A guide for primary care clinicians managing ADHD medication side effects

Introduction

Over the past two decades, adult attention deficit hyperactivity disorder (ADHD) diagnoses in the UK have soared, reflecting both heightened awareness and recognition of ADHD as a lifelong condition.¹ Appropriate treatment, often involving stimulant medication, can be transformative for patients, improving concentration, regulating emotions, and making daily life more manageable. Evidence suggests that effective ADHD management can lower all-cause mortality and reduce the incidence of accidental injuries, traumatic brain injury, substance misuse, and cigarette smoking. It may also help mitigate risks such as educational underachievement, depression, suicide, and criminal activity.² These elevated risks underscore the importance of treating ADHD.

For GPs, the increasing diagnosis and treatment of ADHD have brought both opportunities and challenges. Shared care agreements often position GPs as central figures in ADHD management, with responsibilities for prescribing and monitoring stimulant medications.³ While this collaborative model can improve patient outcomes and reduce costs, it also places significant demands on GPs, who must balance patient safety, treatment optimisation, and complex needs — all within the constraints of a busy practice. In addition, private prescriptions for ADHD medications may fall out with any shared care arrangements, yet patients will attend with symptoms that may, or may not, be attributable to these medications.

The context of ADHD management in primary care

ADHD is estimated to affect 3%–4% of adults, often presenting with symptoms such as inattention, impulsivity, and hyperactivity.⁴ Treatment typically follows the National Institute for Health and Care Excellence guidelines, which recommend:⁵

• first-line treatments: stimulants, such as methylphenidate or amphetamines, which enhance focus by modulating dopamine and norepinephrine; and

• second-line treatments: non-stimulants, including atomoxetine, which are particularly useful for patients who cannot tolerate stimulants or for whom stimulants prove ineffective.

Brief medication guide: dosages and common side effects

Troubleshooting problems in people prescribed ADHD medications

Patients prescribed ADHD medications may present to general practice with various symptoms, regardless of whether formal pathways exist. These symptoms might or might not be directly related to their medication.

Table 1.

Common ADHD medications, typical dosages, and key practical advice^a

Medication	Formulations	Common side effects	Key practical advice
Methylphenidate	Immediate release: 5 mg, 10 mg, 20 mg (for example, Ritalin®)	Reduced appetite, insomnia, headache, increased heart rate	2–3 doses daily. Regularly assess focus, mood, and cardiovascular health
Methylphenidate	Modified release: 18 mg, 27 mg, 36 mg, 54 mg (for example, Concerta XL®)	Reduced appetite, insomnia, headache, increased heart rate	Take once daily in the morning. Regularly assess focus, mood, and cardiovascular health
Lisdexamfetamine Modified release	Capsules: 20 mg to 70 mg (for example, Elvanse®)	Decreased appetite, dry mouth, insomnia, weight loss	Take once daily in the morning. Assess impact on productivity, emotional regulation, and cardiovascular health
Dexamfetamine Immediate release	Tablets: 5 mg to 20 mg (for example, Amfexa®); solution: 1 mg/mL	Appetite loss, mood swings, dizziness, insomnia	2–4 doses daily, spaced 4–6 hours apart. Monitor energy levels, mood stability, and heart rate
Atomoxetine	Capsules: 10 mg to 100 mg (for example, Strattera®)	Fatigue, dry mouth, nausea, mood swings	Take once or twice daily. Watch for changes in emotional control, focus, and liver health

^aAdapted from Avon and Wiltshire Mental Health Partnership NHS Trust.⁶ ADHD = attention deficit hyperactivity disorder.

There are three common areas to consider:

• Side effects screening:

  • ○ GPs should be aware of common side effects, such as appetite changes, sleep disturbances, palpitations, or mood fluctuations. See Box 1 for troubleshooting challenges and potential solutions for consideration.

  • ○ If side effects persist or significantly impact quality of life, and are not attributable to other medications or conditions, the GP should consider referring the patient to secondary care or the treatment-initiating specialist clinic for reassessment.

• Physical health monitoring:

  • ○ Patients should be having physical health checks, ideally every 6 months, including blood pressure, heart rate, weight, and body mass index.

  • ○ Ideally, these will include screening for new or emerging cardiac concerns.

• Comorbidity review:

  • ○ Co-occurring mental health conditions, such as anxiety or depression, are common.

  • ○ It is reasonable to assess substance use, including alcohol or recreational drugs, and remain vigilant for signs of medication misuse or diversion.

Box 1. Troubleshooting challenges with ADHD medications.

Challenge	Potential solutions
Sleep disturbances	Discuss strategies for improving sleep hygiene, such as maintaining a consistent bedtime and avoiding stimulants late in the day Adjust medication timing to earlier in the daya If issues persist, refer to secondary care to explore non-stimulant options
Weight loss/appetite suppression	Encourage regular, balanced meals and consistent meal times Suggest taking medication with or immediately after food Consider implementing medication-free days, if clinically appropriatea Monitor weight trends; if persistent issues arise, refer to secondary care for dose adjustments or alternative treatments
Medication losing efficacy	Confirm adherence to the prescribed regimen and evaluate lifestyle factors such as stress, diet, and sleep Screen for co-occurring conditions such as anxiety or depression Consider a temporary medication holidaya If no improvement, refer to secondary care to explore alternative medication options

^aMay need specialist advice/referral. ADHD = attention deficit hyperactivity disorder.

When do patients need to be referred back to secondary care?

GPs should consider referring patients to secondary care or the treatment-initiating clinic in the following situations:

• significant weight loss — unexplained reductions of more than 5% of body weight;

• new cardiac symptoms — if cardiac symptoms resolve after discontinuing the medication, referral to secondary care is recommended to explore alternative treatment options;

• severe psychiatric symptoms — including suicidal ideation or anxiety that cannot be managed in primary care;

• difficulty managing symptoms — despite optimal dosing, symptom control remains inadequate;

• unmanageable side effects — persisting issues that cannot be resolved in primary care; and

• medication concerns — any suspicion of misuse or diversion.

Conclusion

The sudden rise in individuals referred for ADHD assessments and subsequently discharged to general practice has added significant responsibilities to an already overstretched system. While GPs are experienced in managing psychiatric medications under existing pathways, ADHD care presents unique challenges that require tailored resources and support. Encouragingly, ADHD medications have a safer profile and provide immediate, meaningful benefits for many patients, helping them thrive in their daily lives.