Toxic epidermal necrolysis induced by Lansoprazole: pharmacologic considerations.

I would like to make some comments about the report entitled "Toxic epidermal necrolysis induced by lansoprazole," published by Fracaroli et al. in 2013.[1] I also aim to add some recent evidence about the growing and alarming incidence of adverse drug reactions (ADR) after the use of proton pump inhibitors (PPIs) to this relevant article.

Some authors attribute this phenomenon to the current popularity of these drugs in both hospitals and outpatient enviroments.[2] Some evidence also points to possible under-notification of the reactions caused by PPIs, as they are wrongly regarded as symptomatic drugs and routinely prescribed in combination with other compounds.[3]

Little is known about the immunopathological mechanism of these reactions; however, a diverse spectra of Gel and Coombs classification have been described.[2] It is important to mention that the metabolism of PPIs results in the formation of the active compounds sulfenic acids and sulfonamide.[2] Omeprazole, the most widely used PPI, is a subject of frequent discussion regarding its potential to generate cross-reaction with classic sulfonamides. Cross-reactivity between the different PPIs is also known.[4]

Restrictions on the use of medications with possible cross-reaction with sulphonamides are controversial. However, one must be careful in the case of patients with proven sensitivity to drugs such as sulfadiazine and sulfamethoxazole.[2,5] In addition, the PPIs should not be prescribed as simple symptomatic medicine to patients who have already developed ADR.

Drug metabolism and possible cross-reactions should always be considered, especially in the case of known hypersensitivity and potential severe ADR.