其 他 安 全 警 示
|
| |
| The United Kingdom: Nirmatrelvir and ritonavir (Paxlovid▼): be alert to the risk of drug interactions with ritonavir (English only) |
| |
Medicines and Healthcare products Regulatory Agency (MHRA) announces that there is a risk of harmful drug interactions with the ritonavir component of the COVID-19 treatment Paxlovid due to its inhibition of the enzyme CYP3A, which metabolises many commonly used drugs.
Nirmatrelvir and ritonavir (Paxlovid 150mg/100mg film-coated tablets) is an anti-viral treatment that is indicated for the treatment of COVID-19. The ritonavir component of Paxlovid is not active against SARS-CoV-2 but inhibits the CYP3A-mediated metabolism of nirmatrelvir (the active antiviral), thereby increasing plasma concentrations of nirmatrelvir. It is this CYP3A inhibitory activity of ritonavir that poses a risk of harmful drug interactions with Paxlovid.
Harmful interactions can occur with many medicines. Section 4.3 of the Summary of Product Characteristics (SmPC) lists all the drugs with which Paxlovid is contraindicated and must not be co-administered, including commonly used medicines such as analgesics, antibiotics and antihistamines, and more specialized treatments such as antianginal drugs, anticancer drugs and anticonvulsants. Use of Paxlovid with these medicines may lead to serious or life-threatening side effects. Section 4.5 of the SmPC lists medicines which may lead to potentially significant interactions with Paxlovid, and where Paxlovid should be considered only if the benefits outweigh the risks. Healthcare professionals must review these sections of the SmPC in detail before prescribing Paxlovid.
The risks of potential drug interactions when taking Paxlovid, and what actions to take if an adverse event occurs, should be explained to patients by the prescriber. Paxlovid is also contraindicated in patients with hypersensitivities to nirmatrelvir, ritonavir or any of the listed excipients, and in patients with severe renal and/or hepatic impairment. Patients should be reminded to read the Patient Information Leaflet (PIL) and speak to a healthcare professional if they have questions.
Advice for healthcare professionals:
- There is a risk of potentially serious drug interactions with the ritonavir component of Paxlovid leading to increased toxicity from, or reduced effectiveness of concomitant medications.
- Ritonavir is a potent CYP3A4 inhibitor that acts to boost the plasma levels of the nirmatrelvir component of Paxlovid by preventing its degradation; as many commonly used drugs are metabolised by CYP3A4, the risk of harmful drug interactions with Paxlovid is significant.
- Drug interactions may also reduce the effectiveness of Paxlovid, in the treatment of COVID-19.
- Obtain a thorough history of patients’ current medications, including over-the-counter medications, herbal remedies and illicit or recreational drug use.
- Refer to the Paxlovid SmPC before prescribing Paxlovid to check for contraindications and potential interactions.
- Remind patients to read the PIL and to be vigilant for any adverse reactions, seeking medical advice when required.
Please refer to the following website in MHRA for details:
http://www.gov.uk/drug-safety-update/nirmatrelvir-ritonavir-paxlovidv-be-alert-to-the-risk-of-drug-interactions-with-ritonavir
In Hong Kong, Paxlovid Tablets (HK-67360) and Paxlovid Tablets (HK-67683) are pharmaceutical products registered by Pfizer Corporation Hong Kong Limited. Both products are prescription-only medicines. So far, with regard to nirmatrelvir and ritonavir/Paxlovid, the Department of Health (DH) has received 95 cases of adverse drug reaction, of which one case was reported as drug interaction. The current product insert of the above locally registered Paxlovid products include safety information on drug interactions (including a listing of established and other potentially significant drug interactions). The DH will remain vigilant on safety update of the drugs issued by other overseas drug regulatory authorities.
Ends/Friday, Nov 24, 2023
Issued at HKT 15:30
|
| |
|
