What is the recommended treatment with naproxen (nonsteroidal anti-inflammatory drug (NSAID)) for a patient with neck muscle pain, considering their age, medical history, and kidney function (renal function)?

Naproxen for Neck Muscle Pain

Naproxen can be used for acute neck muscle pain in otherwise healthy adults at 500 mg initially, followed by 250-500 mg every 8-12 hours, but should be avoided entirely in elderly patients (≥60 years), those with renal impairment (creatinine clearance <30 mL/min), cardiovascular disease, or gastrointestinal risk factors—in these populations, acetaminophen up to 3 grams daily or topical NSAIDs are safer alternatives. 1, 2

Patient Risk Stratification

Before prescribing naproxen, assess the following critical risk factors:

High-Risk Patients Who Should NOT Receive Naproxen:

• Age ≥60 years: NSAIDs caused 23.5% of hospitalizations for adverse drug reactions in older adults, with gastrointestinal toxicity increasing in frequency and severity with age 3
• Renal impairment: Creatinine clearance <30 mL/min is an absolute contraindication; NSAIDs cause decreased renal perfusion, volume-dependent renal failure, interstitial nephritis, and nephrotic syndrome 1, 2
• Cardiovascular disease or risk factors: NSAIDs increase risk of hypertension, myocardial infarction, and stroke 3
• History of peptic ulcer disease or GI bleeding: These patients have a >10-fold increased risk of GI bleeding with NSAIDs 2
• Congestive heart failure or cirrhosis: These patients depend on prostaglandin-mediated renal perfusion, which NSAIDs inhibit 1, 2
• Concurrent use of anticoagulants, aspirin, corticosteroids, or SSRIs: These combinations significantly increase bleeding risk 3, 2

Treatment Algorithm for Neck Muscle Pain

For Low-Risk Patients (Age <60, Normal Renal Function, No GI/CV Risk):

First-line: Naproxen 500 mg initially, then 500 mg every 12 hours or 250 mg every 6-8 hours as needed 2

• Maximum initial daily dose: 1250 mg 2
• Maximum ongoing daily dose: 1000 mg 2
• Duration: Use the lowest effective dose for the shortest duration possible 2
• Onset of pain relief: Within 1 hour 2

For High-Risk Patients (Age ≥60, Renal Impairment, GI/CV Risk):

First-line: Acetaminophen 650 mg every 4-6 hours (maximum 3 grams daily in elderly or those with renal impairment) 1, 3

• Acetaminophen provides comparable pain relief to NSAIDs without gastrointestinal, cardiovascular, or nephrotoxic effects 1

Second-line: Topical NSAIDs (e.g., diclofenac gel) applied to the neck area 3, 1

• Provides effective analgesia with minimal systemic absorption and negligible renal effects 1
• Efficacy similar to oral NSAIDs with adverse event profile similar to placebo 1

Third-line: If systemic NSAID absolutely necessary, use the lowest dose for ≤5 days with strict monitoring 3

Mandatory Monitoring if Naproxen is Used

Baseline Assessment:

• Blood pressure 3
• BUN and creatinine 3
• Liver function tests (alkaline phosphatase, LDH, AST, ALT) 3
• Complete blood count 3
• Fecal occult blood 3

Ongoing Monitoring:

• Repeat all baseline tests every 3 months if continued use 3

Discontinuation Criteria:

• BUN or creatinine doubles 3
• Hypertension develops or worsens 3
• Liver function tests increase >3 times upper limit of normal 3
• Any gastric upset, nausea, or signs of GI bleeding 4

Critical Pitfalls to Avoid

• Never combine naproxen with ACE inhibitors, ARBs, and diuretics: This "triple whammy" creates high risk for acute kidney injury 1
• Never use in pregnancy, especially late pregnancy: May cause premature closure of ductus arteriosus, persistent pulmonary hypertension, and renal dysfunction in the fetus 2
• Never assume COX-2 inhibitors are safer for kidneys: They carry identical nephrotoxicity risk as traditional NSAIDs 1
• Never use two NSAIDs simultaneously: This increases toxicity without improving efficacy 4
• Never continue if gastric symptoms develop: 80% of patients who develop serious upper GI events on NSAIDs had no prior warning symptoms 2

Special Populations

Elderly Patients:

• The unbound plasma fraction of naproxen increases in elderly patients, requiring dose reduction 2
• Start with acetaminophen instead; if NSAID absolutely necessary, use lowest dose and monitor closely 3, 1

Renal Impairment:

• Naproxen is contraindicated in moderate to severe renal impairment (CrCl <30 mL/min) 2
• If mild impairment, consider dose reduction and ensure adequate hydration 2, 1

Hepatic Impairment:

• Use lower doses and monitor liver function closely 2

Adjunctive Therapies

Naproxen should be combined with non-pharmacologic approaches for optimal outcomes:

• Physical therapy 3, 5
• Heat therapy (low-level continuous heat improves pain relief and range of motion) 5
• Rest and activity modification 6

For severe muscle spasm, consider adding a muscle relaxant (e.g., cyclobenzaprine) to naproxen, though this increases drowsiness 6