Chloral Hydrate 水合氯醛
（Journal of the Nippon Hospital Pharmacists Association:病院薬学 26(2) pp.198-201 20000410 ）
The stability of chloral hydrate (CH) in aqueous solutions for rectal use was studied. The CH solution (5%) was stored in glass containers at the volume of 4 mL for 90 days at 25℃ (under 480 lux and In the dark) and 4℃ (in the dark). To observe the stability in daily use, the CH solution was also stored in glass or polypropylene bottles for dispensing at the volume of 100 mL for 90 days at 4℃ in the dark. The stability was evaluated by pH variation and the amount of CH in the solution. In both CH solutions stored in glass containers at the volume of 4 mL and glass bottles' at the volume of 100 mL for dispensing at 4℃ in the dark for 30 days, there was very little pH change in the solution. Under other conditions, a significant decrease in the pH was observed at the CH solutions stored for 30 days. However, the CH amounts In the solutions remained more than 95% at least 90 days under all tested conditions. We therefore conclude that 5% CH solution is applicable for rectal use for at least 90 days, if it is stored in glass bottles for dispensing at 4℃ in the dark.
Overdosage. The general management of poisoning with cloral hydrate resembles that for barbiturates (see Treatment of Adverse Effects, under Amobarbital, p.962). Activated charcoal
may be given orally to adults and children within 1 hour of ingestion of more than 30 mg/kg, provided that the airway can be protected;the value of gastric decontamination for overdose is uncertain.
Of 76 cases of cloral hydrate poisoning reported to the UK National Poisons Information Service (NPIS), 47 were severe.
1 Of 39 adults, 12 had cardiac arrhythmias including 5 with cardiac arrest. Antiarrhythmic drugs were recommended unless obviously contra-indicated. Haemoperfusion through charcoal
or haemodialysis was recommended for patients in prolonged coma. Cardiac arrhythmias and CNS depression were also major features of 12 cases of cloral hydrate overdosage reported from
2 Lidocaine was not always successful in controlling arrhythmias, but propranolol was successful in all 7 patients in whom it was used. It was noted that resistant arrhythmias, particularly
ventricular fibrillation, ventricular tachycardia, and supraventricular tachycardia, were the usual cause of death in patients who had taken an overdosage of cloral hydrate. Although there had been no controlled studies of antiarrhythmic therapy in overdosage with cloral hydrate, the successful use of beta blockers appeared to be a recurring feature in reports in the literature.
Indeed, the UK NPIS notes that tachyarrhythmias usually respond readily to an intravenous beta blocker such as esmolol or propranolol.
3.Giving flumazenil produced an increased level of consciousness,pupillary dilatation, and return of respiratory rate and blood pressure towards normal in a patient who had taken an overdosage of
1. Wiseman HM, Hampel G. Cardiac arrhythmias due to chloral hydrate poisoning. BMJ 1978; 2: 960.
2. Graham SR, et al. Overdose with chloral hydrate: a pharmacological and therapeutic review. Med J Aust 1988; 149: 686–8.
3. Donovan KL, Fisher DJ. Reversal of chloral hydrate overdose with flumazenil. BMJ 1989; 298: 1253.