EVIDENCE-BASED ANSWER:
Topical nitrates provide short-term relief with some side effects, especially headache. Topical nitroglycerin (NTG) patches improve subjective pain scores by about 30% and range of motion over 3 days in patients with acute shoulder tendinopathy (strength of recommendation [SOR]: C, small randomized controlled trial [RCT] with no methodologic flaws).
NTG patches, when combined with tendon rehabilitation, improve subjective pain ratings by about 30% and shoulder strength by about 10% in patients with chronic shoulder tendinopathy over 3 to 6 months, but not in the long term (SOR: C, RCTs with methodologic flaws). They improve pain and strength 15% to 50% for chronic extensor tendinosis of the elbow over a 6-month period (SOR: C, small RCT with methodologic flaws).
NTG patches used without tendon rehabilitation don’t improve pain or strength in chronic lateral epicondylitis over 8 weeks (SOR: C, RCT).
Topical NTG patches commonly produce headaches and rashes (SOR: B, multiple RCTs).
EVIDENCE SUMMARY
A small RCT found that NTG therapy improved short-term pain and joint mobility in patients with acute supraspinatus tendinitis.1 Investigators randomized 10 men and 10 women with acute shoulder tendonitis (fewer than 7 days’ duration) to use either 5-mg NTG patches or placebo patches daily for 3 days. Patients rated pain on a 10-point scale, and investigators measured joint mobility on a 4-point scale.
After 48 hours of treatment, NTG patches significantly reduced pain ratings from baseline (from 7 to 2 points; P<.001), whereas placebo didn’t (6 vs 6 points; P not significant). NTG patches also improved joint mobility from baseline (from 2 points “moderately restricted” to .1 points “not restricted”; P<.001), but placebo didn’t (1.2 points “mildly restricted” vs 1.2 points; P not significant). The placebo group had less pain and joint restriction than the NTG group at the start of the study. Two patients reported headache 24 hours after starting treatment.