Part 2 Flashcards
Pregabalin (PGB)
-Lyrica
C-5 controlled substance
-Available as capsule and soln
Used for:
- adjunct therapy for adult patients with partial onset seizures
- Neuropathic pain
-Structurally related to GABA, but DO NOT bind to GABA or benzodiazepine receptors
MOA:
- Binds to alpha-2 delta subunit of voltage-dependent Ca2+ channels within the CNS and INHIBITS excitatory neurotransmitter release including: - Glutamate - NE - Seratonin - Dopamine - Substance P - Calcitonin gene related peptide
**100% RENALLY excreted
- *CrCl < 60 ml/min
- decrease the dose or extend the dosing interval (similar to gabapentin)
**Pregnancy C
Pregabalin (PGB)
-Lyrica
Side effects, monitor, DDIs
Side effects:
-Sedation
-Dizziness
-Edema
-Weight GAIN
-(Rarely) myopathy and rhabdomyolosis)
(dry mouth, blurred vision, difficulty concentrating)
Monitor:
- Scr - Edema - Weight GAIN
DDIs:
- Minimal - OK to use with oral contraceptives - Caution with "glitazones" due to risk of additive edema (caution in CHF)
Pregabalin (PGB)
-Lyrica
Patient education
- Drowsiness/dizziness
- If blurred vision, excessive swelling or muscle aches occur, contact MD
Topiramate
-Topamax
Used for:
- Partial seizures
- Primary generalized tonic-clonic seizures (as adjunct)
- Lennox Gastuat (as adjunct)
- Conversion to primary therapy from older drugs
- Migraine prophylaxis
MOA:
- Blocks Na+ channels that enhances GABA - Glutamate blocker - Weak carbonic anhydrase inhibitor
- *70% is RENALLY eliminated
- *CrCl < 70 ml/min
- Decrease the dose by 50%
Topiramate products
Topiramate
- Topamax - Topamax sprinkle - Topiragen
Topiramate ER
- Qudexy XR - Trokendi XR
**Available as capsules, ER capsules, tablets
Topiramate
-Topamax
Contraindications, side effects, monitor, drug interactions
Contraindications:
- Trokendi XR - Recent alcohol use (within 6 hours prior to and 6 hours after dose) - Metabolic acidosis + taking metformin
Side effects:
- CNS/cognitive (i.e hyper-ammonia) - Anorexia (weight LOSS) - Parasthesia -Less common: -Nephrolithiasis (kidney stones) -Angle closure glaucoma (myopia, non-anion gap acidosis, oligohydrosis (reduced perspiration/hyperthermia, hyperammonia (both alone and in combination with VALPROIC ACID)
Monitor:
- Scr - Serum bicarb
DDIs
- Reduced efficacy of estrogenic oral contraceptives - Increased risk of nephrolithiasis with: - ketogenic diet - acetazolamide - zonisamide
Topiramate
-Topamax
Patient education
- Drowsiness
- Numbness/tingling
- Keep adequate fluid intake to AVOID kidney stones
- If forgetfulness, blurred vision, eye pain occurs, consult MD
- Decreased efficacy of birth control, especially with doses >200 mg daily; use back up
Lamotrigine
-Lamictal
Broad spectrum (similar to Valproic acid)
Used for:
- Partial seizures
- Primary and secondary generalized tonic-clonic seizures
- Lennox Gastaut
- Bipolar
MOA:
- Blocks Na+ channels - Inhibits glutamate release
- *NOT a CYP450 substrate
- *Hepatic UGT metabolism
- When added to a UGT enzyme INDUCER (CBZ, PHT, PB, PRIM, Rifampin, lopinavir/ritonavir, estrogen-OCs):
- t1/2 is REDUCED from 25 to 14 hours- When added to a UGT INHIBITOR (VPA) - t1/2 is INCREASED to 60 hours
**Pregnancy C
Lamotrigine Products
Available as tablet, chewable, ODT
- Lamotrigine
- Lamictal
- Lamictal starter**
- Provide the recommended dose/titration schedule for the first 5 weeks; titration schedule is based on concomitant medications - Lamictal ODT**
- Provide the recommended dose/titration schedule for the first 5 weeks; titration schedule is based on concomitant medications - Lamictal XR
Lamotrigine
-Lamictal
Dosing
Starting dose:
-50 - 250 mg BID
Week 1 and 2:
-25 mg daily
Week 3 and 4:
-50 mg daily
Week 5 and on:
-Can increase by 50 mg daily every 1-2 weeks
Maintainence dose:
-300 - 400 mg daily (split BID)
For patients on VPA: (cut dose in half)
-Week 1 and 2: 25 mg QOD
For patients on hepatic inducers (or smokers, you double the dose)
-Week 1 and 2: 50 mg daily
Lamotrigine
-Lamictal
Black box warning, tolerability/side effects, monitoring
Black box warning:
- Serious rash - SJS/TEN - Risk factors: 1) young age (< 16 years) 2) co-medication with VPA 3) Rapid titration 4) High starting dose
Tolerability/side effects:
- Well tolerated - Low sedation and cognitive side effects - NO weight GAIN - No osteopenia - Low teratogenicity (Pregnancy C)
Monitoring:
- LFTs - Signs/symptoms of rash
Lamotrigine
-Lamictal
Patient education
- Drowsiness
- Dizziness
- Doses will be increased gradually; make take several weeks to reach maintenance dose
- Comes in child-resistant packaging
- Starter-kit packaging:
- Orange: for those NOT taking interacting medications- Blue: for those taking VPA - Green: for those taking an INDUCER
- *If rash occurs, contact MD immediately
- *Folic acid
-Importance of compliance
Levetiracetam
- Keppra
- Keppra XR
- Spritam
Used for:
- Partial seizures
- Secondary general tonic-clonic seizures
MOA:
- Exact MOA is unknown - May inhibit voltage-gated N-type Ca2+ channels and facilitate GABA-ergic inhibitory transmission through its displacement of negative modulators
- *IV and oral
- *100% oral bioavailability
- *70% RENALLY excreted
- *CrCl (less than or equal to) < 80 ml/min
- Requires dose REDUCTION - WARNING
- behavioral abnormalities and psychotic symptoms
- SJS/TEN
Notable side effects:
- Sedation - Dizziness - Weakness - Coordination difficulties - Dose related behavior changes
NO significant DDIs:
- No effect on other AED levels - No effect on oral contraceptives
Levetiracetam
- Keppra
- Keppra XR
- Spritam
Patient education
- Drowsiness
- Inform MD of any change in behavior or mood
-Spritam uses ZipDose technology with 3D printing to produce a porous tablet formulation that rapidly dissolves with a sip of liquid
Felbamate
-Felbatol
**tablet, suspension
Broad spectrum (similar to valproic acid and lamotrigine)
Used for:
- Partial seizures
- Primary and secondary generalized tonic-clonic seizures
- Reserved for REFRACTORY cases*
MOA:
- NMDA blocker - GABA enhancer
Black box warning:
- Aplastic anemia - Risk factors: 1) Hx of AED allergy or toxicity 2) Immune disorder 3) Previous cytopenia 4) Caucasian 5) Female 6) Adult - Hepatotoxicity that can be FATAL
Side effects:
- Insomnia - Anorexia (weight loss -- similar to Topiramate) - Headache - N/V - Gingival hypertrophy (similar to phenytoin)
Monitor:
- CBC twice monthly - LFT weekly
DDIs:
- P450 inducer and inhibitor - decreases levels of oral contraceptives