Just to add additional details:
Despite the market withdrawal, Health Canada also announced that patients can maintain the use of the drug as prescribed, although it is necessary to consult a doctor about other treatment options.
Interestingly, studies described in the literature indicate that the compound N-nitroso-propanolol does not present mutagenic potential when evaluated in an ames test in several strains or mutagenesis assay in mammalian cells, and that thus, it would be unlikely that this structure was carcinogenic.
Last year @fernandaw presented at USP-Sindusfarma Nitrosamine Workshop a case study on Nitroso-Atenolol Nitrosamine Workshop USP / Sindusfarma / ANF ACFB -live discussion - #8 by Naiffer_Host You can watch the recording in the link (1:38:07).
On the other hand, when evaluated by in vivo micronucleus assays in rats, N-nitroso-propanolol was able to present a slight increase in micronucleated cells in the liver, but did not exert the same clastogenic effects in bone marrow and spleen.
These data make the evaluation of the mutagenic and carcinogenic potential of N-nitroso-propanolol controversial and complex.
@fernandaw / @chakravarti_suman / @kpcross / @David Do you have any additional insight from your assessment to share?