Week 2 is day 14: on a four-week ladder that is week 2 of dose step 1, and — at the seven-day half-life this class runs on — 2 half-lives in. Steady state is about five half-lives, so day 35 is where the concentration stops climbing on its own. Day 14 is 3 weeks short of it, so the level is still rising even though the dose has not changed. That distinction is most of the question: at week 2 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. Constipation is the one that does not follow the escalation curve. It builds with cumulative exposure and with the fall in food and fluid volume, so it characteristically appears later than nausea and outlasts it by months. Dose decisions are made under supervision, and nothing here is medical advice.
Stated carefully, this is the adverse effect that persists longest, because unlike nausea it does not attenuate with tolerance.
Soluble fibre — psyllium, oats, legumes — holds water and softens stool. Insoluble fibre adds bulk and speeds transit. In slowed-transit constipation the soluble kind is generally the more useful of the two.
Gastrointestinal adverse events, indicative pooled rates
| Event | Active arm | Placebo arm | Timing |
|---|
| Nausea | 40–45 % | 15–20 % | Peaks 1–2 wk after each step |
| Vomiting | 15–25 % | 5–8 % | Follows nausea |
| Diarrhoea | 20–30 % | 10–15 % | Early, variable |
| Constipation | 20–25 % | 8–12 % | Later onset, persistent |
| Discontinuation for GI events | 4–7 % | 1–2 % | Mostly during escalation |
Ranges span agents and doses; read the specific prescribing information for a specific figure.
Aim for 25 to 30 grams of fibre a day, which requires deliberate planning at a reduced total intake because fibre-rich foods are bulky and satiating exactly when appetite is suppressed.
Osmotic first, stimulant reluctantly, and not as a standing arrangement.