Kurth TFSGI 1997.

Methods	Randomised double‐blind parallel group study. Randomised by computer generated random number tables with the participants being double‐blinded and the code not being broken until after the database was closed. Intention‐to‐treat data analysis of those that had taken at least one dose and were assessed at baseline and 6 weeks. Multi‐centre, 12 sites Duration: 6 weeks
Participants	161 patients (151 analysed), 5 patients withdrew due to adverse effects. 105 participants were male (65%), mean age 64.5 years, mean disease duration 9.2 years, mean Hoehn and Yahr 'on' 2.15, 'off' 2.81. No baseline mean levodopa dose was stated. Inclusion criteria: Patients with idiopathic PD occurring after age 30, experiencing predictable 'on' response to the first morning dose of levodopa/carbidopa, with at least two episodes of predictable end‐of‐dose 'off' periods. Total 'off' time while awake had to exceed 2 hours per day. Patients were on a stable regime of at least 3 doses per day of standard levodopa/carbidopa. Exclusion criteria: Unpredictable motor fluctuations. Treatment with dopamine agonists, amantadine, anticholinergics, selegiline, carbidopa or levodopa alone, Sinemet CR, Sinemet 1:10 ratio and agents used to treat tremor (primidone, beta‐blockers) was not allowed.
Interventions	Patients received placebo (n=42), 50 mg tid tolcapone (n=41), 200 mg tid tolcapone (n=40), 400 mg tid tolcapone (n=38). Riboflavin (0.5 mg) was included in the placebo tablets to mimic the yellow discolouration in urine that occurs with tolcapone as a harmless side‐effect. No other antiparkinsonian medications were allowed.
Outcomes	UPDRS motor 'Off' time 'On' time 'On' time with dyskinesia Levodopa dose Number of levodopa doses Adverse events UPDRS mentation UPDRS ADL IGA (Welsh QOL paper n=49 SIP PAIS‐SR UPDRS H&Y)
Notes	TOLCAPONE
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Low risk	A ‐ Adequate