ADHDnotepad
Medication guide

Atomoxetine (Strattera)

Atomoxetine hydrochloride

Atomoxetine is a non-stimulant ADHD medicine for children and adults. Benefit develops over weeks with regular daily treatment. This guide explains dosing, what to expect, side effects and when to get help.

Non-stimulantNot a controlled drugOnce daily24-hour coverage

Written and clinically reviewed by ADHD Advanced Practitioner and Clinical Prescribing Pharmacist

Reading time: about 9 minutesLast reviewed: Next review: Download the one-page summary (PDF)

Atomoxetine (Strattera): key facts

What it is
A once-daily non-stimulant capsule for adult ADHD. It is NOT a stimulant and NOT a controlled drug. It works by gradually building up the brain's noradrenaline levels: giving you steady, 24-hour coverage.
How to take it
Once a day at the same time, or split into two doses if your prescriber advises. Swallow each capsule whole: do not open, crush, or chew it. It can be taken with or without food.
When it starts working
Gradually over weeks: not hours or days. About half of people who will respond notice their first real improvement at around 3–4 weeks. Most of the benefit is visible by week 12.
Most common early effects
Nausea (especially in the first couple of weeks), reduced appetite, dry mouth. Most settle on their own as your body adjusts.
When to get urgent help
Severe allergic reaction, signs of a stroke or a first seizure → call 999. Erection lasting more than 2 hours → A&E immediately. Yellow skin or eyes → stop and contact your prescriber. New thoughts of self-harm → contact your care team today (call 999 if you might act on them).
Not a controlled drug
No special prescription needed. Your GP can prescribe it on a standard repeat prescription.
Section 1

What is atomoxetine?

Atomoxetine is the only non-stimulant licensed specifically for ADHD in UK adults. It is often used when stimulants have not worked or are not suitable, and it has positive evidence when anxiety and ADHD occur together.

Atomoxetine (Strattera) at a glance

Atomoxetine (Strattera): key facts at a glance, each with its source
FactDetail
Active ingredientAtomoxetine hydrochloride: a selective noradrenaline reuptake inhibitorSource: Atomoxetine 25 mg hard capsules SmPC (Zentiva, eMC)
Medicine typeNon-stimulant capsule, once daily. Not a controlled drugSource: BNF: atomoxetine
Strengths10, 18, 25, 40, 60, 80 and 100 mg capsules; oral solution 4 mg/mLSource: Atomoxetine SmPCs on eMC, all strengths
Usual starting dose (adults)40 mg once a day for at least 7 daysSource: Atomoxetine 25 mg hard capsules SmPC (Zentiva, eMC)
Usual maintenance dose80 to 100 mg a day (adults)Source: Atomoxetine 25 mg hard capsules SmPC (Zentiva, eMC)
Maximum licensed dose100 mg a daySource: Atomoxetine 25 mg hard capsules SmPC (Zentiva, eMC)
When it starts to workFirst improvements at around 3–4 weeks; most of the benefit by week 12
FoodWith or without food. Taking it with a meal can ease early nauseaSource: Atomoxetine 25 mg hard capsules SmPC (Zentiva, eMC)
How to take itSwallow whole. Never open, crush or chew the capsuleSource: Atomoxetine 25 mg hard capsules SmPC (Zentiva, eMC)

When it's prescribed

Often recommended when stimulants have not worked or aren't suitable: or when a non-controlled-drug option is preferred. Also has positive evidence in ADHD with anxiety.

Typical duration

24 hours, once your body reaches steady state (usually after 1–2 weeks of daily use). No on/off effect. No rebound in the evening.

Pros of atomoxetine

  • NOT a stimulant: completely different mechanism from methylphenidate or Elvanse
  • NOT a controlled drug: standard repeat prescription from your GP
  • 24-hour steady coverage: no gap in the afternoon or evening, no rebound
  • Works overnight too: no ADHD symptom 'holiday' at the weekend
  • Low misuse potential: it did not act like a stimulant in abuse-potential studies
  • Positive evidence when anxiety and ADHD occur together
  • Better sleep profile than most stimulants: less likely to affect your ability to get to sleep
  • No positive result on standard workplace or forensic drug tests

Cons of atomoxetine

  • Takes weeks to work; this is not a medication you'll feel kicking in on day one
  • Must be taken every day; it doesn't work 'as needed'
  • Capsules must be swallowed whole: do NOT open them (the powder is an irritant)
  • GI side effects (nausea, dry mouth, reduced appetite) are common at the start
  • Blood pressure and heart rate are monitored throughout treatment
  • Check your other medications: some antidepressants (especially fluoxetine and paroxetine) interact with atomoxetine and need a dose adjustment
Section 2

How does atomoxetine work?

