The four non-stimulant options
Atomoxetine (Strattera)
- Mechanism: Selective norepinephrine reuptake inhibitor
- Duration: 24-hour coverage
- Onset: 4-8 weeks for full effect
- Best for: Adults who can’t take stimulants, anxiety + ADHD, substance use history
- Side effects: Nausea, sleep changes, sometimes mood, rare hepatic effects
- Effect size: Moderate
Guanfacine (Intuniv)
- Mechanism: Alpha-2 adrenergic agonist
- Duration: 24-hour coverage
- Onset: Weeks for full effect
- Best for: RSD, emotional dysregulation, ADHD + tics, ADHD + anxiety, augmenting stimulants
- Side effects: Sedation, hypotension, dizziness, fatigue
- Effect size: Moderate; particularly strong for emotional features
Clonidine (Kapvay)
- Mechanism: Alpha-2 adrenergic agonist (similar to guanfacine but different receptor subtypes)
- Duration: Variable; immediate and extended release
- Best for: Sleep difficulties, hyperactive ADHD, tic disorders, often as add-on
- Side effects: Sedation, hypotension, dizziness
- Effect size: Moderate
Bupropion (Wellbutrin)
- Mechanism: Norepinephrine and dopamine reuptake inhibitor
- Status: Off-label for ADHD (FDA-approved for depression and smoking cessation)
- Best for: ADHD + depression, ADHD + nicotine cessation, adults who want stimulant-like effect without controlled substance
- Side effects: Anxiety, insomnia, dry mouth, lower seizure threshold (contraindicated in some adults)
- Effect size: Smaller than stimulants but real
When non-stimulants are preferred
- History of substance use disorder
- Cardiac concerns making stimulants risky
- Anxiety amplification on stimulants
- Stimulant side effects intolerable
- Hypersensitive nervous system
- Need for 24-hour coverage without peaks and troughs
- Specific co-occurring conditions (tics, depression)
- Augmenting stimulants for fuller coverage
Combining stimulant + non-stimulant
Common practice. Most common combinations:
- Stimulant + guanfacine: Stimulant for attention, guanfacine for RSD and emotional regulation
- Stimulant + atomoxetine: Less common but used for fuller 24-hour coverage
- Stimulant + bupropion: Possible with cardiac monitoring; addresses depression alongside ADHD
The slower onset reality
Stimulants work acutely — you feel it within hours. Non-stimulants build up over weeks. This requires patience during initial trial:
- Atomoxetine: 4-8 weeks for full effect
- Guanfacine: weeks for full effect, more gradual onset
- Bupropion: 2-4 weeks typically
The slower onset means dose-finding takes longer. But also no rebound, no peak-trough variability, smoother experience day to day.
Side effect comparisons
Sedation
Guanfacine and clonidine often produce sedation, particularly initial doses. Sometimes useful for sleep. Atomoxetine and bupropion generally not sedating.
Anxiety
Bupropion can increase anxiety. Atomoxetine sometimes affects mood. Guanfacine generally reduces anxiety. Choosing based on anxiety baseline matters.
Sleep
Atomoxetine can affect sleep variably. Bupropion often worsens sleep. Guanfacine and clonidine often improve sleep. Timing of dose matters.
Cardiac
Guanfacine and clonidine lower blood pressure. Bupropion can raise it. Atomoxetine can raise heart rate. All require some cardiac monitoring in adults with cardiac history.
How prescribers choose
- RSD or emotional dysregulation prominent → guanfacine
- Anxiety + ADHD → atomoxetine or guanfacine
- Depression + ADHD → bupropion
- Substance use history → non-stimulant generally
- Sleep difficulty + ADHD → guanfacine or clonidine
- Tics + ADHD → guanfacine or clonidine
- Want stimulant-like effect without controlled status → bupropion
FAQ
What non-stimulant ADHD medications exist?
Four main options: atomoxetine (Strattera), guanfacine (Intuniv), clonidine (Kapvay), and bupropion (Wellbutrin — off-label for ADHD). Each works on different neurotransmitter systems and has different profile. Generally smaller effect than stimulants but no controlled substance designation, less abuse potential, useful for adults who can’t take or tolerate stimulants.
Who needs non-stimulant medication?
Adults for whom stimulants don’t work or aren’t appropriate. Reasons: history of substance use disorder making stimulants risky, cardiac concerns, anxiety amplification on stimulants, side effects intolerable on stimulants, hypersensitive nervous system, augmenting stimulants for fuller coverage, specific co-occurring conditions where non-stimulant has dual benefit (guanfacine + tics, bupropion + depression).
Are non-stimulants weaker than stimulants?
Generally smaller effect sizes. In adults, stimulants run roughly 0.5–0.8; non-stimulants around 0.45–0.5 (moderate). But: smaller doesn’t mean ineffective. Many adults respond well to non-stimulants. And the smaller effect comes with different benefits — sustained 24-hour coverage, no rebound, no controlled substance status, often complementary side effect profile.
How do non-stimulants work differently?
Atomoxetine: blocks norepinephrine reuptake. Slow build-up (weeks). 24-hour coverage. Guanfacine and clonidine: alpha-2 adrenergic agonists. Affect norepinephrine signalling differently. Often help with emotional regulation and sleep. Bupropion: norepinephrine and dopamine reuptake inhibitor. Closest mechanistically to stimulants among non-stimulants. Different mechanisms produce different clinical effects.
How long do non-stimulants take to work?
Atomoxetine: 4-8 weeks for full effect. Patience needed. Guanfacine: weeks for full effect, more gradual onset. Bupropion: 2-4 weeks typically. Different from stimulants (acute effect within hours). The slower onset means longer dose-finding process but also no rebound or peak-trough variability.
Can I take stimulant and non-stimulant together?
Yes, common practice. Guanfacine + stimulant is particularly common — guanfacine addresses RSD and emotional regulation; stimulant addresses attention. Atomoxetine + stimulant less common but used. Bupropion + stimulant possible but cardiac considerations. Combination therapy expanded the options for adults who don’t get full benefit from monotherapy.
What about side effects?
Variable by medication. Atomoxetine: nausea, sleep changes, sometimes mood effects, rare hepatic effects. Guanfacine: sedation, hypotension, dizziness, fatigue. Clonidine: similar to guanfacine. Bupropion: anxiety, insomnia, dry mouth, lower seizure threshold (contraindicated in some adults). Generally well-tolerated but trial-and-error to find the right fit.
Are non-stimulants right for women in pregnancy?
Limited pregnancy data for atomoxetine. Bupropion has more pregnancy data than atomoxetine, but it remains limited and mixed — not a reason to assume it is safer. Guanfacine and clonidine have specific pregnancy considerations (blood pressure effects). For specific medication-and-pregnancy decisions, see our adhd-medication-pregnancy guide and discuss with prescriber. Pregnancy decisions are individual.