What is a suitable medication for a 75-year-old patient with shoulder pain and normal renal (kidney) function?

Acetaminophen is the Best First-Line Medication for Shoulder Pain in a 75-Year-Old with Normal Kidney Function

Acetaminophen (up to 3 grams per day) is the most appropriate first-line medication for a 75-year-old patient with shoulder pain who has normal kidney function, due to its favorable safety profile and effectiveness for mild to moderate pain. 1, 2

First-Line Treatment Options

• Acetaminophen should be considered the preferred first-line pharmacologic treatment for mild to moderate shoulder pain in older adults, with a recommended dosage of up to 3 grams per day (reduced from the standard 4 grams to minimize risk of hepatotoxicity in elderly patients) 1, 2
• Acetaminophen provides effective pain relief while avoiding the gastrointestinal, renal, and cardiovascular risks associated with NSAIDs, making it particularly suitable for elderly patients 1, 3
• For this 75-year-old patient, starting with regular acetaminophen dosing (e.g., 650-1000 mg every 6-8 hours, not exceeding 3 grams daily) is recommended 2, 3

Safety Considerations for Elderly Patients

• Acetaminophen is considered safer than NSAIDs for elderly patients due to minimal renal effects, which is important even though this patient has normal kidney function 2, 3
• NSAIDs carry significant risks in elderly patients, including gastrointestinal bleeding, acute kidney injury, and cardiovascular complications, even with short-term use 1, 4
• The American Geriatrics Society recommends monitoring total acetaminophen intake carefully, especially when using combination products, to prevent exceeding the daily maximum dose 2

If Acetaminophen Is Insufficient

If acetaminophen alone does not provide adequate pain relief after a trial of 1-2 weeks:

• Consider adding a topical NSAID (such as diclofenac gel) which provides localized pain relief with minimal systemic absorption 1
• For moderate to severe pain unresponsive to acetaminophen, tramadol may be considered as it has reduced respiratory and gastrointestinal effects compared to other opioids 1
• If an oral NSAID is necessary despite risks, use the lowest effective dose for the shortest duration possible, and consider adding a proton pump inhibitor to reduce gastrointestinal risks 1

Specific Considerations for Shoulder Pain

• For shoulder pain specifically, acetaminophen has shown effectiveness in providing pain relief, though some studies suggest ibuprofen may provide better functional improvement 5, 6
• If the shoulder pain is inflammatory in nature and acetaminophen is insufficient, a short course of an NSAID like naproxen could be considered, but with careful monitoring for adverse effects 4, 5
• For localized shoulder pain, consider adding non-pharmacological approaches such as physical therapy, proper positioning, and supportive devices alongside medication 1

Common Pitfalls to Avoid

• Avoid exceeding the recommended maximum daily dose of acetaminophen (3 grams for elderly patients) as higher doses increase the risk of hepatotoxicity 2, 3
• Do not use NSAIDs as first-line therapy in elderly patients due to their significant risk profile, despite their anti-inflammatory properties 1, 4
• Be aware of "hidden sources" of acetaminophen in combination medications (especially cold remedies and opioid combinations) that could lead to unintentional overdose 1, 2
• Avoid long-term use of any pain medication without regular reassessment of effectiveness and side effects 1

In conclusion, acetaminophen represents the safest and most appropriate first-line medication for this 75-year-old patient with shoulder pain and normal kidney function, with careful consideration of dosage adjustments for age.