Clinical presentation and laboratory determination of Phenobarbital overdose

Abstract

Objective: Barbiturates as hypnotic drugs are widely used in medicine. They act as sedative or analgesic and are used to control seizure disorders. References show that the number cases of poisoning by this drug is very high. Rapid determination of Phenobarbital in blood of poisoned patients can lead to good treatment approaches. Several laboratory methods are currently available for the detection of barbiturates, but few are suitable for emergency use. Methods: In this study we evaluated the use of a modified uv-spectrophotometric method in determination of Phenobarbital levels in blood of poisoned patients. This method is based on differential spectrums of Phenobarbital in two alkaline environments. We compared analytical results obtained by this method with previous acceptable spectrophotometry method. Findings: There is good correlation (r=0.998) between these two methods. Our results indicate that the procedure time was approximately 45 minutes, sensitivity 2 mg/ml, precision 7.034%, recovery 99.1%. The clinical signs and symptoms and medical examinations of poisoned patients are also recorded. Our results indicated that Phenobarbital overdose is mainly manifested by sedation, tachycardia, neurologic disturbances, hypotension, myosis and hypoxemia. All of the patients had attempted suicide and were discharged alive from the hospital. We found good correlation (r=0.945) between increase in pulse rate and blood Phenobarbital levels. It may be of value in diagnosis of the severity of Phenobarbital overdose. We could not find any correlation between blood Phenobarbital levels and the rate of consciousness or grade of coma. Conclusion: In conclusion, the use of this method for an emergency determination of phenobarbital overdose in toxicology centers is recommended.

Keywords

• phenobarbital
• overdose
• determination
• uv spectrophotometry