Clinician's Pocket Drug Reference 2008

170 Phenylephrine, systemicPhenylephrine, systemic (Neo-Synephrine) WARNING: Prescribersshould be aware of full prescribing info before use Uses: *Vascular failurein shock, allergy, or drug-induced ↓ BP* Action: α-adrenergic agonist Dose:Adults. Mild–moderate ↓ BP: 2–5 mg IM or SQ ↑ BP for 2 h; 0.1–0.5 mg IV elevatesBP for 15 min. Severe ↓ BP/shock: Cont inf at 100–180 mcg/min; after BPstable, maint 40–60 mcg/min Peds. ↓ BP: 5–20 mcg/kg/dose IV q10–15 min or0.1–0.5 mcg/kg/min IV inf, titrate to effect. Caution: [C, +/–] HTN, acute pancreatitis,hepatitis, coronary Dz, NAG, hyperthyroidism Contra: Bradycardia, arrhythmiasDisp: Inj 10 mg/mL SE: Arrhythmias, HTN, peripheral vasoconstriction↑ w/ oxytocin, MAOIs, & TCAs; HA, weakness, necrosis, ↓ renal perfusionNotes: Restore blood volume if loss has occurred; use large veins to avoid extrav;phentolamine 10 mg in 10–15 mL of NS for local inj to Rx extravPhenytoin (Dilantin) Uses: *Sz disorders* Action: ↓ Sz spread in themotor cortex Dose: Load: Adults & Peds. 15–20 mg/kg IV, 25 mg/min max or POin 400-mg doses at 4-h intervals. Maint: Adults. Initial, 200 mg PO or IV bid or300 mg hs; then follow levels. Peds. 4–7 mg/kg/24h PO or IV ÷ daily–bid; avoidPO susp (erratic absorption) Caution: [D, +] Contra: Heart block, sinus bradycardiaDisp: Dilatin Infatab chew 50 mg; Dilantin/Phenytek capsules 100 mg; capsules,ER 30, 100, 200, 300 mg; susp 125 mg/5 mL; inj 50 mg/mL SE:Nystagmus/ataxia early signs of tox; gum hyperplasia w/ long-term use. IV: ↓ BP,bradycardia, arrhythmias, phlebitis; peripheral neuropathy, rash, blood dyscrasias,Stevens–Johnson synd Notes: Levels: Trough: just before next dose; Therapeutic:Peak 10–20 mcg/mL; Toxic > 20 mcg/mL; Phenytoin albumin bound, levels =bound & free phenytoin; w/ ↓ albumin & azotemia, low levels may be therapeutic(nl free levels); do not change dosage at intervals < 7–10 d, hold tube feeds 1 hr beforeand after dose if using oral suspPhysostigmine (Antilirium) Uses: *Antidote for TCA, atropine, &scopolamine OD; glaucoma* Action: Reversible cholinesterase inhibitor Dose:Adults. 0.5–2 mg IV or IM q 20 min. Peds. 0.01–0.03 mg/kg/dose IV q15–30 minup to 2 mg total if needed Caution: [C, ?] Contra: GI/GU obst, CV Dz Disp: Inj1 mg/mL SE: Rapid IV admin associated w/Szs; cholinergic side effects; sweating,salivation, lacrimation, GI upset, asystole, changes in HR Notes: Excessive readministrationcan result in cholinergic crisis; crisis reversed w/ atropinePhytonadione [Vitamin K] (AquaMEPHYTON, others) Uses:*Coagulation disorders due to faulty formation of factors II, VII, IX, X*; hyperalimentationAction: Cofactor for production of factors II, VII, IX, & X Dose: Adults& Children. Anticoagulant-induced prothrombin deficiency: 1–10 mg PO or IVslowly. Hyperalimentation: 10 mg IM or IV qwk. Infants. 0.5–1 mg/dose IM, SQ,or PO Caution: [C, +] Contra: Allergy Disp: Tabs 5 mg; inj 2, 10 mg/mL SE:Anaphylaxis from IV dosage; give IV slowly; GI upset (PO), inj site Rxns Notes:W/ parenteral Rx, 1st change in PT usually seen in 12–24 h; use makes recoumadinizationmore difficult