Atomoxetine blocks the noradrenaline transporter, so noradrenaline and dopamine build up in the prefrontal cortex. This happens gradually, which is why it takes weeks rather than hours to work.

When you have ADHD, two key brain chemicals: noradrenaline and dopamine: aren't doing their job properly in the part of your brain that handles focus, planning, and impulse control (called the prefrontal cortex).

Atomoxetine targets a specific transporter called the NET: the noradrenaline transporter. Think of the NET as a vacuum cleaner that removes noradrenaline from the synapse as soon as it's released. Atomoxetine blocks the vacuum. Noradrenaline builds up, stays in the synapse longer, and starts to reach levels that actually support your brain's executive function.

The same transporter happens to carry dopamine too, in the prefrontal cortex. So by blocking the NET, atomoxetine also raises dopamine levels in that region: even though it has no direct effect on dopamine pathways. This is why it helps with the full range of ADHD symptoms, not just one aspect.

Why does it take so long? Stimulants work by flooding the synapse immediately; you feel them within an hour. Atomoxetine doesn't do that. It works by gradually shifting the baseline level of noradrenaline. That shift takes time. The receptor system in the prefrontal cortex needs to adapt to the new level. This is not a sign the medication isn't working. It is how it works. The effect is building even when you can't feel it yet.

Once atomoxetine reaches steady state in your blood (after 1–2 weeks of daily dosing), it maintains a stable level all day and all night. There is no 'window' when it's active and a window when it isn't. You won't feel it switch off at 6pm.

What atomoxetine doesn't do: it has no stimulant effects; it doesn't cause a 'high' or euphoria; it doesn't affect dopamine in the reward pathways (striatum): only in the prefrontal cortex; it has no serotonin activity; it won't cause a positive result on a drug test for stimulants or any other controlled substance.

How atomoxetine works: visual guide

Follow atomoxetine from capsule to steady effect. Use ADHDnotepad's animated visual medication journey to see how this non-stimulant builds up with daily dosing and blocks noradrenaline reuptake in the prefrontal cortex, without directly targeting dopamine, giving calmer, more consistent focus across the whole day.

ClinicalDeeper clinical detail

Atomoxetine is a selective noradrenaline reuptake inhibitor (SNRI): distinct from the SNRI antidepressants (which also act on serotonin). It has high selectivity for the noradrenaline transporter (NET) with minimal affinity for the dopamine transporter, serotonin transporter, or other neurotransmitter receptors.

Mechanism: Selective NET blockade in the prefrontal cortex (PFC) increases extracellular noradrenaline and, secondarily, dopamine (via NET-mediated dopamine reuptake in PFC, where DAT expression is low). This enhances α2A-adrenoceptor signalling in the PFC: directly improving working memory, inhibitory control, and attentional networks.

Pharmacokinetics: Primarily metabolised by CYP2D6 to 4-hydroxyatomoxetine (active, similar potency). In extensive metabolisers (EM): half-life ~5 hours. In poor metabolisers (PM, ~7% of population): half-life ~22 hours, plasma levels 5–10 times higher. PM status is equivalent clinically to CYP2D6 inhibitor co-administration (e.g. fluoxetine, paroxetine, bupropion).

CYP2D6 interaction: Fluoxetine or paroxetine co-administration inhibits CYP2D6, converting EMs to phenotypic PMs: increasing AUC 5–7 fold. Start at 40mg and titrate cautiously. Dose ceiling is lower in this context.

MAOI contraindication: Absolute. MAOIs + atomoxetine → severe hypertensive crisis risk. 14-day washout from MAOI before starting atomoxetine.

Liver toxicity: Rare cases of severe hepatotoxicity reported post-marketing. Clinically significant jaundice or liver enzyme elevation warrants immediate discontinuation. Do not rechallenge.

