What should be done for an adult patient with ADHD, hypertension, and depression experiencing dizziness and lightheadedness after taking atomoxetine, hydrochlorothiazide, and Wellbutrin (bupropion)?

Immediate Management of Dizziness and Lightheadedness with Atomoxetine, Hydrochlorothiazide, and Bupropion

Stop the atomoxetine immediately and check orthostatic vital signs (blood pressure and heart rate supine and standing) to assess for orthostatic hypotension, which is the most likely cause of these symptoms given the combination of a diuretic with a norepinephrine reuptake inhibitor. 1

Assess the Cardiovascular Cause

The combination of hydrochlorothiazide (which depletes volume) and atomoxetine (which can cause orthostatic hypotension) creates a high-risk scenario for symptomatic hypotension:

• Measure orthostatic vital signs immediately: Check blood pressure and heart rate lying down, then after standing for 1-3 minutes. A drop of ≥20 mmHg systolic or ≥10 mmHg diastolic, or symptoms upon standing, confirms orthostatic hypotension. 1

• Atomoxetine specifically causes orthostatic hypotension and syncope: The FDA label reports 0.2% of patients experience orthostatic hypotension and 0.8% experience syncope, with atomoxetine requiring caution in conditions predisposing to hypotension or abrupt blood pressure changes. 1

• Volume depletion from hydrochlorothiazide exacerbates this risk: The diuretic effect reduces intravascular volume, making orthostatic symptoms more likely when combined with atomoxetine's cardiovascular effects. 1

Immediate Actions

• Hold the atomoxetine: Do not continue this medication until cardiovascular stability is confirmed and the medication regimen is adjusted. 1

• Consider reducing or holding the hydrochlorothiazide: If orthostatic hypotension is confirmed, the diuretic dose may need reduction or temporary discontinuation to restore adequate volume status. 2

• Maintain the bupropion: While bupropion can cause modest blood pressure increases (+5.9 mmHg systolic), it is less likely to cause hypotension and dizziness compared to the atomoxetine-hydrochlorothiazide interaction. 2, 3

Risk Assessment for Atomoxetine Continuation

This is only the second dose of atomoxetine at 18mg (a low starting dose), yet symptoms have already emerged, suggesting this patient may be particularly sensitive to its cardiovascular effects:

• Atomoxetine causes dose-dependent cardiovascular effects: In clinical trials, dizziness was a commonly reported adverse effect in adults, along with modest increases in heart rate (mean 7.5 beats/minute in extensive metabolizers, 11 beats/minute in poor metabolizers). 4, 5, 6, 3

• Poor metabolizers have greater cardiovascular effects: If this patient is a CYP2D6 poor metabolizer, they will have higher atomoxetine levels and more pronounced blood pressure and heart rate changes. 1

• The combination with a diuretic is particularly problematic: Atomoxetine should be used with caution in conditions predisposing to hypotension, and volume depletion from hydrochlorothiazide creates exactly this scenario. 1

Alternative ADHD Management Strategy

If ADHD treatment is still needed after stabilization, consider switching to a stimulant medication (methylphenidate or amphetamine) rather than restarting atomoxetine, as stimulants are less likely to cause orthostatic hypotension:

• Stimulants cause modest pressor effects rather than hypotension: Methylphenidate and amphetamines typically increase blood pressure (+4-5 mmHg systolic) and heart rate, making orthostatic hypotension less likely. 3

• Monitor blood pressure with any ADHD medication: All catecholaminergic ADHD medications require baseline and periodic blood pressure and heart rate monitoring. 3

Critical Monitoring Parameters

Before any medication adjustment:

• Check for volume depletion signs: Assess mucous membranes, skin turgor, and recent fluid intake/output. 2

• Review timing of medications: If medications are taken simultaneously, separating administration times may reduce additive hypotensive effects. 2

• Assess for other contributing factors: Recent illness, inadequate fluid intake, or hot weather can worsen orthostatic symptoms with this medication combination. 1

Common Pitfall to Avoid

Do not simply reduce the atomoxetine dose and continue it with the current diuretic regimen—the orthostatic hypotension risk remains even at lower atomoxetine doses when combined with volume depletion from hydrochlorothiazide. The FDA label explicitly warns about using atomoxetine in conditions predisposing to hypotension. 1