Revisiting Pharmacological Principles DANIEL BECKER, DDS MIAMI VALLEY HOSPITAL DAYTON, OH DEBECKER@PREMIERHEALTH.COM
Drug Kits Expiration Dates “Many solid drugs stored under reasonable Med Lett Drugs Ther. 2015 Dec Comfort Level of Practitioner ? conditions in their original unopened 7;57(1483):164-5 EMS Response Times ? containers retain 90% of their potency for at Dental Board Requirements ? least 5 years after the expiration date on the label, and sometimes much longer.” Preparations ? • Amps “Solutions and suspensions are generally • Vials less stable but in one report, four outdated samples of atropine solution (three up to 12 • Prefilled Syringes years past expiration were all found to Routes ? contain significant amounts of the drug. “One study found that EpiPens • IV Drugs in solution that have become cloudy 3-36 months past their • IM or discolored or show signs of precipitation, expiration dates contained 84.2- • SC particularly injectables, should not be used.” 101.5% of the labeled dose.” • SLI Sedation Reversal Algorithm Emergency Kit Triple Airway: Head Tilt / Chin Lift / Jaw Thrust Assess ! Remove Cases Sedation Reversal Cardiac Arrest Bradycardia/Hypotension Breathing ? YES NO Algorithm Allergy / Asthma Chest Pain Airways, Suction, Hypertension SpO 2 < 95 BVM Ventilation Extra Syringes, SpO 2 ≥ 95 Stethoscope. Stroke AND Reversal ! #1 ↑ Supplemental O 2 Chest Rise ? Support Item# 10048200 12-Case • Cannula 4-6 L/min SpO 2 ≥ 95 ? Photo Storage Carrier Consider • NRB 6-10 L/min If No, Add Adjunct: Reversal #2 Assist Ventilation $32.99 / ($46.05 Tax/Shipping) #1 Oral Airway • BVM 10-15 L/min Consider Reversal #2 Supraglottic Airway The Container Store (800 733 3532) Opioid Reversal BZ Reversal www. Containerstore.com Naloxone 0.4 mg/ 1 mL x 2 (SLI, IV) Flumazenil 0.2 mg / 2 mL x 5 (SLI, IV) Duration for CNS Brain Reversal Agents Effects Distribute Muscle, Fat Kidney, Liver Act as receptor antagonists. Determined by time at site, not Distribute & When control of airway and ventilation are difficult, or by time in body Redistribute unconsciousness is not intended. Distribution time (T 1/2α ), not Elimination time (T 1/2β ) Generally eliminate opioid first BUT must consider BZ or Eliminate How many T 1/2 Required? (1-4?) Opioid dependence ! Opioids Naloxone Fentanyl Alfentanil Remifentanil Flumazenil Naloxone Distribution T 1/2α (min) 5-8 m 9.2-19 m 9.5-17 m 2.0-3.7 m Formulation 0.1 mg/mL 0.4 mg/mL Elimination T 1/2β (hr) 0.5-1.5 h 3.1-6.6 h 1.4-1.5 h 0.17-0.33 h Conventional Dose 0.2 mg (2 mL) 0.4 mg (1 mL) Sedatives Flumazenil Midazolam Diazepam Distribution T 1/2α (min) 4-11 m 7-15 m 10-15 m Data from Incremental Doses 0.1 mg (1 mL) 0.2 mg (0.5 mL) Miller’s, Barash, Elimination T 1/2β (hr) 0.4-1.4 h 1.7-2.6 h 20-50 h et al. Becker DE. Emergency Drugs 1
Flumazenil Naloxone Rapid reversal may lead to nausea/vomiting. Renarcotization not an issue with conventional doses Resedation following flumazenil is overstated of fentanyl or remifentanil. and is dose-dependent. Concerns regarding pulmonary edema only when no local anesthesia present. “Resedation is least likely in cases where flumazenil is administered to reverse a low dose of a short-acting “Excessive dosage may result in significant reversal of benzodiazepine (less than 10 mg midazolam). It is most analgesia and increase in blood pressure. Similarly, too likely in cases where a large single or cumulative dose of a rapid reversal may induce nausea, vomiting, sweating or benzodiazepine has been given in the course of a long circulatory stress.” (Facts & Comparisons 2016) procedure along with neuromuscular blocking agents and multiple anesthetic agents.” (Facts & Comparisons 2016) Bronchodilators Anticholinergics Bronchospasm may be attributed to asthma, COPD, anaphylaxis Act as muscarinic (M) receptor or aspiration. antagonists, blocking parasympathetic influences. Selective Beta-2 agonists ideal but epinephrine (per anaphylaxis) also acceptable. Albuterol: Terbutaline: (?) Full expiration Presynaptic & Postsynaptic Muscarinic