Bronchodilators Flashcards
‘Albuterol (Proventil, Ventolin)
Class
Sympathomimetic
Bronchodilator
•Mechanism of Action/ Pharmacodynamics
Selective Beta-2 agonist which stimulates adrenergic
receptors of the sympathomimetic nervous system
resulting in smooth muscle relaxation in the Bronchial
Tree (Nebulized form)
Relaxes uterine smooth muscle may be used in preterm labor. Stimulates Na+/K+ pump which reduces serum K+ levels
Albuterol (Proventil, Ventolin)
•Beta-2 Adrenergic Receptors
Bronchial smooth muscle with limited sympathetic innervation yet significant beta-2 adrenergic receptors
Stimulation of these receptors opens Ca++ and K+ channels in smooth muscle
Results in prolonged hyperpolarization and muscle relaxation
Albuterol (Proventil, Ventolin)
•Beta-2 Adrenergic Receptors (continued)
Present on MAST cells, granulocytes and agranulocytes (immune cells)
Activation of these receptors inhibits the chemicals these cells use to initiate inflammation
Thus, albuterol reduces inflammation
•Indications
Treatment of bronchospasm in patients with reversible
obstructive airway disease (COPD/asthma).
Prevention of exercise-induced bronchospasm.
Management of Hyperkalemia
Preterm labor
•Contraindications
Known prior hypersensitivity reactions to Albuterol.
Synergistic with other sympathomimetics
Albuterol (Proventil, Ventolin)
•Albuterol in Hyperkalemia
Albuterol stimulates the Sodium/ Potassium pump which returns extracellular K+ into the cell
Large doses of Albuterol (10-20 mg) can reduce serum potassium .3-.6 mEq/L within 30 min and lasting for 2 hrs (normal K+ 3.5-5.3)
Albuterol (Proventil, Ventolin)
•Adverse Reactions
Often dose-related and include restlessness:
Tremors, Dizziness, Palpitations, Tachycardia (large doses stimulate Beta-1), Nausea, Albuterol (Proventil, Ventolin)
•Drug Interaction
Increases cellular reuptake of K+ from extracellular fluid
May potentiate hypokalemia caused by diuretics
•How Supplied
Solution for aerosolization: 2.5mg/3ml (0.083%)
•Dosage and Administration
Adult: Administer 2.5 mg over 10-15 minutes
MDI: 1-2 inhalations (90-180 mcg). Five minutes between inhalations
Pediatric: Administer solution of 0.01 - 0.03 ml (0.05 - 0.15 mg/kg/ dose diluted in 2 ml of 0.9% Normal Saline.
May repeat every 20 minutes three times
•Duration of Action
Onset in 5-15 minutes with peak effect in 30-minutes - two hours and duration of 3-4 hours
•Special Considerations
Pregnancy Safety: Category C
Antagonized by beta-blockers (e.g., Inderal,Lopressor)
May precipitate angina pectoris and dysrhythmias
Should only be administered by inhalation methodology in pre-hospital management
Repeat doses can cause paradoxical bronchospasm – Do not confuse with the medication not working!
2.08 Respiratory Distress
Adult and Pediatric 2.5-5 mg (initial dose should include IPRATROPIUM BROMIDE 500 mcg, subsequent doses may be +/- IPRATROPIUM) via SVN (may repeat PRN to a max of 4 doses)
Atrovent (Ipratropium Bromide)
•Class:
Bronchodilator
•Mechanism of Action/Pharmacodynamics
Derivative of Atropine
Blocks the action of acetycholine at the
parasympathetic sites (muscarinic) in bronchial smooth muscle
causing bronchodilitation
•Indications:
Used to prevent bronchospasm especially associated with
COPD, and emphysema
Not a fast-acting bronchodilator!
•Contraindications:
Hypersensitivity to atropine or its derivatives
Nut allergy is not a contraindication –Tell your friends!
•Adverse Reactions:
Ipratropium is poorly absorbed from the lung, so
systemic effects are rare.
>10% CNS: Dizziness, Headache, Nervousness
Respiratory: Cough 1-10%
Cardiac: Hypotension, palpitations
•How Supplied:
Nebulizing Ampule: 2.5ml/ vial (0.02%)
•Dosage and Administration:
Adult:
2-3 puffs via metered dose inhaler (MDI) tid-qid; maximum 12 puffs/day.
