Accepted answer
Week 12 is day 84: on a four-week ladder that is week 4 of dose step 3, and — at the seven-day half-life this class runs on — 12 half-lives in. Steady state is about five half-lives, so day 35 is where the concentration stops climbing on its own. Day 84 is 7 weeks past it, which means the level is no longer the variable. That distinction is most of the question: at week 4 of a step, an effect that is still accumulating is indistinguishable from one that is not resolving unless you know which side of day 35 you are on. Vomiting is the rarer and more informative of the pair. It follows the same escalation weeks as nausea, so one arriving well away from a step is pointing at something other than the ladder. Dose decisions are made under supervision, and nothing here is medical advice.
Answer first: vomiting is less common than nausea, is more strongly dose-related, and matters chiefly because of what it does to fluid and electrolyte balance.
Dental enamel erosion from repeated vomiting is a real if unglamorous consequence; rinsing with water rather than brushing immediately is the standard advice.
In practice, oral rehydration solutions work by glucose-coupled sodium co-transport, which continues to function when secretion is deranged. That is why the glucose-to-sodium ratio matters and a high-sugar sports drink is not equivalent.
Vomiting rates in the trial programmes are reported separately from nausea and are consistently lower and more dose-dependent.
Anti-emetics interact with other medication and are a prescriber decision.
Small frequent sips of an oral rehydration solution, not large volumes of water.
edited 26 May 2025 by Dr_Lena_Ostrowska — removed a claim I could not source