Priapism: Rare but documented. Noradrenergic mechanism in erectile tissue. All patients should be counselled at initiation: erection >2 hours = emergency presentation.

AUDS evidence: Positive RCT data for atomoxetine reducing heavy drinking days in adults with comorbid ADHD and alcohol use disorder (AUD). Relevant for shared prescribing decisions.

Section 3

How do I take atomoxetine?

Take your dose once a day at the same time, or split into a morning and a late afternoon or evening dose if your prescriber advises, with or without food. Swallow each capsule whole. Never open a capsule: the powder irritates the eyes, skin and mouth.

Interactive atomoxetine response timeline

See how long atomoxetine may take to work. Use ADHDnotepad's interactive atomoxetine response chart to explore how response builds over weeks rather than hours, compare it with a stimulant, and hover to see published response rates at weeks 4, 12 and 26. The chart is illustrative, as the time to respond varies between people.

When to take it

Once daily, at roughly the same time each morning. Or, if your prescriber has recommended it, split into two doses: one in the morning and one in the late afternoon or evening. Because atomoxetine is not a stimulant, you can take an evening dose without it affecting your sleep. The 24-hour mechanism means that even taking it at different times of day won't cause a late-night stimulant effect.

Taking it with food

You can take atomoxetine with or without food. The total amount absorbed stays the same either way. Taking it with a meal or a snack is recommended: especially at the start: because it can reduce the nausea that some people experience in the early weeks. The meal slightly reduces the peak concentration, which may ease GI side effects without reducing overall effectiveness.

Swallowing the capsule

Swallow the capsule whole with water. Do NOT open, crush, or chew the capsule. This is different from some other ADHD medications (such as Elvanse, which can be opened into water). Atomoxetine capsules contain a powder that can irritate the skin, eyes, and mouth if it comes into contact. If a capsule is accidentally damaged, avoid touching the powder and wash any contact area thoroughly with water. If you cannot swallow capsules at all, tell your prescriber: an oral solution (4mg/mL) is available.

Your dose

Doses are set based on your body weight and how you respond. Adults weighing 70kg or more: Starting dose (for at least 7 days) = 40mg once daily. Standard maintenance = 80mg once daily. Maximum licensed dose = 100mg/day. Adults weighing less than 70kg: Your prescriber will calculate your dose based on your weight. You'll typically start at 0.5mg/kg/day and work up to 1.2mg/kg/day. Dose increases are made at intervals of at least 7–14 days. Don't be tempted to increase faster: your body needs time to adjust at each level.

Missed doses

Take it as soon as you remember: unless it's nearly time for your next dose, in which case skip it and carry on as normal. Never take two doses to make up for a missed one. Occasionally missing a dose won't cause a rebound or crash. But because the medication works by maintaining a steady level, consistent daily dosing gives you the best results.

Do I take it every day: including weekends?

Yes. Atomoxetine needs to be taken every day to maintain its steady-state level. Unlike stimulants, which some people take 'medication holidays' from, atomoxetine doesn't work that way: missing a few days reduces your coverage and can mean it takes time to build back up.

ClinicalPrescribing and clinical detail

Section 4

What should I expect from atomoxetine week by week?

Atomoxetine takes weeks, not days. About half of the people who will respond notice their first real improvement at around 3–4 weeks, and most of the benefit shows by week 12.

Week 1

Medication present, results not yet visible

The medication is in your system from day one. Most people notice little change in ADHD symptoms yet. You may notice side effects: nausea, reduced appetite, dry mouth. These are most prominent now. This is completely normal.

Week 2

Reaching steady state

The medication is reaching steady-state. Some people begin to notice small shifts: slightly less reactive emotionally, a bit more able to follow a thought through. GI side effects usually starting to ease.

Weeks 3–4

First real improvements for most

Around here is when most people who will respond notice their first real improvement. About 47% of eventual responders notice something by week 4. Don't be discouraged if you haven't felt it yet: you're still well within the expected window.

Week 12

Main review point

The main clinical check-in point. By now, around three quarters of eventual responders have responded. If there's no improvement at a therapeutic dose, your prescriber will reassess. If your prescriber is monitoring your response, they may have increased your dose around weeks 6–8 if needed.

Weeks 26–52

Continuing improvement

Improvement often continues well beyond week 12. About 85% of eventual responders have responded by week 26; 96% by week 52. Some people find their full benefit only becomes clear after six months to a year. Keep attending reviews: the picture often keeps getting better.

