Crosby 1996.

Methods	Randomised placebo‐controlled trial
Participants	Participants: 44; mean age 34 years; male 79.5%; African American 57%; married 34% Education: less than high school 14%, high school 70%, college 15%: current employed 59% Reporting cocaine use: 100% Route of cocaine ingestion: intranasal 4.5%, smoking 93%, intravenous 2%; cocaine use in the past 30 days mean 11.7 days; number of previous treatments mean 1.5; lifetime cocaine abuse mean 90 months; alcohol use to intoxication in the past 30 days: 3.0 days Inclusion criteria: 18 years old, fulfilling DSM‐IV criteria for current cocaine abuse/dependence Exclusion criteria: current clinical unstable medical illness or history of seizure disorder, history of head trauma resulting in brain injury or history of heart block or other cardiac disorder; lifetime psychiatric diagnosis of mental retardation precluding the ability to read, understand and complete written tests; organic brain syndrome with cognitive impairment; schizophrenia, bipolar affective disorder, schizoaffective disorder, suicidal risk, pregnancy, use of any psychiatric agent or mood‐altering medication in the previous 6 weeks
Interventions	(1) phenytoin 100 mg/d, 20 participants; (2) placebo, 24 participants Outpatient Duration: 12 weeks Country of origin: USA
Outcomes	Dropout; Use of cocaine; Craving; Side effect; Compliance
Notes	Source of funding and conflict of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Information not reported
Allocation concealment (selection bias)	Unclear risk	Information not reported
Blinding of participants and personnel (performance bias) objective outcomes	Low risk	Study declared as double‐blind Quote: "subjects were seen weekly by a trained psychotherapist blinded to treatment condition"
Blinding of participants and personnel (performance bias) subjective outcomes	Low risk	Study declared as double‐blind Quote: "subjects were seen weekly by a trained psychotherapist blinded to treatment condition"
Blinding of outcome assessment (detection bias) objective outcomes	Low risk	Study declared as double‐blind Quote: "all clinical rating were made by trained chemical dependency counsellors who were blinded to treatment condition"
Blinding of outcome assessment (detection bias) subjective outcomes	Low risk	Study declared as double‐blind Quote: "all clinical rating were made by trained chemical dependency counsellors who were blinded to treatment condition"
Incomplete outcome data (attrition bias) All outcomes	High risk	Quote: "16 subjects, 9 receiving phenytoin (31%) and 7 receiving placebo (23%) failed to return to visit 1 and were eliminated from the analysis. 12 subjects completed the twelve weeks protocol, 6 receiving phenytoin (20.7%) and 6 (19.4%) receiving placebo"
Selective reporting (reporting bias)	Low risk	Study protocol is not available, but published reports include all expected outcomes, including those that were prespecified in the Methods section