Atropine Flashcards
Class
- Parasympatholytic
2. Anticholinergic Agent
Action
- Atropine is a competitive inhibitor of acetylcholine @
muscarinic receptor sites. - The increase of sympathetic activity seen with atropine
administration is due to the drug’s parasympatholytic
effects. - In the setting of symptomatic bradycardias, atropine
decreases vagal effects on the heart resulting in
increased chronotropy & dromotropy (with little or no
inotropic effects). - It is used in cholinergic exposures as a direct antidote
for the poison.
Indications
- Symptomatic Bradycardias
- Pre-intubation in children >1 month of age
- Poisoning w/
- oganophosphates, carbamates, mushrooms, nerve
gas, other cholinergic agents
- oganophosphates, carbamates, mushrooms, nerve
Contraindications
IN ARREST SETTING
none
Contraindications
NON-ARREST
- myasthenia gravis 2. closed-angle glaucoma 3. atrial fibrillation and flutter 4. known hypersensitivity 5. thyrotoxicosis 6. urinary tract obstruction
Precautions
- Atropine may actually worsen 2nd degree Type II & 3rd degree AV blocks. Many experts go as far as to indicate atropine is relatively contraindicated in this setting & transcutaneous pacing is preferred.
- Cardiovascular disease including: CAD & CHF
- COPD
- HTN
- Renal/hepatic disease
- Geriatrics
- Pregnancy I
- Minimum Doses <0.5 mg in adults<0.1 mg in children Smaller doses can cause a paradoxical bradycardia.
Dosage
ADULTS
- Symptomatic Bradycardia: IV: 0.5 mg to 1 mg every 3-5
minutes.Max dose: 0.04 mg/kg (full vagal
blockade). - Poisonings : IV/IM/ETT/IO: 1-2 mg as needed to
decrease cholinergic symptoms.
AUTOINJECTOR (MARK 1 KIT): 2 mg
Dosage
PEDI
Symptomatic Bradycardias: IV/IO: 0.02 mg/kg repeated
every 3-5 minutes as needed. Child: Minimum—0.1
mgMaximum—0.5 mgAdolescent:Minimum—0.1
mgMaximum—1 mgETT: 2-3 times the IV dose diluted in
3-5 ml NS
•Poisonings: IV/IM: 0.05 mg/kg IV every 3-5 minutes as
needed to decrease cholinergic symptoms.
•Pediatric Pre-Intubation: IV/IO: 0.02 mg/kg
Onset
Rapid
Duration
2-6 hrs
Side Effects
•Anticholinergic Effects: Remember the mneumonic:DRY
AS A BONE—Dry mucous membranes, urinary retention,
constipationMAD AS A HATTER—Restlessness,
tachycardia, palpitations, HA, dizzinessRED AS A BEET—
Flushed, hot, & dry skin BLIND AS A BAT—Pupillary dilation
(mydriasis), blurred vision (cycloplegia), photophobia •Tachydysrhythmias, Ventricular Tachycardia/Fibrillation
•Of course…N/V
Interactions
- Anticholinergics increase vagal blockade.
- Potential adverse effects when administered with
digitalis, cholinergics, neostigmine. - Enhanced effects are possible with antihistamines,
procainamide, quinidine, antipsychotics,
antidepressants, benzodiazepines, phenothiazines. - When administered too soon after NaHCO3 (i.e. Without
allowing sufficient fluid to flush the line), a precipitate will
form.
Special Notes
- To recognize cholinergic poisonings remember the
SLUDGE, DUMBELS, and Days of the week mnemonics. 2. Pushing a less than the minimum dose or pushing
atropine too slowly may elicit a paradoxical
bradycardia. - Remember most bradycardias in pediatrics are a result of
hypoxia/hypoxemia rather than a primary cardiac
problem. Ventilation is always preferred over
pharmacological intervention. - Avoid being splashed in the eyes with atropine.•Be
prepared, on physician order, to deliver massive
amounts (10-40mg) in the setting of cholinergic
poisoning.
SLUDGE
Salivation Lacrimation Urination Defecation GI distress Emesis
DUMBELS
muscarinic
Diarrhea Urination Miosis Bradycardia/bronchospasm/bronchorrhea Emesis Lacrimation Salivation/secretion/sweating