Seizure Meds

Question 1

phenobarbital

Answer 1

Pharmacologic: Barbiturates

phenobarbital (Luminal)
Therapeutic: antiseizure drug; sedative

Indications:
anticonvulsant (primary use)
sedative
preanesthetic agent

DO NOT use for pain relief, may increase sensitivity to pain

Alert:
high abuse potential
schedule IV drug

when therapy is discontinued, the dose should be tapered and do not stop abruptly
→ risk for seizures*

ADR:
respiratory depression

Interactions:
should not be combined with other CNS depressants

Question 2

lorazepam

Answer 2

Pharmacologic: Benzodiazepines

diazepam (Valium)
lorazepam (Ativan)

Indications/Uses:
sedation
antianxiety
anticonvulsant effects - primarily: status epilepticus

Black box warning: states that concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death
Know: IV administration monitor respiration every 15 minutes - risk for respiratory depression

Overdose: flumazenil (Romazicon)
specific for benzodiazepine overdose (not other classes)

CNS depressant
sedation
do not drive or operate heavy machinery

Administration/Teaching:
due to tolerance and dependence, use of diazepam is reserved for short-term seizure control or for status epilepticus

about 4 weeks may develop tolerance
do not increase/double dose
contact HCP

Question 3

gabapentin (Neurontin, others)

Answer 3

Indications/Uses:
partial seizures
neuropathic pain (e.g., diabetic neuropathy)
also used for restlessness, anxiety

ADR:
CNS Depression
Dizziness, somnolence, ataxia
Taper dose; do not stop abruptly

Check:
renal labs
assess LOC
assess respiration rate - hold if respiratory depression

Question 4

phenytoin

Answer 4

phenytoin (Dilantin, Phenytek)
Therapeutic Class: antiseizure drug, antidysrhythmic drug
Pharmacologic Class: hydantoin; sodium influx-suppression drug

Uses:
tonic-clonic (grand mal) and psychomotor (temporal lobe) seizures
most types of seizures EXCEPT absent seizures
Prevention and Tx of seizures occurring during or following neurosurgery

Black Box Warning:
IV Rate - rate of administration should not exceed 50 mg/min in adults and 1 to 3 mg/kg/min (or 50 mg per minute, whichever is slower)
Abrupt discontinuation can cause status epilepticus

Caution/ADR:
CNS depression
can cause dysrhythmias
Contraindications:
heart block, sinus bradycardia,
rash, seizures r/t hypoglycemia
Administration
Know: soft tissue irritant
DO NOT give IM
Avoid hand veins
??Inject in large veins or central venous catheters?

Question 5

valproic acid (Depakene, others)

Answer 5

Therapeutic Class: antiseizure drug
Pharmacologic Class: Valproate
Uses: many types of epilepsy

Black Box Warning:
hepatic failure esp. in children under 2 y.o. -
check liver labs prior to admin. and specific intervals during first 6 mo
contraindicated with liver disease, pancreatitis, bleeding dysfunction
can produce life-threatening pancreatitis
can produce teratogenic effects including spina bifida

Other Caution/ADR:
begin with lowest dose
GI irritant
Know: increased risk of bleeding, prolongued bleeding time
Check PTT and H&H
Concomitant warfarin, aspirin, or alcohol use can cause severe bleeding
(CNS depressant) - sedation,, drowsiness
Administration/Teaching:
IF it is in form of syrup - DO NOT mix with carbonated beverages - it will cause immediate release of drug

do not mix …
Interacts with many drugs:
aspirin, cimetidine, erythromycin,…may increase valproic acid toxicity
Valproic acid increases serum phenytoin and phenobarbital levels
CNS Depression
Alcohol, benzodiazepines, other CNS depressants potentiate CNS depressant action