ADHD Medicines to help symptoms of adult attention deficit hyperactivity disorder (ADHD)
This guide can help you to make a more informed choice about which medication may be best for you if you have been diagnosed with adult ADHD and offered treatment with medicines. A member of the adult ADHD service will be happy to discuss anything included in this guide with you.
Why have I been prescribed medicines for adult ADHD?
People with ADHD often experience a number of symptoms including difficulty sustaining attention, hyperactivity and restlessness/impulsivity. You may have been prescribed medications to help with these symptoms.
What medicines are available?
Medications may help with these symptoms and effects of ADHD and help you get your life back on track.
There are currently two classes of medications that you may be prescribed:
| Stimulant medication (amphetamine based) |
Non-stimulant |
|
Methylphenidate (eg. Concerta®, Medikinet®, Equasym® and Ritalin®) Lisdexamfetamine (eg. Elvanse®/Elvanse Adult) |
Atomoxetine (eg. Strattera®) Guanfacine (eg. Intuniv®) |
NICE Guidance: Key Points
According to NICE [3]:
First-line medication in adults: methylphenidate or lisdexamfetamine.
Alternatives: atomoxetine or guanfacine if stimulants are unsuitable or not tolerated.
Specialist initiation: medicines should be started under supervision of an ADHD specialist.
Annual review: treatment reviewed at least every 12 months.
Holistic care: support should include psychological, educational, and social interventions.
How Do ADHD Medicines Work?
Neurotransmitters and pathways
Dopamine: linked to motivation, reward, and sustaining effort on tasks. Deficiency contributes to distractibility and low task persistence.
Noradrenaline (norepinephrine): linked to alertness, arousal, and impulse control. Reduced activity contributes to poor concentration and impulsivity.
Stimulant and non-stimulant medications work differently on these neurotransmitters:
Stimulants: block reuptake or promote release of dopamine/noradrenaline in the synapse, enhancing signalling [4].
Atomoxetine: a selective norepinephrine reuptake inhibitor (NRI), prolonging noradrenaline availability [5].
Guanfacine: an alpha-2A adrenergic receptor agonist, strengthening prefrontal cortex regulation of attention and impulses [6].
Medication Classes and Mechanisms
Methylphenidate (Concerta XL®, Medikinet XL®, Ritalin®)
Class: CNS stimulant (piperidine derivative).
Mechanism: Blocks the reuptake transporters for dopamine and noradrenaline, increasing their levels in the synaptic cleft [4].
Effect: Improves sustained attention and reduces hyperactivity/impulsivity.
Onset: 1–2 hours.
Duration: 3–12 hours depending on formulation.
Lisdexamfetamine (Elvanse®, Elvanse Adult®)
Class: CNS stimulant, prodrug of dexamfetamine.
Mechanism: After ingestion, it is converted into dexamfetamine. This increases release of dopamine and noradrenaline from presynaptic neurons and blocks their reuptake [4].
Effect: Strong improvement in focus and impulse control.
Onset: 1–2 hours.
Duration: All day.
Atomoxetine (Strattera®)
Class: Selective norepinephrine reuptake inhibitor (NRI).
Mechanism: Inhibits the noradrenaline transporter, increasing extracellular noradrenaline (and secondarily dopamine in the prefrontal cortex) [5].
Effect: Reduces hyperactivity and impulsivity, and improves emotional regulation.
Onset: Takes 2–4 weeks for full benefit.
Duration: All day.
Guanfacine (Intuniv®)
Class: Selective alpha-2A adrenergic receptor agonist.
Mechanism: Stimulates postsynaptic alpha-2A receptors in the prefrontal cortex, strengthening “top-down” regulation of attention and impulses [6].
Effect: Improves hyperactivity, emotional control, and sleep in some individuals.
Onset: Up to 1 week.
Duration: All day.
Are these medications safe to take?
These medications are normally safe to take but you should let your prescriber know if any of the following apply to you:
- Epilepsy, heart, liver or kidney trouble or glaucoma
- If you take any other medications prescribed by another doctor, bought over the 6 counter and alternative remedies e.g. herbal medicines
- If you are pregnant or breast-feeding or wish to become pregnant
Which medication will be offered to me?
A healthcare professional will discuss medication options with you. However, these will depend on a number of circumstances including:
- Whether you have other conditions e.g. Tourette’s syndrome, tics or epilepsy
- Side effects from medication
- Dosing frequency of medication.
