and perinatally (through breastmilk). The transmission risk for HIV may also be increased when there are concomitant STIs present (such as Gonorrhoea, Chlamydia and Syphilis). HIV does not spread through casual social contact such as hugging, kissing and touching4.

Treatment and Management Strategies

HIV is a chronic condition that is manageable with a combination of ART medicines, for people who start treatment early the likelihood of experiencing HIV-related illness or AIDS is significantly reduced. Current treatments for HIV (irrespective of regime) are not a cure as eradication is not achievable, ART treatments are prescribed as lifelong therapy7.

The primary goals of ART are to:10;

  • Reduce HIV-associated morbidity and prolong the duration and quality of survival
  • Restore and preserve immunologic function
  • Maximally and durably suppress plasma HIV viral load and
  • Prevent HIV transmission.

ART has reduced HIV-related morbidity and mortality and has reduced perinatal and behaviour-associated transmission of HIV10,11. HIV suppression with ART may also decrease inflammation and immune activation thought to contribute to higher rates of cardiovascular and other end-organ damage reported in HIV-infected cohorts10.

In Australia, treatment decisions are guided by the Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine (ASHM) Australian Commentary on the US Department of Health and Human Services (DHHS) Guidelines for the Management of HIV-1 infected Adults and Adolescents10.

The current guidelines allow patients in Australia to be initiated on therapy regardless of CD4 level (and when the patient is ready to commence therapy). For a person commencing therapy, a once-daily regimen is usually started first (unless there is a clinical reason not to do so, such as identification of drug resistance or comorbidities to one or more of the active components)7,10. People commencing therapy are typically prescribed a combination of three medicines (including at least 2 different classes) with a normal regime consisting of dual NRTIs plus a third medicine such as a NNRTI, a PI (boosted with ritonavir) or an INSTI10,12,13.

For more treatment-experienced patients (many patients have been using ART for 20+ years), some may be taking more complex regimes in an attempt to avoid medicines to which resistance has been developed. It is not uncommon for these patients to be on combinations of five ART medications, in addition to treatments for other co-morbidities7,10.

Resistance to therapy can occur quite rapidly for people living with HIV as the virus can mutate easily (HIV has a number of subtypes and virions may carry slight mutations)>4. Certain mutations render some medications ineffective – which is an issue to consider in single-fixed dose regimes of medications; whilst the ease of use and compliance benefits are significant the development of resistance to one or more molecules in the fixed combination will mean that a change to regimen is required10.

Medications, Adverse Effects and Drug Interactions

There are a number of prescribing options available in Australia, table 1 (below) summarizes some of the more commonly used options. For treatment naïve patients, current starting recommendations include10;

Integrase Strand Transfer Inhibitor-Based Regimens:
  • Dolutegravir/abacavir/lamivudine—only for patients who are HLA-B*5701 negative
  • Dolutegravir plus tenofovir emtricitabine
  • Elvitegravir/cobicistat/tenofovir/emtricitabine—only for patients with pre-antiretroviral therapy CrCl >70 mL/min
  • Raltegravir plus tenofovir/emtricitabine
Protease Inhibitor-Based Regimen:
  • Darunavir/ritonavir plus tenofovir/emtricitabine
    Given the large number of options available for initial therapy, it is recommended that the selection of a regimen for a particular patient should be guided by factors such as virologic efficacy, toxicity, pill burden, dosing frequency, drug-drug interaction potential, resistance testing results, comorbid conditions, and cost10.

For simplicity and adherence purposes, the following single tablet regimes are available5,10;

  • tenofovir/emtricitabine + efavirenz (Atripla™)
  • tenofovir/emtricitabine + rilpivirine (Eviplera™)
  • tenofovir/emtricitabine + elvitegravir/cobicistat (Stribild™)
  • abacavir/lamivudine + dolutegravir (Triumeq™)

ITK Connect May 2016 - Tim Roberts - Sexual Health - CPD1

Adverse effects have been reported with the use of all antiretroviral (ARV) drugs and are among the most common reasons cited for switching or discontinuing therapy and for medication non-adherence10,14. Figure 1 (below) summarises some of the commonly experienced adverse effects across the different classes of ART. It is important to note that newer ART medications have a lower incidence of adverse effects than their older counterparts.

Figure 1. Common Adverse Effects of ART5, 10,14

ITK Connect May 2016 - Tim Roberts - Sexual Health - CPD2

Switching from an effective ARV regimen to a new regimen must be done carefully and only when the potential benefits of the change outweigh the potential complications of altering treatment. The fundamental principle of regimen switching is to maintain viral suppression10.

There is a significant potential for drug-drug interactions between ART medications and other medications in patients with HIV, with most drug interactions being mediated through inhibition or induction of hepatic drug metabolism through CYP450, p-glycoprotein and organic ion transporters1510. Drug-drug interactions can occur with numerous commonly prescribed non-HIV medicines and over the counter products.

Pre and Post Exposure Prophylaxis

Pre-exposure prophylaxis (PrEP) is the administration of antiretroviral medicine to an uninfected person who may be at risk of contracting HIV, to lower their risk of HIV infection. Some people may enquire about PrEP for their partners. PrEP is not currently a TGA-licensed indication, nor is it available in Australia on the PBS10.

Post-exposure prophylaxis (PEP) is the administration of HIV ART medicines soon after a high-risk exposure to HIV, to lower the risk of infection. It must be administered within 72 hours of exposure and the sooner the better, i.e. within hours rather than days10. PEP starter packs are available from hospital emergency departments, sexual health clinics and some high caseload GP clinics. Individuals requesting PEP should be referred to a hospital emergency department, HIV clinician or sexual health clinic.

