Second Generation Anticonvulsants DRUG Indications Mechanism of Action Adverse Effects Interactions Lamotrigine ↓ 1st line Tx for long-term therapy ↓ 1st line of focal seizures for management of tonic-clonic seizures Θ of Nat voltage gated channel →↓ glutamate release * Rash * Exfoliative dermatitis * Steven Johnson Syndrome (Slow titration is necessary to Θ skin's mucous membrane rxn) * Hemophagocytic lymphohistocytosis * Rarely hepatotoxic or nephrotoxic * Blurry vision * GIT upset * Sedation * Dizziness * DRESS syndrome Coadministration of carbamazepine, phenobarbital, phenytoin →↑ clearance Tiagabine Focal seizures +l- consciousness (adjunctive therapy) Θ GABA reuptake →↑ GABA * Dizziness * GIT upset * Insomnia * Drowsiness * Weight changes Coadministration of carbamazepine, phenobarbital, phenytoin →↑ clearance Levetiracetam * 1st line Tx for long term therapy of focal seizures * Generalised seizures * Not fully understood * Θ SV2A-R → GABA &lor glut. release modulation & Θ of Ca2+ voltage gated channels * lethargy * fatigue * nausea * headache * sedation * dizziness * psychiatric symptoms (e.g. personality changes) Nothing significant Pregabalin (not FDA approval) (Gabapentinoids) * Drug combo for long-term tx of focal seizures * Neuropathic pain * Neuralgia after herpes infection * GAD * Θ of presynaptic P/Q type Ca2+ channels via action on $\alpha$2$\delta$ subunit →↓ Ca2+ intra-cellr-lwr Flow →↓ glutamate releas * doesn't bind to GABA-R despite being a GABA analog * Somnolence * Nausea * Ataxia * Dizziness * Weight gain Nothing significant Gabapentin (Gabapentinoids) * 2nd line Tx for focal seizures * Postherpetic neuralgia * peripheral polyneuropathy Same as previous * Dry mouth * somnolence * nausea * ataxia * dizziness * weight gain Morphine ↑ CI of gabapentin Vigabatrin * Refractory focal seizures (adjunctive therapy) * Monotherapy for infantile spasms (West Syndrome) Θ GABA transaminase irreversibly →↑ GABA irreversible vision loss ↓ happens in upto 50% of pts only use in other pts if other anticonvulsants are ineffective ↓ Sr levels of phenytoin Topiramate * Focal & generalised tonic-clonic epileptic seizures * Migraine prophylaxis * Idiopathic intracranial HTN Θ of voltage-gated Na+ channels * ↑ GABA * Angle closure glaucoma * Weight loss * K stones * Cognitive dysfunction * Sedation * Dizziness * Mood disturbance * Depression * Paresthesia ↓ efficacy of oral contraceptives