- If you are prescribed any other medications
- Your preference
- Which medication works best for you
How long should I take the medication for?
Your medication will be reviewed by a specialist every year although you will need to decide what works for you. The medicines do not ‘cure’ ADHD, they just help with the symptoms.
What times of the day will the medications work?
There are different formulations of methylphenidate and this determines how long they stay in the body. For example, Ritalin or Dexamphetamine are immediate release tablets and their effect wears off in a few hours after taking them. This means your doctor will ask you to take it two or three times a day, giving you the ability to control when the maximum effect of the medication takes place.
There are also slow-release tablets which include Equasym XL, Medikinet XL or Concerta XL. The effects of these tablets will last longer so your doctor will usually ask you to take the tablets once a day. Atomoxetine can be taken once or twice a day and for most people is effective for the duration of the day.
The table below offers more explanation.
| Medication | Dosage | How quickly does the medication work? |
| Methylphenidate tablets (immediate release) | Usually prescribed two to three times daily | Usually takes one to two hours to start working |
| Concerta XL (methylphenidate slow release) | Usually prescribed once daily. Effects last for 12 hours | Usually takes one to two hours to start working |
| Equasym XL (methlyphenidate slow release) | Usually prescribed once daily. Effects last for eight hours | Usually takes one to two hours to start working |
| Medikinet XL (methylphenidate slow release) | Usually prescribed once daily. Effects last for eight hours | Usually takes one to two hours to start working |
| Dexamphetamine tablets (immediate release) | Usually prescribed three to four times daily. Effects last for three to four hours | Usually takes one to two hours to start working |
| Atomoxetine | Usually prescribed once or twice daily. Effects usually last all day | Usually takes two to four weeks to start working |
| Lisdexamfetamine | Usually prescribed once daily in the morning. Effects usually last all day | Usually takes one to two hours to start working |
| Guanfacine (slow release) | Usually prescribed once daily in the morning | Usually takes up to a week to start working |
Possible side effects of ADHD medication
There are some possible side effects that can occur when taking ADHD medication, however these generally wear off after the first few weeks.
Your doctor will regularly monitor your weight, heart rate and blood pressure as well as any side effects you may experience. If you do suffer from any side effects your doctor may reduce, stop or change your medication.
You will need to keep a record of changes in symptoms and/or behaviour when you start medication or when the dose is changed.
Possible side effects include:
| Side effect | Common with methylphenidate and dexamphetamine | Common with atomoxetine | Common with guanfacine |
| Not being able to get to sleep | 3 | 3 | 3 |
| Not feeling hungry | 3 | 3 | 3 |
| Feeling sick or being sick or stomach pain | 3 | 3 | 3 |
| Headache | 3 | 3 | 3 |
| Feeling more anxious or nervous | 3 | ||
| Cough, sore nose and throat | 3 | ||
| Feeling angry irritable or low | 3 | 3 | |
| Feeling dizzy | 3 | 3 | 3 |
| Joint pain/muscle twitching | 3 | ||
| Constipation | 3 | 3 | |
| Rash | 3 | 3 | |
| Feeling tired | 3 | 3 | 3 |
| Weight gain | 3 | ||
| Increases blood pressure and pulse | 3 | 3 | |
| Decreases blood pressure and pulse | 3 |
Lifestyle and Daily Living Advice
ADHD medication works best when supported by healthy daily routines and lifestyle adjustments. These changes can improve effectiveness, reduce side effects, and promote long-term health.
Diet and Nutrition
- Regular meals: Stimulant medicines can reduce appetite, especially at lunchtime. Skipping meals can worsen irritability, fatigue, and poor concentration [2]. Try to eat small, balanced meals or snacks at regular times.
- Protein intake: Including lean protein (chicken, fish, eggs, legumes) in meals helps stabilise energy and may reduce medication “crash” effects later in the day.
- Complex carbohydrates: Wholegrains, fruit, and vegetables provide steady energy release, supporting focus throughout the day.
- Iron, zinc, and omega-3 fatty acids: Some research suggests that deficiencies in these nutrients may worsen ADHD symptoms. Foods such as oily fish, nuts, seeds, beans, spinach, and fortified cereals may help [1].
- Hydration: Dehydration can increase headaches and tiredness, which are also possible side effects of ADHD medicines. Aim for at least 6–8 glasses of water daily.
- Limit high-sugar foods: While sugar does not cause ADHD, sudden spikes and drops in blood glucose can worsen restlessness and mood swings.
