Exclusive: Over 300 Yellow Card reports of people who have experienced an altered sense of taste while taking the antiviral Paxlovid have been received by the Medicines and Healthcare products Regulatory Agency (MHRA).

In a statement, shared with The Pharmacist today (6 June), the MHRA said it has received 326 UK Yellow Card reports of different taste disorders, all of which were suspected to be associated with Paxlovid.

It said that 314 of the 326 reports relating to Paxlovid sent to the MHRA were for ‘dysphasia’, in which people experience a sour, sweet, bitter, or metallic taste.

A further 11 reports were for ‘ageusia’: the complete loss of taste.

Meanwhile, the medicines watchdog also received one report of ‘hypogeusia’, the reduced ability to taste things.

Since April, people over 50 in England who test positive for Covid-19 have been eligible to receive Paxlovid through the PANORAMIC trial, with 11,594 having been prescribed the drug so far.

While the MHRA said that all the taste disorders were ‘suspected to be associated with Paxlovid’ it also acknowledged that taste disorder is also ‘associated with Covid infection’.

‘[An altered sense of taste] is a recognised adverse effect of Paxlovid listed in the patient information leaflet and may affect up to 1 in 10 people who take it,’ it said.

Paxlovid, manufactured by Pfizer, has been found to reduce the relative risk of Covid-19-associated hospitalisation or death by 88% in those who received treatment within five days of developing symptoms.

According to data from Pfizer's clinical trials of the antiviral, about 6% of participants in the Paxlovid group experienced the altered taste, compared to less than 1% of those in the placebo group.

A report of a suspected side effect to the Yellow Card scheme does not necessarily mean that it was caused by the treatment, only that the reporter has a suspicion that it may have been.