Comprehensive Nursing Pharmacology Q 128

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The nurse teaching a client who will receive thiopental (Pentothal) as an anesthetic explains what common adverse effects might occur?

  

     A. Headache

     B. Emergence delirium

     C. Nausea and vomiting

     D. Paralysis

    

    

Correct Answer: B. Emergence delirium

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Emergence delirium could occur postoperatively, and is characterized by hallucinations, confusion, and excitability. Barbiturates are a group of sedative-hypnotic medications used for the treatment of seizure disorder, neonatal withdrawal, insomnia, preoperative anxiety, induction of coma for increased intracranial pressure. They are also useful for inducing anesthesia.

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Option A: Drug interactions with oral barbiturates have been a frequent topic of research. Phenobarbital is known to be an inducer of the cytochrome enzyme system, specifically the CYP1A2, 2B6, 2C9, and 3A4/5 isozymes that will reduce the efficacy of warfarin, steroids, oral contraceptives, psychoactive, immunosuppressants. Phenobarbital will also lower the plasma concentrations of other antiepileptic drugs such as lamotrigine, oxcarbazepine, phenytoin, tiagabine, and valproate.

Option C: Overdose of phenobarbital symptoms includes CNS depression, respiratory failure, and hemodynamic instability. No antidote exists. Treatment of an overdose includes supportive care, activated charcoal (if taken orally), and urinary alkalinization.

Option D: Phenobarbital has a narrow therapeutic range of 10 to 30 mg/L, with 80mg/L reported as being fatal.[38] A Cochrane review found no clear evidence of a benefit to routine serum monitoring of drug concentrations for antiepileptic drugs. Dose titration to control seizures was found to be effective.

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