not that I've found in some more searching. However to me this indicates either
- not only is a narrow theraputic range, it has a narrow theraputic effect, suggesting that it is well understood and relatively simple (unlike many drugs which were developed for X and testing found that they do Y Z and a few other tricks too)
- nobody has been interested in it for the last 30 years, instead focusing their efforts in demonstrating the efficacy of their own developed poisons which cost far more
Lastly a clue to this is found in the following:
https://www.nps.org.au/australian-prescriber/articles/warfarin-balancing-the-benefits-and-harms
Anticoagulation with warfarin significantly reduces the morbidity and mortality related to arterial and venous thromboembolism. For many patients the benefit is clear and the risk of harm is acceptable, so anticoagulation is indicated.
Almost 1.9 million out-of-hospital prescriptions for warfarin were dispensed in 2001.The cost to the Pharmaceutical Benefits Scheme (PBS) and Repatriation Pharmaceutical Benefits Scheme (RPBS) of warfarin for the same period was $8.3 million. From Health Insurance Commission statistics coagulation tests numbered 2.5 million in the same year at a cost of $29.4 million. Most of these tests are for routine monitoring of warfarin therapy. There are therefore many patients taking warfarin, but the decision to use the drug and accept the adverse effects requires constant review.
not that I'd suggest that drug companies want to take that revenue away from Labs ... or indeed to go further and say Labs don't want to lose that to Coacucheck-alike devices (and drop that cost to society by probably a factor of 10 or more).