Mroczek 1974.

Methods	Single‐centre study Randomization: "Random assignment was made to one of the three treatment groups by a computer using a pseudo‐random number generator assigned to the list of drugs." Blinding: "The double blind aspect of the study was maintained by having the evaluating physician indicate dosage increases by prescription to an experienced drug monitor who was acquainted with the study design, the patient drug assignment, and dosage schedule."; "Placebo...was supplied in identical matching capsules to prazosin and methyldopa." Withdrawals: not reported Lost to follow‐up: not reported Treatment duration: blood pressures measured at two week intervals Analysis type: not reported
Participants	Geographic region: not reported Study setting: not reported N=60 Age range: Methyldopa arm (47.2 +/‐ 9.4), Placebo arm (45.7 +/‐ 11.1), Prazosin arm (44.7 +/‐ 9.9) Gender: 8 males, 52 females Race: all blacks Blood pressure at entry: Methyldopa arm ‐ Supine (160/101), Standing (168/106); Placebo arm ‐ Supine (156/100), Standing (163/104); Prazosin arm ‐ Supine (156/101), Standing (164/105) Co‐morbid conditions: not reported Inclusion criteria: essential hypertension; diastolic blood pressure greater than 95 mm Hg Exclusion criteria: not reported
Interventions	All anti‐hypertensives discontinued and replaced with single blind placebo for an eight week washout period before trial entry. Methyldopa (average dose 1190.5 mg +/‐ 524 mg daily) x 12 weeks (N=21) Placebo x 12 weeks (N=18) Prazosin x (average dose 16.5 mg +/‐ 4.4 mg daily) 12 weeks (N=21)
Outcomes	Supine blood pressure Standing blood pressure Side effects (postural dizziness, headache, other)
Notes	Assessment of medication compliance: medications were dispensed as 14‐day supplies and patients returned with medication bottles for capsule counts (level of achievement of medication compliance not reported) Final number of patients included in each arm when reporting results: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	"Random assignment...by computer using a pseudo‐random number generator assigned to the list of drugs."
Allocation concealment?	Unclear risk	Unclear
Blinding? All outcomes	Low risk	Double blind
Incomplete outcome data addressed? All outcomes	Unclear risk	Unclear ‐ final number of patients in each treatment arm was not reported in results
Free of selective reporting?	Low risk	Reported on all pre‐specified outcomes of interest