ALT: 500mcg NEB q 6-8hrs (may mix neb solution with Albuterol if used within 1 hour)
•Dosage and Administration:
Pediatric:
< 12 yo: 1-2 puffs (MDI) tid-qid; max: 8 puffs
ALT: 250mcg NEB q 6-8hrs (may mix neb solution with Albuterol if used within 1 hour)
•Kinetics:
Onset: 1-3 minutes after administration
Peak effects: Within 1.5- 2 hours
Duration of Action: Up to 4-6 hours
T1/2: 2 hrs after inhalation
•Special Considerations
Pregnancy Safety: Category B
When given with Albuterol referred to as Combivent
In cases of bronchospasm, a fast-acting bronchodilator is indicated before a muscarinic inhibitor (Atrovent)
Epinephrine Racemic
(Micronefrin, Vaponefrin)
Class
Sympathomimetic
•Mechanism of Action
Stimulates beta -2 receptors in lungs: bronchodilatation with relaxation of bronchial smooth muscles
Reduces airway resistance
Constricts precapillary arterioles which reduces hydrostatic force and
Laryngeal mucosal edema
Inhibits histamine release
•Indications
Bronchial asthma
Prevention of bronchospasm
Croup: laryngotracheobronchitis
Laryngeal edema
•Contraindications
Hypertension
Underlying cardiovascular disease
Epiglottitis
•Adverse Reactions
Tachycardia
Dysrhythmias
•Drug Interactions
MAOIs may potentiate effects
Beta-blockers may blunt effects
•How Supplied
MDI: 0.16-0.25 mg/ spray
Solution: 7.5, 15, 30 ml in 1%, 2.25% solutions
•Dosage and Administration
•Adult:
MDI: 2-3 inhalations, repeated every 5 minutes PRN
Solution:
Dilute 5 ml (1%) in 5.0 ml NS, administer over 15 min
•Pediatric:
Solution:
Dilute 0.25 ml (0.1%) in 2.5 ml NS (if less than 20kg);
Dilute 0.5 ml in 2.5 ml NS (if 20-40 kg);
Dilute 0.75 ml in 2.5 ml NS (if greater than 40 kg)
Administer by aerosolization
Hydrocortisone Sodium Succinate
(Solu-Cortef)
•Class
Corticosteroid
•Mechanism of Action
Anti-inflammatory and immunosuppressive
with salt-retaining actions
•Indications
Shock due to acute adrenocortical
insufficiency
Bronchoconstriction due to asthma
•Contraindications
None if given as single dose
•Drug Interactions
Incompatible with heparin
•How Supplied
Vials with 100 mg, 250 mg, or 500 mg
•Dosage and Administration
Adrenal Insufficiency/Respiratory (COPD/Asthma)
100mg IV/IO/IM
Pediatric: 0.16-1.0 mg/kg slow IV/IO/IM
•Half Life= 12 hrs
•Special Considerations
Pregnancy Class C
RI OEMS Protocols
•2.04 Allergic Reaction
For patients with severe symptoms:
METHYLPREDNISOLONE 125 mg IV or
HYDROCORTISONE 100 mg IV or
PREDNISONE 60 mg PO
Pediatric: METHYLPREDNISOLONE 2 mg/kg IV (max 60 mg) or
HYDROCORTISONE 2 mg/kg IV (max 100 mg)
RI OEMS Protocols
•2.08 Respiratory Distress
METHYLPREDNISOLONE 125 mg IV or
PREDNISONE 60 mg PO or
DEXAMETHASONE 10-20 mg IV/IM
Pediatric: Consider METHYLPREDNISOLONE 2 mg/kg IV (max 60 mg) or
HYDROCORTISONE 2 mg/kg IV (100 mg max)
Methylprednisolone (Solu-Medrol)
Class
Anti-inflammatory glucocorticoid
•Mechanism of Action
Synthetic steroid that suppresses acute and
chronic inflammation; potentiates vascular smooth
muscle relaxation by beta-adrenergic agonists
•Indications
Acute Spinal cord trauma
Anaphylaxis
Bronchodilator for unresponsive asthma
Acute adrenal insufficiancy
•Contraindications
Premature infants
Systemic fungal infections
Use with caution patients with GI bleeding
•Adverse Reactions
Headache
Hypertension
Sodium and water retention
CHF
Hypokalemia
Alkalosis
Peptic ulcer disease
Nausea
Vomiting
•Drug Interactions
Hypoglycemic responses to insulin and hypoglycemic
agents may be blunted
Potassium-depleting agents may exacerbate
hypokalemic effects
•How Supplied
40, 125, 500 and 1,000 mg vials
•Dosage and Administration
Adult: Acute spinal cord injury: 30 mg / kg IV
over 30 minutes followed by infusion:
5.4 mg/kg/hr. Asthma, COPD: 1-2 mg / kg IV.