- Meal timing with medication: Take medication after food where possible to reduce
Caffeine
Caffeine (in tea, coffee, cola, energy drinks, and pre-workout supplements) is itself a stimulant.
When combined with ADHD medication, it may cause:
- Jitteriness
- Increased heart rate or blood pressure
- Anxiety or agitation
- Sleep problems if taken in the afternoon or evening [3].
Advice: Limit or avoid caffeine, especially later in the day. If you are used to drinking large amounts, reduce gradually to avoid withdrawal headaches.
Alcohol
Alcohol is a depressant that interferes with concentration, mood, and sleep.
Combining alcohol with ADHD medication can:
- Increase risk of cardiovascular strain [3].
- Reduce the effectiveness of medication.
- Impair judgement and self-control, increasing impulsivity.
Advice: Limit or avoid caffeine, especially later in the day. If you are used to drinking large amounts, reduce gradually to avoid withdrawal headaches.
Recreational Substances
- Cannabis: May worsen attention, motivation, and short-term memory. It can also increase anxiety and interact unpredictably with prescribed stimulants.
- Cocaine and amphetamines: Dangerous to combine with ADHD medicines, as they may cause dangerously high blood pressure, irregular heart rhythms, or mental health crises.
- MDMA (ecstasy): Can deplete brain serotonin and dopamine, worsening ADHD symptoms long-term.
- Advice: Recreational drug use should be avoided if you are taking ADHD medication. Be honest with your prescriber about any substance use, as it can affect both safety and effectiveness of treatment.
Sleep and Rest
- ADHD itself is linked to delayed sleep onset and poor sleep quality. Medication can sometimes add to this by causing insomnia, especially if taken too late in the day.
- Tips for good sleep hygiene [1]:
- Keep a regular bedtime and wake time, even at weekends.
- Avoid screens, gaming, and social media for at least an hour before bed.
- Create a calming bedtime routine (reading, warm shower, meditation).
- Use blackout blinds or an eye mask to reduce light stimulation.
- Avoid large meals or caffeine late in the evening.
- Physical exercise earlier in the day can improve sleep quality, but avoid vigorous activity just before bed.
Exercise and Physical Activity
- Regular exercise improves mood, sleep, and executive functioning.
- Aerobic activities (e.g. running, cycling, swimming) increase dopamine and noradrenaline naturally, complementing medication effects [1].
- Mind-body activities such as yoga or martial arts may improve emotional regulation and focus.
- Advice: Aim for at least 150 minutes of moderate exercise per week (NHS guideline).
Emotional Health and Stress Management
- Stress can worsen ADHD symptoms and reduce medication effectiveness.
- Helpful strategies include:
- Mindfulness and relaxation exercises.
- Structured daily routines and use of reminders.
- Breaking large tasks into smaller, achievable steps.
- Talking therapies such as CBT, often recommended alongside medication by NICE [3].
Work, Study, and Daily Routines
- Many adults with ADHD benefit from:
- Planning tools (calendars, apps, alarms, checklists).
- Prioritising important tasks in the morning, when medication is usually most effective.
- Using noise-cancelling headphones or quiet spaces to reduce distractions.
- Regular breaks to maintain focus and avoid burnout.
Relationships and Social Life
- ADHD symptoms can impact relationships through forgetfulness, distractibility, or impulsivity.
- Open communication with family and friends can help them understand how ADHD and its treatment affect you.
- Peer support groups (in person or online) can provide shared strategies and emotional support [2].
Stopping your medication
If you are thinking of stopping your medication it is advisable to discuss this with your doctor or a healthcare professional beforehand.
References
[1] Volkow ND, Swanson JM. Clinical practice: Adult attention deficit–hyperactivity disorder. N Engl J Med. 2013.
[2] NHS. ADHD in adults. Available at: www.nhs.uk.
[3] NICE. Attention deficit hyperactivity disorder: diagnosis and management (NG87). 2018.
[4] Bolea-Alamanac B, et al. Evidence-based guidelines for the pharmacological management of ADHD: update from the British Association for Psychopharmacology. J Psychopharmacol. 2014.
[5] Upadhyaya HP, et al. Mechanism of action of atomoxetine in ADHD. CNS Drugs. 2013.
[6] Arnsten AFT. Guanfacine’s mechanism of action in the treatment of prefrontal cortical dysfunction. J Child Adolesc Psychopharmacol. 2010.