Accepted answer
Timing is the most useful diagnostic feature here and it is the one most often omitted from the question.
Pancreatitis red flags worth memorising rather than looking up: severe, persistent epigastric pain radiating to the back, worse lying flat and better sitting forward, with nausea and vomiting that does not settle. That combination is an urgent assessment, not a dose adjustment. An isolated lipase elevation without that picture is common and usually not pancreatitis.
Local reaction versus infection
| Feature | Local reaction | Sterile abscess | Cellulitis |
|---|
| Onset | Hours to 2 days | Days | 1–4 days, progressive |
| Warmth | Absent or minimal | Mild | Marked |
| Expansion | Static or shrinking | Slow | Expanding |
| Texture | Firm, flat or raised | Fluctuant | Diffuse, indurated |
| Systemic features | None | None | Fever, malaise possible |
| Action | Observe, rotate site | Clinical review | Same-day clinical review |
The relevant detail is that fatigue attribution is a subtraction problem. Take out the energy deficit, the dehydration, the electrolyte shortfall and the poor sleep, and what remains attributable to the drug in the trials was modest — placebo-arm fatigue rates were within a few points of active-arm rates in most of the programme. The corollary is that the fixable causes are usually the actual causes.
The prescribing information for each agent lists adverse reaction frequencies against placebo in a table, and reading that table is more informative than reading a hundred anecdotes, because it has a denominator.
Write down in advance which symptoms mean stop and seek care. It is a short list and it is much easier to write when you are well.
edited 7 Sept 2025 by sian_llewellyn — tightened the wording; no substantive change