Section 5

What are the side effects of atomoxetine?

Nausea, reduced appetite and dry mouth are the most common early effects. They usually settle in the first 2–3 weeks as your body adjusts.

All expanded by default: tap a category to collapse it. Most of these ease in the first 1–2 weeks.

Nausea

Very common (about 1 in 4 people in trials)

Most common in the first 1–3 weeks.

Usually settles within 2–3 weeks.

What helps

  • Take your dose with a meal or snack; this reduces the peak concentration and usually helps.
  • Drinking enough water and eating regular, smaller meals may help.

Dry mouth

Very common in adults (about 1 in 5 people in trials)

Usually improves after the first few weeks.

What helps

  • Sip water regularly through the day.
  • Sugar-free gum or mints stimulate saliva.
  • Keep up dental check-ups.
  • Tell your prescriberMention it at your review if it bothers you or is severe.

Reduced appetite

Very common (about 1 in 6 people in trials)

Common at the start, and usually improves.

Your prescriber will monitor your weight at reviews.

What helps

  • Eat well when your appetite is good, often first thing or in the evening.
  • If cooking in the evening feels like too much, prepare food earlier in the day, when you have the energy; ready-to-heat meals (the balanced, freshly made kind) save the planning that stops many people eating.

Constipation

Common (about 1 in 12 people in trials)

What helps

  • Drink enough fluids and eat fibre: fruit, vegetables and wholegrains.
  • Regular, moderate exercise such as a daily walk, cycling, swimming or gardening helps keep your gut moving.
  • Tell your prescriberMention at your next review if persistent.

Stomach pain

Very common in children; common in adults (about 1 in 14 people in trials)

Usually related to the early adjustment period.

What helps

  • Taking with food helps.
  • Tell your prescriberMention at your next review if it doesn't improve.

Insomnia

Very common in adults; common in children (about 1 in 7 people in trials)

Atomoxetine can affect sleep.

Some people have difficulty falling or staying asleep, while others feel sleepy.

  • Tell your prescriberTell your prescriber about the pattern; they may review your dose or dosing schedule. Do not change the schedule yourself.

Fatigue / tiredness

Common (about 1 in 10 people in trials); sleepiness is very common in children

Most common in the early weeks.

For most people it improves once steady state is established.

  • Tell your prescriberIf it persists, mention at your next review.

Raised heart rate

Very common

Mild increases are a direct effect of how this medication works (noradrenaline affects the cardiovascular system).

Your prescriber will check this before you start, after each dose change and at reviews.

What helps

  • Cut down on caffeine and avoid cold and flu remedies that contain a decongestant.
  • Keep salt and alcohol down, and keep up regular moderate exercise.
  • Tell your prescriberTell your prescriber within a few days if your resting pulse stays above 100. The same if your blood pressure stays at 140/90 or higher (135/85 at home).
  • Get help todayA reading of 180/120 or higher after 5 minutes' rest, or a resting pulse above 120: contact your prescriber or 111 today.

Raised blood pressure

Very common

Checked at every review.

  • Tell your prescriberIf you check at home, 140/90 or higher (135/85 at home) counts as high: tell your prescriber within a few days if readings stay there.
  • Get help todayA reading of 180/120 or higher that stays after 5 minutes' rest: contact your prescriber or 111 today.

Palpitations

Common

Brief awareness of your heartbeat can occur.

  • Call 999Call 999 for severe chest pain or chest pain spreading to your arm, jaw or back.
  • Get help todayContact your prescriber the same day for mild chest pain, a racing or irregular heartbeat at rest, or if you feel like you might faint.

Dizziness

Common (about 1 in 12 people in trials)

Usually mild.

What helps

  • Stay hydrated.
  • Don't drive while dizzy.
  • Tell your prescriberMention at your next review if persistent.

Erectile difficulties

Common (about 1 in 12 in trials)

Related to noradrenaline's role in the autonomic nervous system.

Often improves over time.

  • Tell your prescriberDiscuss with your prescriber; you don't have to put up with it.

Difficulty passing urine

Common in adults (about 1 in 17 people in trials); rare in children
  • Tell your prescriberIf urinary symptoms are uncomfortable or not improving, tell your prescriber.

