Comprehensive Nursing Pharmacology Q 278
Mr. Jessie Ray, a newly admitted patient, has a seizure disorder which is being treated with medication. Which of the following drugs would the nurse question if ordered for him?
A. phenobarbital (Solfoton) 150 mg hs
B. amitriptyline (Elavil), 10 mg QID
C. valproic acid (Depakote), 150 mg BID
D. phenytoin (Dilantin), 100 mg TID
Correct Answer: B. amitriptyline (Elavil), 10 mg QI
Elavil is an antidepressant that lowers the seizure threshold, so would not be appropriate for this patient. The other medications are anti-seizure drugs. The risk of epilepsy/seizures is significantly increased for all classes of antidepressants. There is a need for individual risk-benefit assessments in patients being considered for antidepressant treatment, especially those with ongoing mild depression or with additional risk factors.
Option A: Sedative-hypnotic agents include a class of drugs called barbiturates. Phenobarbital’s mechanism of action increases the amount of time chloride channels are open, which in turn depresses the central nervous system. This action occurs by acting on GABA-A receptor subunits. When phenobarbital binds to these receptors, the chloride ion gates open and stay open, allowing a steady flow of these ions into neuronal cells. This action hyperpolarizes the cell’s membrane, thereby increasing the threshold for the action potential. This increase in action potential is the reason why this drug is effective in the treatment of seizures.
Option C: Valproic acid is a branched, and short-chain fatty acid is a derivative of naturally occurring valeric acid. Valproic acid’s primary use is as an anti-seizure medication, as well as in migraine, bipolar, mood, and anxiety disorders. Valproic acid exhibits its pharmacologic effects in a couple of ways, such as by acting on GABA (? aminobutyric acid) levels in the CNS, blocking voltage-gated ion channels, and also by inhibiting histone deacetylase. Impaired GABAergic inhibitory activity is the established pathophysiology of seizure initiation and propagation, given that controlling this pathway is a potential target for antiepileptic drugs.
Option D: The FDA approved phenytoin in 1939 for the treatment of epilepsy. Despite its narrow therapeutic index, the drug has seen robust use in the treatment of generalized tonic-clonic seizures, complex partial seizures, status epilepticus, trigeminal neuralgia, and behavior disorders. Phenytoin is a hydantoin derivative, a first-generation anti-convulsant drug that is effective in the treatment of generalized tonic-clonic seizures, complex partial seizures, and status epilepticus without significantly impairing neurological function.