A Study Evaluating the Efficacy and Safety of Pregabalin Against Frequent Muscle Cramp in Patients With Liver Cirrhosis

The investigators are planning to recruit patients with liver cirrhosis and muscle cramp, and collect the baseline clinical and laboratory data during the 4-week run-in period for each subject. After a run-in period, there will be the second step of patient selection to achieve a more homogenous study population. Then, patients will be randomly allocated into the treatment (pregabalin) and placebo (dummy) arms, by a web-based randomization program. After a treatment period (75 mg twice daily during the first 1 week as titration, 150 mg twice daily for 4 weeks as standard dose), the investigators will gather further study information of a standard dose period (150mg twice daily for 4 weeks) from the target population and the study subjects will enter the 1-week tapering period (75mg twice a day) to discontinuation. The primary outcome will be the difference in the frequency of muscle cramps between the run-in and treatment phases. The investigators also intend to assess the response rate, defined as the proportion (%) of patients showing ≥50% reduction in the number of muscle cramps, mean change in the average pain intensity, mean change in the score of the Short Form 36 (SF-36, QualityMetric) health survey questionnaire, mean change in the frequency of muscle cramps during sleep, and mean change in the average cramp threshold frequency by the neurophysiologic study (nerve excitability test) and analyze the reasons for drop-out cases.