Delayed ejaculation

Common

Often improves over time.

  • Tell your prescriberDiscuss with your prescriber if it's affecting quality of life.

Priapism (erection lasting more than 2 hours)

Rare: but a medical emergency
  • Call 999Go to A&E immediately. Do not wait and see. It doesn't matter whether it is painful or not. Every hour of delay increases the risk of permanent injury.

Irritability

Common (about 1 in 20 people in trials)

Most people find emotional reactivity improves with atomoxetine.

  • Tell your prescriberIf you feel more irritable, note when it happens and mention at your next review.

Suicidal thoughts (warning)

Uncommon (in adult trials, no more common than with placebo: 0.11% vs 0.12%)

Atomoxetine carries a regulatory warning about suicidal thoughts (mainly from paediatric data).

In adults, the trial data shows this was no more common on atomoxetine than placebo.

  • Get help todayIf you experience new or worsening thoughts of self-harm, contact your care team that day: not because atomoxetine is particularly risky in adults, but because any mental health change during medication adjustment should be assessed promptly.
  • Call 999If you feel you might act on these thoughts, or you have harmed yourself, call 999 or go to A&E.

Headache

Very common

Most common early in treatment and often eases.

What helps

  • Drinking enough water and eating regular meals may help.
  • Paracetamol can usually be taken alongside atomoxetine.
  • Check with a pharmacist first if you have other health conditions or take other medicines.

Sweating

Common in adults; uncommon in children
  • Tell your prescriberMention at your next review if it's affecting daily life.

Hot flushes

Common

Usually mild.

  • Tell your prescriberMention at your next review if persistent.

Weight loss

Common

Your prescriber will monitor your weight at reviews.

Raynaud's phenomenon (fingers or toes turning white or blue in cold)

Rare

What helps

  • Keep your hands and feet warm.
  • Avoid handling frozen items without gloves.
  • Tell your prescriberContact your prescriber if it's frequent or causing distress.

Liver problems

Rare (post-marketing reports)

Signs: yellow skin or eyes, dark urine, or pain in the upper right of your tummy, with or without unexplained nausea.

  • Get help todayStop atomoxetine and contact your prescriber urgently if any of these occur. Do not wait.

Acute angle-closure glaucoma

Very rare

Sudden eye pain, blurred vision, or seeing halos around lights.

  • Call 999Go to the A&E eye unit immediately.

This is the full list for this guide, including uncommon and rare effects. For step-by-step tips on managing the common ones, and when to speak to your prescriber, see Atomoxetine (Strattera) side effects: what helps.

Section 6

When should I get help while taking atomoxetine?

Call 999 for severe or spreading chest pain, signs of a stroke, a first seizure, severe breathing difficulty, collapse or a severe allergic reaction (sudden swelling of the lips, mouth or throat). Go to A&E for an erection lasting more than 2 hours. Stop atomoxetine and contact your prescriber urgently for yellow skin or eyes. Contact your care team today for new thoughts of self-harm, or call 999 if you might act on them.

Emergency: call 999 or go to A&E immediately

  • Priapism: an erection lasting more than 2 hours. This is a medical emergency. It doesn't matter whether it is painful or not. Go to A&E immediately. Every hour of delay increases the risk of permanent injury.
  • Severe chest pain, or chest pain spreading to your arm, jaw or back
  • Sudden difficulty speaking, face drooping, arm weakness, vision changes or sudden severe headache, even if it passes quickly: call 999 immediately
  • Severe breathing difficulty or collapse
  • Loss of consciousness
  • A first seizure
  • Thoughts of harming yourself or someone else that you feel you might act on, or you have harmed yourself
  • Severe allergic reaction (anaphylaxis): sudden swelling of the lips, mouth, throat or tongue, or difficulty breathing or swallowing. Call 999.
No action

Expected: keep going

Common in the first few weeks: no action usually needed

  • Mild nausea in the first 1–2 weeks, especially before eating: take it with food
  • Reduced appetite during the day
  • Dry mouth: drink water regularly; sugar-free gum helps
  • A slight headache in the first few days
  • Feeling not much different in the first 1–3 weeks; this is completely normal; the medication takes weeks to build up
  • Feeling tired in the first week or two
Contact prescriber

