What blood pressure medication can a patient taking Strattera (atomoxetine) 40 mg and venlafaxine (Effexor) 75 mg with orthostatic hypotension take?

Blood Pressure Medication Selection for Patients on Strattera and Venlafaxine with Orthostatic Hypotension

For a patient taking atomoxetine (Strattera) 40 mg and venlafaxine 75 mg who experiences orthostatic hypotension, long-acting dihydropyridine calcium channel blockers (such as amlodipine) or ACE inhibitors/ARBs are the recommended first-line antihypertensive agents, as these have minimal impact on orthostatic symptoms compared to other blood pressure medications. 1, 2

Critical Context: The Medication Challenge

Your patient faces a complex situation where both current medications can worsen orthostatic hypotension:

• Atomoxetine (Strattera) is a norepinephrine reuptake inhibitor that paradoxically can cause orthostatic hypotension despite its sympathomimetic properties 3, 4
• Venlafaxine is an SNRI that commonly causes orthostatic hypotension, particularly at doses ≥75 mg 5
• Adding traditional antihypertensive agents could dangerously compound this problem 1

Preferred Antihypertensive Agents

First-Line: Dihydropyridine Calcium Channel Blockers

Amlodipine is the optimal choice because it provides effective blood pressure control with minimal orthostatic effects 1, 2:

• Start with amlodipine 2.5-5 mg once daily 1
• Can be titrated to 10 mg daily as needed for blood pressure control 1
• Long-acting formulation provides 24-hour coverage without peaks that could worsen orthostatic symptoms 1

Alternative First-Line: ACE Inhibitors or ARBs

If calcium channel blockers are contraindicated or not tolerated 1, 2:

• ACE inhibitors: Start lisinopril 5-10 mg daily or enalapril 5 mg twice daily 1
• ARBs: Start losartan 25-50 mg daily or valsartan 80 mg daily 1
• These RAS blockers have minimal impact on orthostatic blood pressure compared to other antihypertensive classes 2, 6

Medications to Absolutely Avoid

Do not use the following agents as they will significantly worsen orthostatic hypotension 1, 2:

• Alpha-1 blockers (doxazosin, prazosin, terazosin): These are "associated with orthostatic hypotension, especially in older adults" and should be avoided 1, 5
• Diuretics (thiazides, loop diuretics): These cause volume depletion and are "the most important culprits" in drug-induced orthostatic hypotension 2, 5
• Non-selective beta-blockers (propranolol, nadolol): These impair compensatory tachycardia needed during postural changes 1, 2
• Centrally-acting agents (clonidine, methyldopa): These have "significant CNS adverse effects" and worsen orthostatic symptoms 1

Essential Non-Pharmacological Measures

Implement these strategies concurrently with any antihypertensive therapy 1, 2:

• Increase fluid intake to 2-3 liters daily unless contraindicated 2
• Increase salt intake to 6-9 grams daily if no heart failure present 1, 2
• Physical counter-maneuvers: Teach leg crossing, squatting, and muscle tensing when symptoms occur 1, 2
• Compression garments: Use waist-high compression stockings (30-40 mmHg) to reduce venous pooling 2
• Elevate head of bed by 10 degrees during sleep to prevent nocturnal polyuria 2
• Smaller, frequent meals to reduce postprandial hypotension 1, 2

Monitoring Protocol

Measure orthostatic vital signs at every visit using this standardized approach 1, 2:

1. Measure blood pressure after 5 minutes of lying/sitting
2. Have patient stand and measure blood pressure at 1 minute and 3 minutes
3. Document both systolic and diastolic changes
4. Orthostatic hypotension is defined as a drop of ≥20 mmHg systolic or ≥10 mmHg diastolic 1

Reassess within 1-2 weeks after initiating or changing antihypertensive therapy 2

If Orthostatic Symptoms Persist Despite Optimal Antihypertensive Selection

Consider whether blood pressure treatment is truly necessary at this time, as the therapeutic goal should prioritize minimizing postural symptoms over achieving specific blood pressure targets 1, 2.

If hypertension treatment is essential and orthostatic symptoms remain problematic despite amlodipine or ACE inhibitor/ARB therapy 7, 2:

Add Fludrocortisone as First-Line Orthostatic Agent

• Start fludrocortisone 0.05-0.1 mg once daily 7, 2
• Titrate to 0.1-0.3 mg daily based on response 1, 2
• Monitor for supine hypertension, hypokalemia, heart failure, and peripheral edema 2
• Contraindicated in patients with active heart failure or severe renal disease 2

Alternative: Midodrine

• Start midodrine 2.5-5 mg three times daily 2
• Critical timing: Last dose must be at least 4 hours before bedtime (no later than 6 PM) to prevent supine hypertension 2
• Can increase standing systolic BP by 15-30 mmHg for 2-3 hours 2
• Monitor for supine hypertension during sleep 2

Consider Droxidopa

• FDA-approved specifically for neurogenic orthostatic hypotension 1, 2
• Particularly effective if autonomic dysfunction is present 2
• May reduce fall risk 2

Critical Pitfalls to Avoid

Do not simply reduce the dose of medications causing orthostatic hypotension—switch to alternative therapy instead 2:

• Reducing venlafaxine dose may compromise psychiatric symptom control
• Reducing atomoxetine dose may compromise ADHD management
• The solution is choosing the right antihypertensive class, not dose reduction of existing medications 1, 2

Do not combine multiple vasodilating agents (ACE inhibitor + calcium channel blocker + diuretic) without extremely careful monitoring, as this dramatically increases orthostatic hypotension risk 2

Do not overlook volume depletion as a contributing factor—ensure adequate hydration before escalating pharmacotherapy 2

Do not use combination RAS blockade (ACE inhibitor + ARB together), as this is explicitly not recommended and provides no additional benefit 1

Treatment Algorithm Summary

1. Confirm orthostatic hypotension with standardized measurements (5 min supine, then 1 and 3 min standing) 1, 2
2. Implement non-pharmacological measures (fluids, salt, compression, counter-maneuvers) 2
3. If antihypertensive needed: Start amlodipine 2.5-5 mg daily OR ACE inhibitor/ARB at low dose 1, 2
4. Avoid alpha-blockers, diuretics, non-selective beta-blockers, and centrally-acting agents 1, 2
5. If orthostatic symptoms persist: Add fludrocortisone 0.05-0.1 mg daily or midodrine 2.5-5 mg TID (last dose before 6 PM) 7, 2
6. Monitor closely: Reassess within 1-2 weeks, check orthostatic vitals at every visit 2