根据《柯林斯英汉双解大词典 》：
N-COUNT A tranquilizer is a drug that makes people feel calmer or less anxious. Tranquilizers are sometimes used to make people or animals become sleepy or unconscious. 镇静剂[1]
Injection tranquilizer 镇静剂注射
sedative tranquilizer 镇静剂
major tranquilizer 强安定药 ; 重安神剂
Administration tranquilizer 镇静剂投药
strong tranquilizer 强镇静剂
Tranquilizer Dart 麻醉镖
horse tranquilizer 马安定剂
ataractic tranquilizer 安定剂
minor tranquilizer 弱安定剂 [1]
If a tranquilizer is prescribed, be sure your physician informs you of its possible side effects, such as addiction.
如果开了镇静剂，一定要让医生告诉你它可能带来的副作用，例如上瘾。
Pic.15 A tiger with a tranquilizer dart stuck in its back walks inside the Assam State Zoological cum Botanical Garden in Guwahati January 30, 2010.
图15 2010年1月30日，在高哈蒂的阿萨姆省动植物园，一只被麻醉镖扎中背部的老虎在走动。
State medical records indicate that large concentrations of the tranquilizer Valium and the sleep aid Restoril were in his system that night, among other prescription drugs.
当晚的州医疗记录显示在他体内除了有其他处方药外，还有大剂量的镇静剂安定和助睡眠药物替马西泮。[1]