Most people starting an ADHD medication will get some side effects in the first 1–2 weeks. Most of those side effects fade as your body adjusts. A small number don't — and a smaller number need urgent attention. This guide is about telling those categories apart and logging them in a way your prescriber can actually use.
How to log a side effect in five seconds
Three pieces of information per entry:
- What — short keyword. "Dry mouth," "appetite," "jaw clenching."
- How bad — mild / moderate / severe (or 1–3).
- When — only if it has a clear pattern. "Mornings only," "around 4pm," "all day."
That's it. Don't try to write a novel. Patterns emerge over weeks of brief entries, not from one detailed paragraph.
Common side effects on stimulants — and what they usually mean
Appetite suppression
Almost everyone gets some. Typical pattern: appetite low or absent during peak medication hours, returns in the evening as the dose wears off. Worth logging the time-window ("no appetite until 5pm").
When to flag it: if you're losing weight unintentionally, if you can't get adequate calories in (especially in children), or if it isn't improving after 2–3 weeks. Practical workarounds — eating before the dose kicks in, calorie-dense evening meal — are worth discussing with your prescriber.
Sleep onset trouble
Common with stimulants taken too late in the day, with longer-acting formulations, or at higher doses. If you can't fall asleep until 1–2am on dosing days but sleep fine on days off, the medication is the cause.
Useful log: time you went to bed, time you actually fell asleep, total sleep hours.
Dry mouth
Very common, usually mild. Worth flagging if it's contributing to dental problems (water intake helps; sugar-free gum helps).
Jaw clenching / teeth grinding (bruxism)
Worth tracking the frequency and whether it's during the day or at night. Persistent bruxism on stimulants sometimes resolves with a small dose reduction or a switch to a different medication.
Mid-afternoon "crash"
A noticeable drop in focus, energy, or mood as the medication wears off. Pattern: you feel fine through the active period, then suddenly tired, irritable, or mentally fogged. Different from a steady taper.
Worth logging the time the crash hits — it directly informs dose timing and formulation choices (longer-acting, split dose, booster, etc.).
Anxiety or restlessness
Mild jitteriness in the first 1–2 weeks is common and usually settles. Worth flagging if it's significantly affecting your life or if it isn't improving by week 3.
Mood flatness or "emotional blunting"
Sometimes reported on stimulants — feeling functional but emotionally muted. Track this carefully; it's hard to notice from the inside, but partners or close colleagues sometimes notice it before you do.
Cardiovascular: racing heart, palpitations
Worth logging carefully. A modest, steady heart-rate increase is expected on stimulants. Frequent palpitations, racing heart at rest, chest discomfort, or shortness of breath should be flagged urgently.
Common side effects on non-stimulants
If you're on atomoxetine (Strattera), viloxazine (Qelbree), guanfacine, clonidine, or bupropion (Wellbutrin), the side effect profile is different:
- Atomoxetine / viloxazine: daytime sleepiness, GI upset, decreased appetite, sometimes liver-enzyme changes (your prescriber may run blood work).
- Guanfacine / clonidine: sedation, low blood pressure (dizziness on standing), dry mouth, sometimes mood changes.
- Bupropion: insomnia, dry mouth, headache, lower seizure threshold (relevant if you have a seizure history or eating disorder).
Many non-stimulant side effects are dose-dependent and time-of-day-dependent. Logging when you took the dose vs when the side effect appeared is more important here than with short-acting stimulants.
What usually fades vs. what usually doesn't
Usually fades over 1–2 weeks: initial nausea, mild anxiety, mild insomnia, headaches, mild appetite suppression. If these are tolerable, hold and re-evaluate at 2 weeks.
Usually persists if not addressed: ongoing sleep onset problems, persistent jaw clenching, persistent appetite loss with weight change, mood blunting, sustained anxiety. These often need a dose change, timing change, or medication switch — bring them up at your follow-up.
When to call your prescriber sooner rather than waiting
Some side effects are urgent. Call your prescribing clinician (or use an urgent care channel if you can't reach them):
- Chest pain, severe palpitations, fainting, or shortness of breath.
- New or significantly worsening anxiety, depression, mood swings, or thoughts of self-harm.
- Hallucinations, paranoia, or confusion (rare but serious — more often at higher doses).
- Severe allergic reaction (rash, swelling, difficulty breathing).
- Persistent severe headache, vision changes, or sudden numbness.
- Significant unintended weight loss (especially in children).
- Yellowing of the skin or eyes (atomoxetine).
This list is not exhaustive — when in doubt, call.
What to bring to your visit
Print the side-effects column from your tracker. Highlight any side effect that hasn't faded by week 2–3, anything that's interfering with your sleep or eating, and anything new since the last dose change. Bring 1–2 specific examples ("Tuesday I couldn't fall asleep until 2am after my afternoon dose") instead of generalizations.