Supporting Patients in Community Pharmacy

Community pharmacy has an important role to play in supporting patients with HIV in taking their medications. With the benefits of increased access to ART medications in community pharmacy, it may mean that more patients utilize their local community pharmacy for dispensing, advice and support. Pharmacists can support patients by considering the following;

  • Discuss, encourage and support adherence to HIV regimes. Ensuring consistent use of medications will assist in helping patients maintain a reduced viral load. Provide patients with options to support their medication taking, such as Dose Administration Aids, SMS script reminders or staged supply arrangements if appropriate.
  • Review non-HIV medications and complementary medicines for drug-drug interactions with ART regimes. Consider the benefits of recommending a Medscheck (or request referral for Home Medicines Review) to support patients. Useful drug interaction tables can be found at www.arv.ashm.org.au/arv-guidelines and www.hiv-druginteractions.org
  • Provide information to patients regarding relevant local support groups and organizations. National organisations include National Association of People Living with HIV (NAPLAH) and state based support is available also. Additionally, referrals to local sexual health clinics may be useful
  • Avoid contributing to stigma or discrimination, which can be significant concerns for people living with HIV. Consider that some pharmacy staff may not be familiar with interacting with people living with HIV and providing training to ensure that staff know there are no risks of contracting HIV through social contact, only blood-to-blood and sexual contact.

Additionally, although the increased accessibility of ART medicines in community pharmacy has been broadly welcomed by patients and prescribers, common concerns expressed from existing patients are in relation to discretion and privacy when collecting their medications in a community pharmacy. Whilst community pharmacies are adept at providing privacy to patients when counselling medications – consider the importance of discretion, confidentiality and privacy for patients receiving ART at the pharmacy and provide training to staff accordingly.

Assessment Questions

The assessment questions below can be found at the Guild Pharmacy Academy myCPD e-learning platform. Login or register at: www.mycpd.org.au

  1. Which of the following statements is INCORRECT regarding HIV prevalence in Australia?
    a. HIV occurs at the highest levels among men who have sex with men
    b. The total number of diagnosed HIV infections per year has been gradually decreasing since 1999
    c. HIV is extremely low among female sex workers
    d. An estimated 13,200 to 19,500 people living with HIV in Australia are being treated with ART medications
  2. Which of the following best describes the action of the ART emtricitabine in the HIV life-cycle?
    a. Prevents the integration of viral DNA into the host DNA of the cell nucleus
    b. Acts on the host cell to block binding of HIV to the cell receptor
    c. Prevents the virus from entering the cell by blocking its fusion to the cell membrane
    d. Inhibits reverse transcriptase (by which RNA is converted to DNA)
  3. Which of the following statements is true regarding the transmission of HIV
    a. HIV cannot be passed on from mother to infant
    b. Kissing and sharing utensils may facilitate the transmission of HIV in patients with a high viral load
    c. The likelihood of HIV transmission from a person with an undetectable viral load is very minimal
    d. CD4 count is seen as a more accurate measure of viral activity than viral load
  4. Which of the following HIV regimes of ART contains a protease inhibitor?
    a. Dolutegravir + abacavir + lamivudine
    b. Tenofovir + emtricitabine + efavirenz
    c. Darunavir + tenofovir + emtrictabine
    d. Elvitegravir + cobicistat + tenofovir +emtricitabine
  5. Which of the following medications is most likely to cause mitochondrial toxicities?
    a. abacavir
    b. efavirenz
    c. elvitegravir
    d. maraviroc

References
1. The Kirby Institute. HIV, viral hepatitis and sexually transmissible infections in Australia annual surveillance report 2014. 2014.
2. Australian Government. Department of Health. Seventh national HIV strategy 2014–2017. 2014. At: www.health.gov.au/internet/main/publishing.nsf/Content/ohp-bbvs-hiv
3. World Health Organisation. HIV Factsheet. 2015 available at: www.who.int/mediacentre/factsheets/fs360/en/
4. Australasian Society for HIV Medicine. General practitioners and HIV. 2014.
5. [ Antiretrovirals ] [updated Jan 2015]. In: AMH [Internet]. Adelaide: Australian Medicines Handbook Pty Ltd.; 2015 Jan.
6. Pharmaceutical Society of Australia. HIV and Community Pharmacy. 2015.
7. Australasian Society for HIV Medicine. HIV Management in Australasia: a guide for clinical care. Sydney: ASHM; 2009.
8. Rodger A, Cambiano V, Bruun T, et al. HIV transmission risk through condomless sex if HIV+ partner on suppressive ART: PARTNER study. Boston, USA: 2014 Conference on Retroviruses and Opportunistic Infections (CROI).
9. Grulich A, Bavinton B, Jin F, et al. HIV transmission in male serodiscordant couples in Australia, Thailand and Brazil. Seattle, USA: 2015 Conference on Retroviruses and Opportunistic Infections (CROI). Abstract 1019LB.
10. PSA comm number 11 – ASHM ARV.
11. ART CC AC. Life expectancy of individuals on combination antiretroviral therapy in high-income countries: a collaborative analysis of 14 cohort studies. Lancet. Jul 26 2008;372(9635):293-299.
12. Australasian Society for HIV Medicine (ASHM). 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. At: www.arv.ashm.org.au.
13. Sansom LN, ed. Australian pharmaceutical formulary and handbook. 23rd edn. Canberra: Pharmaceutical Society of Australia; 2015.
14. O’Brien ME, Clark RA, Besch CL, et al. Patterns and correlates of discontinuation of the initial HAART regimen in an urban outpatient cohort. J Acquir Immune Defic Syndr. 2003;34(4):407-414.
15. Piscitelli SC, Gallicano KD. Interactions among drugs for HIV and opportunistic infections. N Engl J Med. Mar 29 2001;344(13):984-996.

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