HAART, THE HEART AND THE POTENTIAL FOR INTERACTION

Editor,

Approximately 103,800 people in the UK are living with human immunodeficiency virus (HIV) as a chronic disease, reflecting the major impact of highly active antiretroviral therapy (HAART). Physicians will be familiar with links between HIV and acute coronary events^{1, 2} but may be less familiar with potential interactions between HAART and cardiovascular medication. We describe a patient living with HIV who underwent primary percutaneous coronary intervention (PPCI) with stent implantation for acute myocardial infarction, along with some important therapeutic considerations that were required to optimise his cardiovascular prognosis.

A 47-year old man presented with acute chest pain for 4 hours and was diagnosed with ST-elevation myocardial infarction. He underwent PPCI with stenting of an acutely occluded proximal left anterior descending coronary artery. An echocardiogram showed impaired left ventricular systolic function with an ejection fraction of 30%. Standard therapy with aspirin and ticagrelor were commenced along with eplerenone, atorvastatin, ramipril and bisoprolol.

The patient was HIV-positive, well controlled on HAART comprising a combination of emtricitabine/tenofovir and efavirenz. Since 1999 the University of Liverpool has maintained a free HIV drug interaction resource which enables healthcare professionals to check HAART against any new medication being initiated. It provides a traffic light system demonstrating the strength of any potential interaction, a summary of the evidence and the specific effect expected. The Table summarises its comments relating to interactions with antiplatelet therapy.

Table.

Potentially important effects of antiretroviral drugs on the efficacy of antiplatelet agents³. Those relevant to this patient are highlighted in bold

	Clopidogrel	Ticagrelor	Prasugrel
Emtricitabine	Unlikely to affect	Unlikely to affect	Unlikely to affect
Tenofovir	Unlikely to affect	Unlikely to affect	Unlikely to affect
Efavirenz	May diminish efficacy	May diminish efficacy	Unlikely to affect
Etravirine	May diminish efficacy	May diminish efficacy
Abacavir	May diminish efficacy	Unlikely to affect	Unlikely to affect
Nevirapine	May enhance efficacy	May diminish efficacy
Darunavir/Ritonavir	Likely to diminish efficacy	Likely to enhance efficacy	Unlikely to affect
Darunavir/Cobicistat	Likely to diminish efficacy	Likely to enhance efficacy	Unlikely to affect
Atazanavir	Likely to diminish efficacy	Likely to enhance efficacy	Unlikely to affect
Fosamprenavir	Likely to diminish efficacy	Likely to enhance efficacy	Unlikely to affect
Indinavir	Likely to diminish efficacy	Likely to enhance efficacy	Unlikely to affect
Lopinavir	Likely to diminish efficacy	Likely to enhance efficacy	Unlikely to affect
Saquinavir	Likely to diminish efficacy	Likely to enhance efficacy	Unlikely to affect
Tipranavir	Likely to diminish efficacy	Likely to enhance efficacy	Unlikely to affect
Dolutegravir	Unlikely to affect	Unlikely to affect	Unlikely to affect

Because efavirenz could potentially decrease ticagrelor efficacy due to induction of cytochrome P450 3A4, we switched from ticagrelor to prasugrel. Additionally, because of potential interactions between efavirenz, atorvastatin and eplerenone, we switched the latter two to rosuvastatin and spironolactone.

HAART has been a key development in modern medicine, achieving a life expectancy for people living with HIV close to that of the HIV-negative population⁴. Primary PCI is another major advance, but relies on effective dual antiplatelet therapy to prevent stent thrombosis, a highly-lethal early complication⁵.

Clinical teams should be aware of potential overlaps between HAART and cardiovascular medicines, as well as a valuable resource that guides the selection of agents least likely to be compromised by co-prescription with HAART.