The purpose of the study is to evaluate the effectiveness and safety of the use of low-dose nitroglycerin transdermal patches to treat pain and function in chronic tennis elbow.

Chronic tendonitis remains difficult to treat. Nitric oxide has been demonstrated to stimulate tenocytes to proliferate, differentiate and produce matrix components including collagen. Studies have demonstrated that nitroglycerin transdermal patches, which release nitric oxide, reduce pain and increase function in patients with chronic tendonitis. The purpose of the present study is to examine the efficacy of three dose levels of nitroglycerin, compared to placebo, in reducing pain and increasing function in patients with chronic (greater than three months' duration) lateral epicondylitis.

Inclusion Criteria:

• males >18 yr and < 70 yr
• BMI < 38
• chronic lateral epicondylitis (symptomatic > 3 mo)
• pain on provocation >/- 4 on 11 point scale

Exclusion Criteria:

• patients on other pain medications
• bilateral elbow pain
• any humerus elbow or forearm fracture or surgery
• signs of injury other than lateral epicondylitis
• any concomitant disease or pain of the upper extremity
• orthostatic hypotension
• patients taking MAO inhibitors, phosphodiesterase inhibitors, adrenergic agents
• pregnant or nursing women