Contact your prescriber within a few days

Not urgent: but worth discussing if ongoing

  • Nausea, reduced appetite, or stomach discomfort that hasn't settled after 3 weeks
  • Significant unintended weight loss
  • Sleep problems that don't improve after the first few weeks
  • Difficulty passing urine or a weak stream that doesn't improve
  • Erection difficulties or delayed ejaculation that are bothering you
  • Raised blood pressure if you check it at home
  • Feeling flat, low, or irritable: especially if this is a change from your usual self
  • Headache that isn't eased by paracetamol and water
  • Fingers or toes turning white or blue in the cold (Raynaud's)
Urgent

Contact your prescriber today: don't wait

Do not wait for a routine appointment

  • New or worsening thoughts of self-harm or suicide: contact your care team today; if you can't reach them, use the out-of-hours crisis line or call 111
  • Yellow skin or eyes, dark urine, or pain in the upper right of your tummy, with or without unexplained nausea: signs of liver problems; stop atomoxetine and contact your prescriber urgently
  • Sudden eye pain, blurred vision, or seeing halos around lights: possible acute angle-closure glaucoma; go to the A&E eye unit straight away
  • Mild chest pain, or a fast or irregular heartbeat when resting
  • A rash that spreads rapidly
  • Worsening of existing epilepsy
  • Signs of very high blood pressure (severe headache, vision changes, confusion)
  • Cannot pass urine at all: go to A&E or call 111 now

What you can safely try while waiting for a review

  • Take your dose with a meal or snack to reduce nausea
  • Drink plenty of water throughout the day
  • Sugar-free gum or mints help with dry mouth
  • Keep a brief weekly note of how things are going: gradual improvement can be easy to miss without tracking
  • Don't be discouraged in the first few weeks; the medication takes time to build up
  • Take at the same time every day for the most stable coverage
  • Paracetamol can usually be taken for headaches alongside atomoxetine: check with a pharmacist if you have other health conditions or take other medicines
Section 7

Frequently asked questions about atomoxetine

I've been taking it for a week and nothing is happening: is it working?

One week is often too early to judge atomoxetine's benefit. Improvement may develop gradually over several weeks. Your prescriber will review the dose, time on treatment, daily functioning and side effects before deciding whether it is helping. Keep brief weekly notes, and report troublesome effects promptly.

Do I have to have tried stimulants first before I can get atomoxetine?

Not necessarily. In UK practice, atomoxetine is often tried after stimulants: but there are many valid reasons to start with atomoxetine directly. These include: preference for a non-controlled drug, medications that interact with stimulants, specific health conditions, comorbid anxiety, or a history of substance use. Your prescriber will discuss which option makes most sense for your situation.

Can I take it with my antidepressant?

It depends which one. Some antidepressants: particularly fluoxetine (Prozac) and paroxetine (Seroxat): slow down the enzyme that processes atomoxetine. This can cause your atomoxetine level to become 5–7 times higher than expected at a standard dose. This doesn't mean you can't take them together; it means your prescriber needs to know and will start you on a lower dose of atomoxetine. Always give your full medication list before starting.

One antidepressant that must never be combined with atomoxetine: MAOIs (e.g., phenelzine, tranylcypromine, or high-dose selegiline). There must be at least 14 days between stopping an MAOI and starting atomoxetine. This combination can cause a dangerous spike in blood pressure.

Will it show up on a drug test?

No. Atomoxetine is not a stimulant and not a controlled drug. Standard workplace, occupational health, or forensic drug screening tests look for controlled substances: and atomoxetine is not one of them. It will not cause a positive result.

I have anxiety as well as ADHD: is it safe for me?

Yes, and there is specific clinical evidence that atomoxetine helps with both. In a large randomised trial, atomoxetine significantly improved anxiety symptoms alongside ADHD symptoms. Some stimulants can worsen anxiety in certain people: atomoxetine doesn't have this profile. Let your prescriber know about your anxiety so they can factor it in.

Does it affect sleep?

Atomoxetine can affect sleep. Some people feel sleepy, while others have difficulty falling or staying asleep. Tell your prescriber about the pattern. They may review your dose or dosing schedule. Do not change the schedule yourself, and do not drive if you are sleepy or otherwise impaired.

Can I drink alcohol while taking it?

