Study	Reason for exclusion
Alfonzo Guerra 1980	No placebo only arm during randomization (compared methyldopa versus clonidine versus clonidine and thiazide diuretic)
Anonymous 1986	No methyldopa arm (trial focused on enalapril versus placebo)
Aoki 1970	No placebo only arm during randomization (compared methyldopa versus hydralazine in patients already receiving hydrochlorothiazide)
Avigdor 1983	Methyldopa, placebo, debrisoquine, and propranolol were added randomly to patients already receiving the diuretic mefruside
Bayliss 1962	Not a randomized study comparing methyldopa versus placebo
Beanlands 1978	No placebo only arm during randomization (compared methyldopa versus pindolol)
Belleau 1977	No placebo only arm during randomization (compared methyldopa versus debrisoquine in patients already receiving hydrochlorothiazide)
Bradley 1977	No placebo only arm during randomization (compared methyldopa versus prazosin)
Bune 1981	No placebo only arm during randomization (compared methyldopa versus guanfacine in patients already receiving bendrofluazide)
Cannon 1962	Not a randomized study comparing methyldopa versus placebo
Co‐operative 1973	Treatment groups received varying combinations of methyldopa, bendrofluazide, and/or debrisoquine (could not differentiate patients who received only methyldopa and therefore cannot compare against patients who received only placebo)
Corea 1983	No placebo arm during randomization (both treatment groups received methyldopa)
Daley 1962	Not a randomized study comparing methyldopa versus placebo
De Divitiis 1981	No placebo only arm during randomization (compared methyldopa versus atenolol)
Deschamps 1992	Patients were not diagnosed with essential hypertension (trial of methyldopa in patients with pregnancy‐related hypertension)
Dollery 1962	No placebo only arm during randomization (all treatment groups received methyldopa)
Dunn 1978	Primarily assessed effect of antihypertensives to maintain blood pressure in presence of external stressor (no outcomes of interest) Unknown if randomized trial
Frederiksen 1974	Patients were not diagnosed with essential hypertension (trial of methyldopa in patients with angina)
Glassock 1982	No placebo only arm during randomization (compared methyldopa vs pindolol)
Glazer 1975	No placebo only arm during randomization (compared methyldopa versus guanethidine in patients already receiving hydrochlorothiazide)
Gonasun 1982	No placebo only arm during randomization (compared pindolol versus methyldopa)
Guidi 1981	No placebo only arm during randomization (compared methyldopa versus metoprolol in patients already receiving chlorthalidone)
Hamilton 1963	No placebo only arm during randomization (all patients received methyldopa)
Horwitz 1966	Not a randomized study comparing methyldopa versus placebo
Innes 1992	No placebo only arm during randomization (compared methyldopa versus labetalol) Patients were not diagnosed with essential hypertension (trial of methyldopa in patients with hypertension secondary to various renal disorders)
Irvine 1962	Not a randomized study comparing methyldopa versus placebo
Johnson 1966	No placebo only arm during randomization (all patients received methyldopa)
Klapper 1964	Not a randomized study comparing methyldopa versus placebo
Kuokkanen 1979	No placebo only arm during randomization (compared methyldopa versus prazosin)
Kuschke 1963	Not a randomized study comparing methyldopa versus placebo
Levine 1968	No placebo only arm during randomization (compared methyldopa versus guanethidine)
Masso 1979	No placebo only arm during randomization (compared methyldopa versus bromazepam)
McAreavey 1983	Methyldopa or placebo were added in patients already receiving atenolol and bendrofluazide if blood pressure was not controlled
McAreavey 1984	Methyldopa or placebo were added in patients already receiving atenolol and bendrofluazide if blood pressure was not controlled
Murad 1991	No placebo only arm during randomization (compared methyldopa versus lisinopril)
Oates 1960	Not a randomized study comparing methyldopa versus placebo
Oates 1965	No placebo only arm during randomization (compared methyldopa versus guanethidine versus pargyline)
Okanga 1978	No placebo only during randomization (compared methyldopa versus atenolol)
Onesti 1962	No placebo only arm during randomization (all patients received methyldopa)
Sermswan 2003	Methyldopa or placebo were added in patients already receiving three other antihypertensives (e.g.. thiazide diuretic, calcium channel blocker, beta blocker, ACE inhibitor)
Smirk 1963	Not a randomized study comparing methyldopa versus placebo
Smith 1966	No placebo only arm during randomization (compared methyldopa versus methyldopa and thiazide versus thiazide and herbal product)
Wright 1982	Some trial patients continued with diuretic therapy (bendrofluazide) during the study period. Cannot distinguish results details relating to patients receiving only methyldopa versus those who received methyldopa and diuretic therapy. Duration of effect of single dose of methyl dopa was studied in a double blind cross over study in 10 patients who were selected because methyldopa had proven to be effective and well tolerated in these patients. Methyldopa was given once daily up to 4 g as a single dose either in the morning or evening and compared to placebo. At the end of every 2 weeks BP was measured every hour from 08.30h to 22.30 h.