Phase 1/2 Prospective Double-blind, Placebo-controlled Randomized Clinical Trial Using Losartan to Treat Grade II and III Hamstring Strains

Inclusion Criteria

1. 18 years of age and older;

2. Have had grade II or III hamstring injury within the 7 days prior to enrollment;

3. Greater than 100 hours per year in Level I (football, basketball, or soccer) or Level
II (racquet sports, skiing, manual labor occupations/heavy physical work) and
activities that require running and sprinting;

4. Agree to take study medications as prescribed

Exclusion Criteria:

1. Have had previous hamstring injury on the same side or chronic symptoms;

2. Have an injury that requires surgical intervention (e.g. avulsion with associated bony
involvement, grade III complete tears);

3. Have concurrent lower back symptoms;

4. Pregnant or breast feeding;

5. Is a smoker;

6. Has contraindications for Losartan therapy (hypersensitivity to Losartan, hepatic
involvement);

7. Currently use angiotensin I converting enzyme inhibitor (ACEI)/ Angiotensin II
receptor blocker (ARB);

8. Have hypertension (blood pressure greater than or equal to 140 mmHg systolic pressure
or greater than or equal to 90 mmHg diastolic pressure);

9. Have hypotension (blood pressure less than or equal to 90 mmHg systolic pressure or
less than or equal to 60 mmHg diastolic pressure);

10. Have orthostatic hypotension defined as a drop in systolic pressure greater than or
equal to 2 0mmHg or a drop in diastolic blood pressure greater than or equal to 10
mmHg or reports of lightheadedness or dizziness upon standing;

11. Have diabetes mellitus, cardiovascular, renal or hepatic co-morbidities;

12. Have contraindications for MRI - including:

- Prior surgery for an aneurysm;

- Have cardiac pacemaker;

- Have metal fragments in the eyes, brain, or spinal cord from shrapnel, metal
work, or welding;

- Have surgical implants, such as ear implant or neurostimulator;

- Have a history of claustrophobia;

- Have a history of not tolerating previous MRI scans without medication