Chien explains that older, barbiturate-type hypnotics decrease the release of neurotransmitters, thereby depressing the central nervous system and calming the patient. However, barbiturates are both dangerous and addictive. Overuse may cause low blood pressure, breathing difficulties, hypoxemia and acidosis, and can be life-threatening. Hypnotics are even more dangerous when mixed with alcohol, which increases their morbidity rate tenfold.
簡俊生指出，早期巴比妥類安眠藥會降低神經傳導物質的釋出，以抑制中樞神經系統，產生鎮靜作用，但具有成癮性，且安全性較低，過度使用會導致低血壓、呼吸困難、低血氧、酸中毒而危及生命，特別是安眠藥加酒服用，致死率是原來的 10 倍，以致安眠藥中毒一度高居我國中毒排行榜第三位。