Study	Reason for exclusion
Burke 2001	Washout period was only 10 days.
Digiesi 1994	No placebo control.
Drzewoski 1981	No placebo control.
Eghtesadi 2012	Only an abstract available
Folkers 1981	No placebo control.
Hata 1977	Trial is not randomized, no parallel placebo group. Washout period is only 1 to 2 weeks.
Hodgson 2002	Included mostly patients with normal blood pressure, baseline BP ranged from 127/75 to 136/80 mm Hg and therefore, did not meet hypertension criteria.
Langsjoen 1994	No placebo control.
Shah 2007	Treatment period was less than 3 weeks (longest post‐dose period was 8 hours).
Shcherbakova 2010	Not a placebo controlled trial
Singh 1999	Not likely a double blinded trial as different treatment groups met separately. Changes in antihypertensive medications were allowed and occurred during the trial.