Adjuncts 2: anticonvulsants, antihistamine, antimicrobials, antiemetics, H2 blockers, diuretics Flashcards
Phenytoin: class
Antiepileptic
Class Ib antiarrythmic
Phenytoin: MoA
Decreases neuronal excitability and inhibits neurotransmission by ↓ sodium and calcium ion transport across neuronal cell membranes.
Phenytoin: PK
Onset = rapid
90% PB
0.7L/kg
E1/2t = 20 hrs + must maintain within tight serum level parameters
Phenytoin: metabolism
Hepatic microsomal enzymes to inactive metabolites.
2% unchanged in urine
Phenytoin: AE
Hypotension, bradycardia, arrhythmias, CV collapse Pain/thrombophlebitis CNS toxicity Hepatotoxicity Stevens Johnson syndrome
Phenytoin: CI
Pregnancy unless benefits outweigh risks. Porphyria Hepatic dysfunction Bradycardia AV block
Phenytoin: dosing
10-25mg/kg @ 50mg/min
Dysrhymias: 50 - 100 mg IV every 15mins to a max of 10 - 15 mg/kg
Diphenhydramine: class
First generation H1 receptor antagonist
Diphenhydramine: MoA
Competes with histamine to antagonizes H1 receptors on target cells in GI tract, blood vessels, and resp tract
Diphenhydramine: PK
Onset: rapid DoA: 4 - 6 hrs E1/2t: 2 - 8 hrs Vd: high 78% PB
Diphenhydramine: metabolism
Hepatic metabolism, first pass effect
Eliminated in urine
Inhibits CYP2D6
Diphenhydramine: AE
Somnolence, nervousness, paradoxical excitement in peds, euphoria, confusion
Delayed emergence if given at end of case!
Hypotension, tachycardia, palpitations
Thickening of bronchial secretions
Urinary retention, epigastric distress, constipation, N/V/D, anorexia, weight gain
Diphenhydramine: CI
Driving or operating heavy machinery
Premature infants, neonates, nursing moms,
Hypersensitivity
Diphenhydramine: dosing
10-50mg IV q6-8 hrs
Max 400mg/day