Alcohol isn't an absolute no with atomoxetine, but there are two things worth knowing. Both alcohol and atomoxetine affect blood pressure: their effects can add together, so heavy drinking can increase cardiovascular strain. Atomoxetine is also processed by the liver, and alcohol adds to the burden on your liver: atomoxetine carries a rare but real risk of liver problems, so heavy alcohol use on top of this isn't a good combination. Moderation is strongly advisable.

If you have ADHD and also find alcohol use difficult, tell your prescriber: there's actually some positive evidence that atomoxetine can help reduce heavy drinking days for people with both conditions.

What happens if I miss a dose?

Take it as soon as you remember, unless it's nearly time for your next scheduled dose: in which case skip it and continue as normal. Don't double up. An occasional missed dose won't cause a rebound effect, but consistent daily dosing gives you the most stable coverage.

Do I have to take it on weekends and holidays?

Yes. Atomoxetine works by maintaining a steady level in your system: it's not something you take only on days when you need to focus. Taking 'medication holidays' as some people do with stimulants isn't appropriate with atomoxetine. Daily dosing is what keeps the therapeutic effect stable.

I'm thinking about getting pregnant: what should I know?

Pregnancy: Tell your prescriber before stopping or continuing atomoxetine. The current evidence (BUMPS) doesn't show that atomoxetine causes birth defects, but the data is limited. If taken close to delivery, a baby may have some withdrawal symptoms (jitteriness, difficulty feeding).

Breastfeeding: There is no published human data on atomoxetine in breast milk (Breastfeeding Network). There is a risk of drowsiness in your baby and, in some babies, a risk of the medication building up in their system (particularly if your baby processes CYP2D6 slowly). This needs an individual review with your specialist: speak to your prescriber before deciding either way. Do not stop atomoxetine without talking to your prescriber or midwife first.

Section 8

What should I ask my prescriber about atomoxetine?

Questions worth raising at your next review. You don't need to cover all of them: pick the ones that feel most relevant.

  • Is atomoxetine the right choice for me first, or would a stimulant be better for my situation?
  • Do any of my current medications interact with atomoxetine: especially fluoxetine, paroxetine, or bupropion?
  • Should I take it once a day or split into two doses?
  • What should I do if I get nausea at the start: is there anything that helps?
  • What are the signs of liver problems I should watch for?
  • What should I do if I think I'm having an erection emergency?
  • It's been [X] weeks and I'm not noticing much: is this still within the expected window, or should we consider adjusting the dose?
  • Have I had enough time at the right dose, or is there more room to go up?
  • Can my GP now manage my prescription on a shared care basis, or does it need to stay with my specialist?
  • How long am I likely to need to take this?
  • If I decide to stop, is there anything I need to do: or can I just stop?
Section 9

Atomoxetine: notes for GPs and clinicians

For GPs and clinicians

Clinical notes by , ADHD Advanced Practitioner and Clinical Prescribing Pharmacist.

ClinicalLicensing and indication

Atomoxetine is the only non-stimulant ADHD medication with a specific UK adult ADHD licence. Indicated for ADHD in adults, particularly when stimulants have failed, are contraindicated, or are not preferred. Also has RCT evidence for comorbid anxiety and alcohol use disorder (AUD).

ClinicalDosing

Adults ≥70kg: Start 40mg once daily for ≥7 days. Standard maintenance: 80mg/day. Maximum: 100mg/day. Adults <70kg: Start 0.5mg/kg/day. Target: 1.2mg/kg/day. Maximum: 1.4mg/kg/day or 100mg. Dose increases no sooner than every 7–14 days. Split dosing (e.g. 40mg morning + 40mg evening) can reduce peak-related GI side effects without compromising efficacy. Hepatic impairment: Child-Pugh B → 50% dose reduction. Child-Pugh C → 75% dose reduction. (Documented, dose-adjustment guidance available: unlike MPH/dexamfetamine.) Renal impairment: No dose adjustment required: not primarily renally excreted.