Receptors SC: 0.25 mg repeat Activate with full 15-30min Subtype Location Subtype Location inspiration If IV (tocolysis): M 1 Presynaptic M 3 Glands Hold breath 6-10 sec 5 mcg/min x 5 M 2 Heart M 4,5 CNS Repeat 2-4 times Atropine for Bradycardias Anticholinergic Drugs Acts by blocking vagal influence on CNS Heart Secretions heart Drug Adult Dose (IV) Duration (M 4,5 ) (M 2 ) (M 3 ) Effective: Atropine 0.5 mg * 15-30min + +++ ++ • Sinus bradycardia • 1 st degree AV block Scopolamine 0.3 mg 30-60min +++ 0,+ +++ • 2 nd degree Mobitz I AV block Glycopyrrolate 0.2 mg 2-4hr 0 ++ +++ Atropine is also available in concentrations of 0.3 and 0.4mg/mL but doses lower than 0.5 mg may be associated with paradoxical Ineffective for higher degree blocks: Mobitz II and 3 rd degree vagotonic effects that result in further slowing of heart rate ! Brown JH, Laiken N. Muscarinic Receptor Agonists and Antagonists. In: Goodman and Gilman's The Pharmacological Basis of Therapeutics. 12th edition 2011. Glick DB. The Autonomic Nervous System. In: Miller's Anesthesia. 7th edition 2009. Becker DE. Emergency Drugs 2
Vasopressors act as adrenergic receptor Mean Arterial Pressure Ephedrine ~ Phenylephrine ~ agonists, mimicking sympathetic influences. Systolic Blood Pressure Diastolic Blood Pressure C Heart Rate [ Cardiac Output = HR x SV ] [ Arterial Resistance ] HR HR ▪ Sympathetic (Beta-1) ↑ SBP B SBP ▪ Parasympathetic (Cholinergic) ↓ 1. Preload (+) Epinephrine Ephedrine Phenylephrine Pulmonary Circuit DBP ▪ Venous Return A α, β 1 , β 2 DBP ▪ Venoconstriction ↑ Action α, β 1 , β 2 α and Indirect Stroke Volume ▪ Venodilation ↓ 3 2 Duration 3-5 min 1-2 hr 15 min 1 2. Contractility (+) Cardiac Output (L/Min) Formulation 1 mg/mL 50 mg/mL 10 mg/mL ▪ Sympathetic (Beta-1) A DBP - Beta 2 vs Alpha 10 mcg 3. Afterload (DBP) SBP - Beta 1 vs Alpha (veins B 10 mg 0.1 mg ▪ Arterial Constriction ↑ (alpha ) increments or Dosage (IV) preload + reflex response to afterload) increments increments ▪ Arterial dilation ↓ (Beta-2) 2-10 mcg/min C HR – Beta 1 vs Reflex to MAP ▪ Negative influence Epinephrine IM Epinephrine IV Drug 1:1000 1:10,000 Administration 1 Gm / 1000 mL 1 Gm / 10,000 mL 1000 mg / 1000 mL 1000 mg / 10,000 mL Ephedrine Phenylephrine 1 mg / mL 0.1 mg / mL This concentration ONLY Formulation 50 mg/mL 10 mg/mL (1000 mcg / mL) (100 mcg / mL) for Cardiac Arrest ! 0.3 mg (0.3mL) IM for 1 mg (10 mL) IV for Dosage 10 mg increments 0.1 mg increments anaphylaxis Cardiac Arrest • 0.1 mL = 1 mg For Hypotension or severe anaphylaxis MUST dilute ! • 0.1 mL = 5 mg Use Tuberculin • Dilute to 1 mL (10 mcg increments or 2-10mcg/min infusion) Syringe: • 0.1mL = 0.1 mg • Use tuberculin syringe • 1�mg (1�mL) in 500 or 250�mL of normal saline or D5W • Draw 0.1 mL = 100 mcg • Provides 2�or 4 mcg/mL • Dilute to 1 mL respectively (1-2 mL/minute) • 0.1 mL = 10 mcg/min Lieberman P, et al . J Allergy Clin Immunol 2010; 126(3):477-80. e1-42. Marx JA, et al. Rosen's Emergency Medicine 8 th Ed 2014 Antihypertensives Antihypertensives * * * Nitroglycerin (1 tab Q5min) URGENCY if No Symptoms EMERGENCY if Symptoms • Rarely Require Treatment • Headache, Paresthesia, • Venodilation reduces preload Chest Pain • Address Possible Causes for Sudden Elevation • EMS Transport Esmolol (20-30mg Q2-3min) • Beta-1 Blocker reduces HR and contractility “The most sensible approach to the patient in the ED found to have very high blood pressure, without evidence of acute end organ Labetalol (10-20mg Q3-5min) damage, is referral for outpatient management of serious disease that needs to be treated; not urgently, but for life. Focusing on the • Beta-1, Beta-2 and Alpha Blocker height of the column of mercury in the sphygmomanometer confers • Reduces contractility, venodilation reduces preload no demonstrable benefit on the patient and risks doing harm.” and arterial dilation reduces arterial resistance Caution: Beta -2 blockade may produce Gallagher EJ. Ann Emerg Med 2003;41:530-31 bronchospasm & epinephrine interaction Becker DE. Emergency Drugs 3
Recommend
More recommend
