That's a reasonable description of some common concerns with covalent drugs, but to say that they haven't had much impact in the clinic is misleading. See, for

That's a reasonable description of some common concerns with covalent drugs, but to say that they haven't had much impact in the clinic is misleading. See, for example * Beta lactam antibiotics (e.g. penicillin) * Aspirin * Prilosec And there are plenty of others. Many companies do tend to avoid them, but one could reasonably argue that their reputation is undeserved.