Please enable JavaScript.
Coggle requires JavaScript to display documents.
Anticonvulsants - Coggle Diagram
Anticonvulsants
Lamotrigine
-
Indication: monotherapy or add-on therapy for focal, generalised, JME, Lennox-Gastaut
Drug interaction: can be victim of drug interactions, but is not inhibitor or inducer
MOA: exact mechanism unknown, stabilises presynaptic neuronal membranes by acting on voltage sensitive Na channels & modulating presynaptic transmitter release of excitatory neurotransmitters (e.g. glutamate)
Adverse effects: benign rash, hypersensitivity, SJS/TEN, DRESS, ataxia, diplopia
Metabolism: UDP-glucuronosyltransferase (inhibited by valproate, induced by phenytoin)
Caution: slow dose escalation over weeks, risk of life threatening rash if recommended titrations exceeded
Phenytoin
-
Adverse effects: systemic hypersensitivity reaction, gum hypertrophy, folic acid depletion, decreased bone density, hirsutism & acne
-
Drug interactions: strong inducer of drug metabolising enzymes (CYP & UGT-glucuronidation) & transporters
-
Toxicity: CNS - somnolence, ataxia, confusion nystagmus (cerebellar Sx), CVS - ventricular arrhythmia
-
Carbamazepine
-
Adverse effects: drowsiness, vertigo, ataxia, diplopia, blurred vision, aplastic anaemia, agranulocytosis, systemic hypersensitivity reaction
MOA: prolongs inactivation of voltage sensitive Na channels, potentiates postsynaptic actions of GABA
Drug interactions: strong inducer of drug metabolising enzymes & transporters, oral contraceptive concentrations reduced
-
Valproate
MOA: prolongs inactivation of voltage gates Na channels, increases GABA synthesis
Adverse effects: alopecia, ataxia, sedation, bone marrow suppresion, idiosyncratic hepatotoxicity, polycystic ovarian syndrome, menstrual irregularities
-
-
Indications: focal, generalised tonic-clonic and absence seizures
-
Phenobarbital
-
Adverse effects: hyperactivity in children, agitation & confusion in elderly, systemic hypersensitivity reaction, sedation (decreases over time with tolerance)
-
Drug interactions: strong inducer of drug metabolising enzymes (CYP450) & transporters - affects oral contraceptives
-
-
Status epilepticus
Immediate: IV benzodiazepine (e.g. lorazepam, diazepam, clonazepam)
If no IV access: buccal (lorazepam & midazalom only), IM (lorazepam & clonazepam only), PR diazepam
Prevent further seizures: IV infusion phenytoin loading dose followed by maintenance doses
Children: IV phenobarbitone infusion preferred
If still not controlled
-
Remember that barbiturates (phenobarbitone & thiopentone) induce the metabolism of phenytoin - concentrations should be monitored
-
-
-
-
-