Oral antivirals could be a ‘game changer’ in the ongoing treatment of COVID-19. While they can be effective in managing COVID, the new treatments are not without their own challenges.
Oral treatments such as nirmatrelvir/ritonavir (Paxlovid) and molnupiravir (Lagevrio) will soon be available for use to treat COVID-19 in Australia. The treatments have proven to significantly ease symptoms and reduce hospital admissions, but health professionals are concerned they also present an increased risk of drug interactions.
Molnupiravir can be taken after contracting COVID and can minimise symptoms and reduce the likelihood of hospitalisation and death.
Paxlovid has proven to be effective in treating people with mild to moderate COVID and who are at high risk of progressing to severe disease.
Both work by disrupting the virus’s ability to replicate inside cells and have been hailed as a breakthrough in the fight against the virus.
But hospital pharmacists are calling for a “consistent and streamlined approach” when prescribing and dispensing these drugs to prevent interactions with medicines commonly used by older people.
“Strong clinical data supports use of oral antiviral drugs, including Paxlovid, which is reported to reduce COVID-19-related hospital admission or death from any cause by 89 per cent in unvaccinated adults with risk factors for disease progression,” says co-author of a study published in the Journal of Pharmacy Practice and Research (JPPR), Professor Jason Roberts.
“However, potential drug interactions can be very challenging to interpret, predict and manage. A recent review of COVID-19 positive patients for infusion of sotrovimab, a COVID-19 treatment provisionally approved in 2021, found up to one in three patients would be potentially at risk of a significant drug interaction if they commenced Paxlovid therapy.”
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The authors say that prior to administering oral treatments, health professionals will need to assess a patient’s risk of disease progression against the potential for adverse outcomes associated with interacting medications.
To do this, they will quickly need nationally consistent guidance on safe and effective use of the new antiviral medicines well before GPs and pharmacists have access, Prof. Roberts told AJP.
“While it is important these novel medicines are imported and distributed quickly, at the same time we must generate a much stronger understanding of their risks and benefits – given limited international experience – and produce practical resources to assist Australian doctors and pharmacists on their safe and effective use in patients,” he said.
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“This will involve regular pharmacovigilance activities undertaken by hospital pharmacists and other healthcare professionals (including in community-based professionals), supported by robust data collection on effectiveness and safety during early use.
“More comprehensive data for any COVID-19 therapy would enable more Australians to derive maximum benefit, particularly in traditionally more vulnerable populations …”
Clear ‘black and white’ guidance is already available on the drug interactions for some medications that interact with Paxlovid, including some anti-seizure drugs, muscle relaxants, prostate cancer medicines and other anti-cancer treatments, as well as treatments for common heart conditions, gout, hypertension medicines and immunosuppressants.
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The main clinical challenge is where the recommendations for drug interaction management fall into a ‘grey’ zone. Pharmacists say that, with careful consideration of individual circumstances, use may be managed. But, due to limited clinical experience so far, nationally agreed management principles have not been made clear.
While Australia enjoys very high vaccination rates, the uncertain effects of oral antivirals in fully vaccinated individuals increases the importance of establishing and adopting nationally consistent guidance.
“This is particularly important in the context of limited availability and access to these medications,” say the authors.
“Data collection of the effectiveness and safety of these agents is essential to generate a much stronger understanding of the risks and benefits of these drugs in the patient population that are used.”
Do you take any of the drugs listed on the ‘black and white list’? Are you worried about interactions with ongoing COVID treatments? Why not share your thoughts in the comments section below?
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