Invokana is an oral medication made by Janssen Pharmaceuticals (a division of Johnson & Johnson) prescribed for patients suffering from Type 2 diabetes. The drug is intended to help patients reduce blood sugar levels by encouraging the body to filter out more glucose from the blood and excrete it via urine.
The drug was first introduced into the UK in 2013, with the National Institute for Health and Care Excellence (NICE) publishing final guidance on the drug during 2016.
Whilst still currently available within the UK, Invokana has been the subject of a series of medical safety alerts in the US. These alerts have focussed on the increased risk of lower limb amputations suffered by patients using the medication: More recently, on August 29, 2018, the US regulatory body, the Food and Drug Administration (FDA) also identified canagliflozin, the generic name for Invokana, as raising the risk of patients suffering an infection of the genitals and the area around the genitals. This condition, which is considered rare, is referred to by specialists as Fournier’s Gangrene (also known as necrotizing fasciitis of the perineum). This rare condition is caused by an infection in and around the genitals in both males and females, and can be fatal.
Consequently, Invokana has been the subject of increased scrutiny by the FDA in recent years. In May 2017 the FDA instituted a ‘Black Box Warning’ for Ivokana, compelling the manufacturer of the drug Janssen, a subsidiary of Johnson & Johnson, to ensure that the labelling and packaging of the drug emphasised to all users that by taking the drug they were potentially increasing their risk of leg and foot amputations.
Users of Invokana in the US
The Invokana ‘Black Box Warning’ is now shown clearly on the packaging of the product when it is sold in the US in the format shown below:
Users of Invokana in the UK
Invokana is still widely prescribed and used in the UK. Whilst the Patient Information Leaflet provided to UK patients prescribed Invokana also provides some information about increased amputation risk, this is much less prominent: In contrast to the FDA’s ‘Black Box Warning’ approach UK patients currently receive the following small text warning under a long list of other ‘Warnings and Precautions’:
[Source: eMC ]
A doubling of risk
Data published by the FDA in 2017, from two clinical trials showed that leg and foot amputations occurred about twice as often in patients treated with canagliflozin, the generic name for Invokana, compared to patients treated with a placebo.
Amputations of the toe and middle of the foot were the most common; however, amputations involving the leg, below and above the knee, also occurred. Some patients had more than one amputation, some involving both limbs.
Sources indicate that Invokana litigation is now well advanced in the US, with trials scheduled to begin during autumn 2018. Some sources indicate that settlement negotiations between the manufacturer and claimants are currently underway. Further updates will follow.