Not in this case; the main effect of deuteration is to slow the rate at which the active drug is metabolized and excreted. Now, that might not sound significan

Not in this case; the main effect of deuteration is to slow the rate at which the active drug is metabolized and excreted. Now, that might not sound significant — but patient compliance with medication regimes is a significant sticking point in clinical practice; people are generally just terrible about taking their meds on schedule. If you can replace a twice-a-day tablet with a once-a-day treatment, that's a big win for the subset of patients who are forgetful/unreliable at taking their meds twice a day — and in a disease where the symptoms progress to dementia, that's important. More on medication compliance here (some of it quite hair-raising): https://en.wikipedia.org/wiki/Adherence_(medicine) https://en.wikipedia.org/wiki/Adherence_(medicine)