1Valproic Acid
Indications
Broad Spectrum Agent
Complex Partial Seizures
Absence seizures
Bipolar Disorder
Migraine Prophylaxis
MOA
Modulate sodium channels
Teratogenic
2Valproic Acid Efficacy
most effective AED for generalized tonic-clonic seizures
3VPA Therapeutic Concentration
50-150 mg/L
4VPA DDI
• Hepatic metabolism (potent inhibitor and highly protein bound)
• VPA: decreases the PHT total, CBZ total, TPM and TGB (small amount)
• VPA: increases the PHT unbound, CBZ unbound, CBZ epoxide, PB, felbamate, LTG,
ethosuximide, tiagabine unbound, ZNS
• Inducers (CBZ, PHT, PB) decrease VPA concentrations
5If switching from delayed release (DR) to extended-release (ER) VPA formulation, consider
a slight dose increase due to bioavailability differences
6Carbamazepine (CBZ)
MOA: fast sodium channel blocker
• CI: TCA or CBZ sensitivity/allergy, history of bone marrow suppression, concomitant nefazodone
Boxed Warnings:
•SJS/TEN: 10-fold increase risk in individuals of Asian descent (test for HLA-B*1502
allele)
•Aplastic anemia/agranulocytosis: periodic CBC & d/c if evidence of bone
marrow suppression and/or WBC or ANC < 3000/mm3 or 1500/mm3, respectively
•Drug reaction with eosinophilic and systemic symptoms (DRESS) and
multiorgan hypersensitivity
• Idiosyncratic ADRs: hyponatremia, SIADH, cardiac disturbances, osteoporosis
• Dose-related ADRs: diplopia, drowsiness, nausea, sedation
• Monitoring: LFTs, CBC, CMP, CBZ levels
7Oxcarbazepine (OXB)
• MOA: fast sodium channel blocker
• CI: hypersensitivity to OXB or eslicarbazepine
Warnings/precautions:
•Blood dyscrasias
•SJS/TEN - see CBZ
•DRESS and multiorgan hypersensitivity
•Cross hypersensitivity with CBZ
•Hyponatremia (more severe than CBZ)
• Dose-related ADRs: nausea, headache, CNS related
• Monitoring: LFTs, CBC, CMP
8Phenytoin (PHT)
• MOA: sodium channel blocker
• CI: hypersensitivity to PHT or hydantoins, history of PHT-induced hepatotoxicity,
coadministration with delavirdine, IV administration in patients with bradycardia, sinoatrial block, second or third degree AV block, or Adams-Strokes syndrome
• Boxed Warning: cardiovascular events with IV infusion > 50 mg/minute
Warnings/precautions:
•Blood dyscrasias
•SJS/TEN - see CBZ
•DRESS and multiorgan hypersensitivity
•Local toxicity w/ IV use (e.g., purple glove syndrome)
•Hepatic injury
•Exacerbation of porphyria
•Renal or hepatic impairment, hypoalbuminemia, hyperglycemia
•Teratogenic
9Phenobarbital (PB)
• MOA: enhances GABA evoked chloride channels
• CI: hypersensitivity to barbiturates, personal or FH of acute intermittent porphyria, impaired
hepatic function, respiratory disease with obstruction or dyspnea, substance abuse
Warnings/precautions:
•SJS/TEN
•CNS depression
•Paradoxical stimulatory response (children)
•Respiratory depression
•Habit forming (Schedule IV)
• CNS ADRs: somnolence, confusion, cognitive impairment
• Dose-related ADRs: HTN, respiratory depression, coma
• Idiosyncratic: decrease bone mineral density (chronic use)
• Monitoring: CBC, CMP, PB levels (target level = 10-40 mcg/mL)
10Levetiracetam
• MOA: unknown; binds SV2A and inhibits presynaptic calcium channels
• CI: hypersensitivity to levetiracetam; angioedema and anaphylaxis
Warnings/precautions:
•Blood dyscrasias
•SJS/TEN
•CNS depression
•Angioedema and anaphylaxis
•Psychiatric symptoms – psychosis, aggression, anger
• CNS ADRs: drowsiness, ataxia
• Dose-related ADRs: nausea, headache
• Idiosyncratic: cognitive and mood changes, depression, irritability
• Monitoring: CBC, CMP
11Lamotrigine (LMT)
• MOA: blocks sodium and calcium channels, decreased glutamate release
• CI: history of hypersensitivity with other AEDs
Warnings/precautions:
• Blood dyscrasias
• SJS/TEN - typically within 2-8 weeks of initiation
• DRESS
• Phenylketonurics (phenylalanine found in tabs and oral suspension)
• Hemophagocytic lymphohistiocytosis (HLH)
• Aseptic meningitis
• Binding in eye and other melanin-containing tissue
• False (+) for PCP
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18Zonisamide (ZNS)
• MOA: blocks sodium, T-type calcium channels, and increased dopamine
• CI: hypersensitivity to zonisamide, sulfa allergy
Warnings/precautions:
• DRESS
• Metabolic acidosis
• Nephrolithiasis
• Oligohydrosis and hyperthermia (children)
• Renal dysfunction
• Sulfonamide reactions
• Cognitive/neuropsychiatric effects (cognitive dulling, confusion, psychomotor
slowing, depression, psychosis)
19Topiramate (TPM)
• MOA: blocks sodium channels, enhances GABA neurotransmission, inhibits carbonic anhydrase,
blocks AMPA/kinase subtypes of glutamate receptors
Warnings/precautions:
• Metabolic acidosis
• Nephrolithiasis
• Oligohydrosis and hyperthermia
• Cognitive/neuropsychiatric effects (cognitive dulling, confusion, psychomotor slowing, depression, psychosis)
• Acute myopia and secondary angle-closure glaucoma
• Visual field defects
• Hyperammonemia and encephalopathy
• Hypothermia w/ VPA
• Teratogenic
20Gabapentin (GBP)
• MOA: inhibition of alpha-2-delta subunit of voltage-dependent calcium channels
• CI: hypersensitivity to GBP
Warnings/precautions:
• DRESS
• Neuropsychiatric ADRs in pediatric patients (age 3-12 yo)
• Tumorigenic potential
• CNS-related ADRs: dizziness, somnolence, ataxia
• Concentration-related ADRs: drowsiness, sedation
• Idiosyncratic ADRs: peripheral edema, weight gain
• No CYP450 interactions
21Pregabalin
• MOA: inhibition of alpha-2-delta subunit of voltage-dependent calcium channels
• CI: hypersensitivity to pregabalin, angioedema and hypersensitivity reactions
Warnings/precautions:
• SJS/TEN
• Angioedema
• Dizziness/somnolence
• Peripheral edema
• Thrombocytopenia/decreased platelet count
• Prolonger PR interval
• Rhabdomyolysis
• Weight gain
• Tumorigenic potential
• Ophthalmologic effects
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