ClinicalCYP2D6 interactions (clinically critical)

Atomoxetine is primarily metabolised by CYP2D6. CYP2D6 poor metabolisers (PMs, ~7% of population) achieve plasma levels 5–10× higher than extensive metabolisers (EMs) and have a t½ of ~22 hours vs ~5 hours. Fluoxetine and paroxetine are potent CYP2D6 inhibitors: co-administration converts EMs to phenotypic PMs. AUC increases 5–7 fold. In this context, start atomoxetine at 40mg and do not exceed 80mg without clinical justification and monitoring. Bupropion is also a CYP2D6 inhibitor: same caution applies. The clinical implication: standard dosing guidance may overdose patients who are PMs or who take CYP2D6 inhibitors. This is a common source of unnecessary adverse events.

ClinicalMAOI contraindication

Absolute contraindication. MAOIs + atomoxetine → severe hypertensive crisis. 14-day washout from MAOI before starting atomoxetine. No exceptions.

ClinicalCardiovascular monitoring

Same baseline and ongoing monitoring as for stimulants: HR and BP at baseline, each dose change, and at least 6-monthly at stable dose. Contraindications include severe hypertension, symptomatic cardiovascular disease, and severe arrhythmia. Noradrenergic mechanism produces similar cardiovascular signal to stimulants: do not assume non-stimulant = cardiovascular risk-free.

ClinicalLiver toxicity

Rare post-marketing reports of severe hepatotoxicity, including fulminant liver failure. Onset variable: weeks to months. Counsel all patients on warning signs: jaundice, dark urine, right upper quadrant pain, unexplained nausea. Confirmed jaundice or significant liver enzyme elevation = stop immediately. Do not rechallenge. Avoid concurrent heavy alcohol use (additive hepatic burden).

ClinicalPriapism

Rare but documented; noradrenergic mechanism in penile vasculature. All male patients must be counselled at initiation. Erection >2 hours = medical emergency; go to A&E. Do not observe and wait. Permanent ischaemic injury risk escalates with each hour of delay.

ClinicalPregnancy and breastfeeding

Pregnancy (BUMPS December 2022): No clear evidence of teratogenicity but data limited. Possible transient neonatal withdrawal symptoms if used near delivery (jitteriness, poor feeding). Do not stop abruptly: planned reduction with obstetric/psychiatric input. Manufacturer advises avoidance.

Breastfeeding: No published human data. Rat data shows low milk transfer, but CYP2D6 PM status in infant (relevant in ~7% neonates) could cause drug accumulation. No 'safe' conclusion can be drawn. Requires individual specialist review: do not give standard reassurance. Case-by-case decision with full discussion of risk/benefit.

ClinicalResponse timeline and shared care

Clinical trial response data: ~47% of responders show first improvement by week 4; ~76% by week 12; ~85% by week 26; ~96% by week 52. Benefit may develop gradually over several weeks. Judge response on the dose reached, time on treatment, daily functioning and side effects rather than a fixed waiting period, and act promptly on troublesome effects.

Atomoxetine is not a Schedule 2 CD. GPs can prescribe on a standard FP10 repeat prescription. Shared care arrangements for ongoing prescribing are straightforward once initiated by a specialist. No CD prescription restrictions apply.

Patient page: How shared care works, and what to do if your GP declines or stops it

This guide is written for educational purposes and does not constitute medical advice. Always follow the guidance of your prescriber or pharmacist. If you have concerns about your medication, contact your clinical team.

Sources

About this guide

Written and clinically reviewed by
ADHD Advanced Practitioner and Clinical Prescribing Pharmacist
First published
Last updated
Last reviewed
Next review
What changed
October 2026: clearer advice on when to call 999 (severe or spreading chest pain, severe breathlessness, or thoughts of self-harm you might act on) and when to get help the same day. Side effect frequencies now use the categories in the product information (SmPC). The headache advice now says drinking enough water may help. Paracetamol can usually be taken, but check with a pharmacist if you have other health conditions or take other medicines. The amber help tier now reads "within a few days" rather than "next review", so significant weight loss is no longer a next-review item. The liver warning now names yellow skin or eyes, dark urine and pain in the upper right of the tummy, with nausea only when unexplained and alongside those; being unable to pass urine at all is a same-day A&E or 111 item. 21 October 2026: the first-week and sleep answers, and the insomnia advice, no longer say it is probably working or that sleep is usually unaffected or less affected than with stimulants; atomoxetine can cause sleepiness or difficulty sleeping. The clinician note no longer requires a fixed 12-week trial before judging response.

“Last updated” is when the content last changed. “Last reviewed” is when it was last checked against current sources.

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