FOI release

Freedom of Information request on tenofovir disoproxil and emtricitabine causing lactic acidosis (FOI 21/696)

Published 29 December 2021

20th July 2021

FOI 21/696

Dear

Thank you for your FOI request dated 22nd June 2021, where you requested the following information:

I am looking for some more information regarding tenofovir disoproxil and emtricitabine causing lactic acidosis. I can see from the Drug Analysis Prints there are 15 reports. I just wondered if you are able to provide further details on them?

Yellow Card data is releasable to members of the public provided that patient and reporter confidentiality is maintained. Under the Freedom of Information Act (FOIA) 2000, the data for this request has been provided as category 1b. For this FOI, the line listing contains the following fields:

• Patient age categories (as aggregated data)
• Patient gender categories (as aggregated data)
• Suspect drug(s)
• Drug dose
• Route of administration
• Suspected adverse drug reaction(s)
• Adverse drug reaction outcome(s)
• Time to onset
• Past medical history

I can confirm that as of the 05/07/2021 the MHRA has received no UK suspected spontaneous adverse drug reaction (ADR) reports concerning lactic acidosis in association with emtricitabine and tenofovir used in combination. However, the MHRA has received 15 UK spontaneous suspected ADR reports of lactic acidosis in association with tenofovir and 1 additional ADR report in association with emtricitabine.

As requested, please see attached tables including a breakdown of the 15 UK spontaneous suspected ADR reports of lactic acidosis associated with products containing tenofovir. The information is presented in a line listing (Table 1), and aggregated patient age and sex (Tables 1a and 1b). Please note, any blank cells within the tables are fields which have not been provided to us.

Please note that the provision of category 1b data depends on the number of cases held by the Agency. As mentioned above, the MHRA will not release any data subset in which there are five or fewer cases as this is necessary to prevent identification of patients and/or reporters. As such, we are unable to provide category 1b data for the one report of emtricitabine in association with lactic acidosis. Please see the case summary below:

Case summary: This case relates to a male patient who experienced lactic acidosis after taking Descovy. At the time of reporting, these reactions had not recovered.

It is important to note that an ADR report is not proof of a side effect occurring, but a suspicion by the reporter that the drug may have caused the side effect. The fact that symptoms occur after a drug is given does not mean that they are caused by the drug itself as underlying or undiagnosed illnesses and other factors may be responsible.

Furthermore, the number of reports received via the Yellow Card Scheme does not directly equate to the number of people who suffer adverse reactions to drugs for a number of reasons. ADR reporting rates may be influenced by the seriousness of reactions, their ease of recognition, extent of use of a particular drug or vaccine and promotion and publicity about a drug/vaccine.

I hope the information provided is helpful. The MHRA encourages the use of Yellow Card data however wishes to ensure that the data is studied and applied appropriately, and any conclusions/interpretations take into account the above information. For this reason, if you wish to use this information for a publication, we request that you engage with the MHRA during this process and provide a copy of the report. If you are dissatisfied with the handling of your request, you have the right to ask for an internal review. Internal review requests should be submitted within two months of the date of this response; and can be addressed to this email address.

Yours sincerely,

FOI Team,

Vigilance and Risk Management of Medicines Division