I take escitalopram (Lexapro) at 10 pm; can I take atomoxetine at 7:30 pm, and are there any known drug interactions between atomoxetine and ibuprofen or cyclobenzaprine (10 mg) used for back muscle spasms?

Timing and Drug Interaction Guidance for Atomoxetine with Lexapro

Your proposed timing of taking atomoxetine at 7:30 PM (2.5 hours before your 10 PM Lexapro) is reasonable and safe, allowing you to monitor for side effects before bed while maintaining separation between doses. 1

Timing Strategy

Your plan demonstrates good clinical judgment:

• Atomoxetine can be taken once or twice daily at consistent times, and evening dosing is explicitly acceptable per FDA labeling 1
• Taking it 2.5 hours before Lexapro gives you a window to assess tolerability (drowsiness, nausea, or activation) before sleep
• This spacing is adequate since there are no specific timing restrictions between these medications
• If drowsiness occurs, you'll be home and can adjust; if activation occurs, you still have time before bed to settle

The FDA label confirms atomoxetine can be taken with or without food and emphasizes consistency in timing rather than specific clock times 1.

Drug Interactions: Atomoxetine with Ibuprofen

Ibuprofen 400 mg can be safely taken with atomoxetine—there are no clinically significant interactions between these medications. 1

• The atomoxetine FDA label does not list NSAIDs as interacting medications 1
• While ibuprofen has cardiovascular considerations in high-risk patients, your occasional use for back pain (rather than chronic daily use) poses minimal concern 2
• Take ibuprofen as needed for your back spasms without concern for atomoxetine interaction

Drug Interactions: Atomoxetine with Cyclobenzaprine

Exercise significant caution with cyclobenzaprine (Flexeril) while on both atomoxetine and Lexapro—this combination carries risk of serotonin syndrome. 3

Critical Safety Concerns:

• Cyclobenzaprine combined with escitalopram (Lexapro) has documented case reports of serotonin syndrome 3
• While atomoxetine is primarily a norepinephrine reuptake inhibitor, the triple combination (atomoxetine + escitalopram + cyclobenzaprine) increases complexity
• The cyclobenzaprine FDA label notes increased drowsiness when combined with other medications 4

Practical Recommendations:

• Since you haven't needed cyclobenzaprine for over a week and ibuprofen is managing your symptoms, continue avoiding the muscle relaxer
• If back spasms worsen and ibuprofen becomes insufficient, contact your prescriber before restarting cyclobenzaprine
• Do not take cyclobenzaprine without medical supervision while on both Lexapro and atomoxetine

Serotonin Syndrome Warning Signs (seek immediate care if these occur):

• Agitation, confusion, rapid heart rate
• High fever, excessive sweating
• Muscle rigidity, tremors, or twitching
• Severe nausea/vomiting, diarrhea

Atomoxetine and Lexapro Combination

The combination of atomoxetine with escitalopram is used clinically, though research shows complex interactions:

• Animal studies demonstrate that atomoxetine can modulate escitalopram's effects through noradrenergic mechanisms 5
• Both medications require cardiovascular monitoring (blood pressure and heart rate) per atomoxetine's FDA label 1
• Escitalopram has dose-dependent QT prolongation effects, though generally well-tolerated 6

Driving and Work Safety

Your concern about operating vehicles at the car wash is appropriate:

• Atomoxetine may cause dizziness or affect alertness initially 1
• The FDA label specifically warns to "be careful until you know how atomoxetine affects you" regarding driving and operating machinery 1
• Consider starting atomoxetine on a day when you can assess tolerability before your physically demanding weekend work
• Evening dosing may minimize daytime impairment for your Monday-Friday office work

Monitoring Plan

Your doctor should check regularly while on atomoxetine 1:

• Blood pressure and heart rate (atomoxetine can increase both)
• Height and weight if applicable
• Liver function if symptoms develop
• Mental health symptoms (mood changes, anxiety)

Bottom line: Your 7:30 PM atomoxetine timing is appropriate. Ibuprofen is safe to use. Avoid cyclobenzaprine unless discussed with your prescriber given the serotonin syndrome risk with your current medications.