Are you up to date with Australia’s new COVID-19 drugs?

Medical Forum·
Medical Forum Weekly
·3 mins read

The TGA recently approved Australia’s first oral treatments for COVID-19. Are you up to date with the associated clinical guidelines for these drugs?

Last week, the TGA granted provisional approval to Lagevrio and Paxlovid, two oral drugs for the treatment of COVID-19. The approval is hailed by experts as significant step forward in the fight against the SARS‑CoV‑2 virus. According to Dr Paul Griffin, Associate Professor of medicine at the University of Queensland, the two new drugs will make a big difference.

“Given these antiviral medications are administered orally, they can be used more in the community setting and have been shown to work well particularly at reducing the risk of going to hospital and progressing to more severe disease in people who are high risk of doing so when infected with the SARS-CoV-2 virus,” Prof Griffin said.

According to the TGA approval, the drugs are aimed at patients who do not require oxygen but are at increased risk of hospitalisation or death. Also, according to the TGA, the drugs should not be used as a substitute for COVID-19 vaccination.

About the new drugs
Lagevrio, also known as Molnupiravir, is available as capsules, and works by inhibiting replication of the SARS-CoV-2 virus.

Paxlovid consists of two drugs, nirmatrelvir and ritonavir, each presented as a tablet. Paxlovid works by targeting two components of the virus. The nirmatrelvir component of the drug aims to block the activity of a protease enzyme involved in virus replication. Ritonavir is an antiretroviral protease inhibitor, commonly used in the past for the treatment of HIV infection.

Clinical guidelines
According to the TGA, either of these two drugs should be administered as soon as possible after a COVID-19 diagnosis and within 5 days of the start of symptoms. According to the TGA release, either Paxlovid or Lagevrio should be taken twice a day for five days.

According to the TGA, the following adverse effects, contraindications and recommendations should be considered:

  • Paxlovid
    • Paxlovid should not be used in patients with severely reduced kidney or liver function and should not be used in combination with certain drugs, such as alfuzosin, pethidine, piroxicam, fentanyl, methadone, among several others. For a complete list of drugs that are contraindicated for use with Paxlovid, see Tables 1 to 3, from the TGA Paxlovid guidelines.
    • The drug is not recommended in pregnancy or breastfeeding, or in women of childbearing potential. Sexually active women of childbearing potential are recommended to use contraception.
    • According to TGA product guidelines, clinical data showed that among 1,109 participants who were COVID-19 positive and received Paxlovid, a total of 251 or 22.6% of participants reported adverse effects. Some of the side effects reported, and their frequency, include diarrhoea (3.1%), vomiting (1.1%), hypertension (0.6%), myalgia (0.6%), dysgeusia (5.6%) and headache (1.4%).
  • Lagevrio
    • Lagevrio has provisional approval for the treatment of adults with COVID19 who do not require initiation of oxygen due to COVID-19 and who are at increased risk for hospitalisation or death.
    • According to the TGA, Lagevrio is not recommended for use during pregnancy and breastfeeding.
    • Sexually active women of childbearing potential and men should use contraception during and 3 months after treatment with this drug.
    • According to the FDA the drug should not be used in patients under the age of 18, because it may affect bone and cartilage growth.
    • The most common side effect reported for this drug are diarrhoea, nausea, and dizziness. These side effects occurred in 1% to 2% of patients, according to clinical data reported by the TGA.

Any problems or side effects identified for these drugs should be reported to the TGA. For more information see the TGA website on reporting problems.

Additional information

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