Pediatric: Acute spinal cord trauma: 30 mg / kg IV
over 30 minutes; infusion: 5.4 mg / kg / hr
Asthma: 1-2 mg / kg / dose IV
•Duration of Action
Onset of action: 1-2 hours
Peak effects: Variable
Duration of action: 8-24 hours
•Special Considerations
Pregnancy safety: C
Not effective if spinal cord injury greater than 8 hours
Crosses the placenta and may cause fetal harm
RI OEMS Protocols
•2.04 Allergic Reaction
For patients with severe symptoms:
METHYLPREDNISOLONE 125 mg IV or
HYDROCORTISONE 100 mg IV or
PREDNISONE 60 mg PO
Pediatric: METHYLPREDNISOLONE 2 mg/kg IV (max 60 mg) or
HYDROCORTISONE 2 mg/kg IV (max 100 mg)
RI OEMS Protocols
•2.08 Respiratory Distress Asthma/COPD
METHYLPREDNISOLONE 125 mg IV or
PREDNISONE 60 mg PO or
DEXAMETHASONE 10-20 mg IV/IM
Pediatric: Consider METHYLPREDNISOLONE 2 mg/kg IV (max 60mg) or
HYDROCORTISONE 2 mg/kg IV (100 mg max)
RI OEMS Protocols
•2.03 Adrenal Insufficiency
METHYLPREDNISOLONE 125 mg (2 mg/kg, 60 mg max for peds) IV
Magnesium Sulfate (MgSO4)
Class
Electrolyte
•Mechanism of Action
Calcium channel antagonist
Manages seizures in toxemia of pregnancy Induces uterine relaxation
Can cause bronchodilation after beta-agonists and anticholinergics have been used
•Indications
Seizures of eclampsia (Toxemia of pregnancy)
Torsades de Pointes
•Contraindications
Heart blocks
Renal diseases
•Vasodilation
Acts as a Ca++ channel antagonist in smooth muscle thus inactivates calmodulin/kinase reaction Dilates both large and small arteries
•Eclamptic Seizures
The endothelium in the cerebral vasculature is designed to reduce pinocytosis however it is believed that this barrier is disrupted in eclampsia. MgSO4 restores this barrier Antagonizes the NDMA receptor of motor neurons. Glutamate receptors such as NDMA are thought to be involved in seizures when stimulated
Controversy over using in eclampsia due to the possibility of masking the outward signs of convulsions by treating the neuromuscular junction
•Asthma
Acts as a bronchodilator by blocking Ca++ channels on smooth muscle
Magnesium Sulfate (MgSO4)
•Torsades de Points
Torsades is characterized by rapid irregular QRS complexes that twist around the ECG baseline. Can be caused by a long QT interval or hypomagnesemia
Long QT can be caused by a potassium channel antagonist
during phase 3 conduction
•Adverse Reactions
Respiratory and CNS depression
Hypotension
Cardiac arrest
Asystole
Facial flushing
Diaphoresis
Depressed reflexes
Circulatory collapse
•Drug Interactions
May enhance effects of other CNS depressants
Serious changes in overall cardiac function may
occur with cardiac glycosides
Magnesium Sulfate
•Dosage and Administration
Adult:
Seizure activity associated with pregnancy:
1-4 gm IV push over 3 minutes
For Torsades de Pointes or Refractory VF/VT: 1-2 grams IV push over 1-2 minutes
Magnesium Sulfate
•Dosage and Administration (continued)
Asthma:
Adult: 2-4 grams IV/IO over 20 min
Pediatric: 25 mg/kg IV/IO over 2 min
max dose 2 grams
•Duration of Action
Onset: Immediate
Peak effect: variable
Duration: 3-4 hours
RI OEMS Protocols
•2.08 Respiratory Distress
For patients with asthma, consider MAGNESIUM SULFATE 2 gm IV over 10 minutes
Pediatric: Not in Protocol
RI OEMS Protocols
•2.18 Obstetrical Complications
For preterm labor, consider: 4 gm IV over 20 min
RI OEMS Protocols
•3.03 Cardiac Arrest
For polymorphic ventricular tachycardia (Torsades de Pointes) or suspected hypomagnesemia, MAGNESIUM SULFATE 2 gm IV
Pediatric: or polymorphic ventricular tachycardia (Torsades de Pointes), consider MAGNESIUM SULFATE 40 mg/kg IV (may repeat every 5 minutes, 2 gm max)
RI OEMS Protocols
•3.07 Wide Complex Tachycardia
