Contraindications for Adding Duloxetine
The absolute contraindications for adding duloxetine are concurrent use with MAOIs (including within 5 days of stopping duloxetine or within 14 days of stopping an MAOI), and concurrent use with linezolid or intravenous methylene blue due to the risk of serotonin syndrome. 1
Absolute Contraindications
- MAOI use: Do not use duloxetine with any MAOI intended to treat psychiatric disorders, as this combination creates an unacceptable risk of serotonin syndrome 1
- Timing restrictions: Wait at least 5 days after stopping duloxetine before starting an MAOI, and wait at least 14 days after stopping an MAOI before starting duloxetine 1
- Linezolid or IV methylene blue: Do not initiate duloxetine in patients currently receiving these medications due to their MAOI-like properties 1
Relative Contraindications and Cautions
- Uncontrolled narrow-angle glaucoma: Duloxetine may precipitate angle-closure attacks in susceptible patients 1
- Severe hepatic impairment: Duloxetine undergoes extensive hepatic metabolism and should be avoided in patients with cirrhosis or significant liver disease 1
- Severe renal impairment (CrCl <30 mL/min): Duloxetine is not recommended in patients with end-stage renal disease or severe renal dysfunction 1
- Concurrent use of other serotonergic drugs: Exercise caution when combining duloxetine with SSRIs, SNRIs, triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, or St. John's Wort due to additive serotonin syndrome risk 1
Clinical Considerations for Chronic Low Back Pain
- Evidence supports use: Duloxetine 60 mg daily demonstrates small but significant improvements in pain intensity (0.60-0.79 points on a 0-10 scale) and function in chronic low back pain patients 2
- Discontinuation risk: Approximately 13.9-15.2% of patients discontinue duloxetine due to adverse events, compared to 5.4-8.5% with placebo 3, 4, 5
- Common adverse effects: Nausea, dry mouth, fatigue, diarrhea, hyperhidrosis, dizziness, and constipation are the most frequently reported side effects 4
- Elderly patients: Use with particular caution in older adults due to increased fall risk from dizziness and sedation 6
Medication Interactions to Screen
- NSAIDs: While duloxetine can be combined with NSAIDs for chronic low back pain, monitor for increased bleeding risk when used together 2, 6
- Anticoagulants/antiplatelets: Duloxetine may increase bleeding risk when combined with warfarin, aspirin, or other anticoagulants 1
- Alcohol: Advise patients to avoid alcohol due to increased hepatotoxicity risk 1
Screening Before Initiation
- Check current medication list for MAOIs, linezolid, or other serotonergic agents 1
- Assess liver function with baseline transaminases if liver disease is suspected 1
- Evaluate renal function with serum creatinine and estimated GFR 1
- Screen for history of mania or bipolar disorder, as duloxetine may precipitate manic episodes 1
- Assess for suicidal ideation, particularly in younger patients, as antidepressants carry a black box warning for increased suicidality in patients under age 24 1