Digoxin toxicity: Difference between revisions
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==Background== | == Background == | ||
*Positive inotropic effect | |||
** Inhibits Na-K pump -> increased intracellular Na -> increased intracellular Ca | |||
AV block | |||
RISK FACTORS | RISK FACTORS | ||
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-CCBs | -CCBs | ||
== Diagnosis == | |||
Toxic Side Effects | Toxic Side Effects | ||
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-asscociated with worse outcomes in acute OD | -asscociated with worse outcomes in acute OD | ||
== Treatment == | |||
-Gastric empytying if SOON after ingestion | -Gastric empytying if SOON after ingestion | ||
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-Forced diuresis, hemodialysis, hemoperfusion ineffective in removing dig | -Forced diuresis, hemodialysis, hemoperfusion ineffective in removing dig | ||
Indications for Rx of rhythm disturbances | Indications for Rx of rhythm disturbances | ||
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-frequent/complex ventricular ectopy | -frequent/complex ventricular ectopy | ||
Bradycardia | Bradycardia | ||
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-if bradycardic, can worsen with K* | -if bradycardic, can worsen with K* | ||
Tachyarrhythmias, increased automaticity | Tachyarrhythmias, increased automaticity | ||
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-Cardioversion | -Cardioversion | ||
Digibind | Digibind | ||
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-Ab-dig complex excreted in the urine | -Ab-dig complex excreted in the urine | ||
Indications | Indications | ||
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-co-ingestion of cardiotoxic drugs: CCBs, beta-blockers, or TCAs | -co-ingestion of cardiotoxic drugs: CCBs, beta-blockers, or TCAs | ||
Empiric Dosages | Empiric Dosages | ||
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-Cariac arrest = 20 vials undiluted by IV bolus | -Cariac arrest = 20 vials undiluted by IV bolus | ||
Calculated Dosages: see package insert | Calculated Dosages: see package insert | ||
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-(dig level x wt in kg)/ 100 = # of vials | -(dig level x wt in kg)/ 100 = # of vials | ||
Kinetics | Kinetics | ||
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-Full effect: 90mins | -Full effect: 90mins | ||
**Note** digitalis level unreliable after digibind administration, must follow patient clinically | **Note** digitalis level unreliable after digibind administration, must follow patient clinically | ||
== Complications == | |||
-potential allergic reactions | -potential allergic reactions | ||
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-dig levels not usable | -dig levels not usable | ||
== Source == | |||
Adapted from Rosens 7th Edition | Adapted from Rosens 7th Edition | ||
<br/>[[Category:Tox]] <br/><br/> | |||
[[Category:Tox]] | |||
Revision as of 05:32, 18 March 2011
Background
- Positive inotropic effect
- Inhibits Na-K pump -> increased intracellular Na -> increased intracellular Ca
AV block
RISK FACTORS
Increased sensitivity to dig
-electrolyte disturbances (eg hypoK)
-hypoxia
-cardiac ischemia
-Increased Dig levels
-renal insufficiency
-CCBs
Diagnosis
Toxic Side Effects
GI
-N/V
Neurologic
-Classic: yellow hallows around vision
Cardiac
Vagal
Rhythm disturbances
-depressed condxn/impulse formation
-enhanced automaticity
-can see almost any rhythm except afib with RVR; hence there is no diagnostic arrhythmia
-serum dig levels often not helpful*
HyperK
-asscociated with worse outcomes in acute OD
Treatment
-Gastric empytying if SOON after ingestion
Charcoal (need 10x the ingested dose); usually 25-100g PO
Toxic effects may be delayed SEVERAL hours (serum/myocardial levels equilibrate in 6-8h)
Temporary discontinuation of dig often sufficient
Tx of hyperkalemia
-bicarb, glucose/insulin may be ineffective
-calcium contraindicated (usually)
-dig-Ab
-Forced diuresis, hemodialysis, hemoperfusion ineffective in removing dig
Indications for Rx of rhythm disturbances
-hemodynamic compromise caused by bradycardia or tachycardia
-frequent/complex ventricular ectopy
Bradycardia
-Atropine
-Electrical pacing
-K contraindicated UNLESS severe hypok*
-if tachycardic, give K*
-if bradycardic, can worsen with K*
Tachyarrhythmias, increased automaticity
-K
-Mag
-Lidocaine
-Phenytoin
-Cardioversion
Digibind
-Ab bind to dig, remove drug from serum and myocardium
-Ab-dig complex excreted in the urine
Indications
-severe rhythm disturbances refractory to conventional therapy
-hyperkalemia >5 after ACUTE OD
-very large ingested dose or very high serum dig level (eg4-10)
-co-ingestion of cardiotoxic drugs: CCBs, beta-blockers, or TCAs
Empiric Dosages
-Acute Ingestion: give 10-20 vials over 30 minutes through 0.22 micron filter
-Chronic toxicity and unkown level: 4-6 vials (1/2 vial in child)
-Cariac arrest = 20 vials undiluted by IV bolus
Calculated Dosages: see package insert
-1 vial (40mg) binds 0.6mg dig
-Dose (vials) = body load (mg)/0.6 (mg/vial)
-dig body load estimated from ingested dose or serum level
-(dig level x wt in kg)/ 100 = # of vials
Kinetics
-Onset: 20mins
-Full effect: 90mins
- Note** digitalis level unreliable after digibind administration, must follow patient clinically
Complications
-potential allergic reactions
-w/d of dig effect:
-CHF
-hypoK
-dig levels not usable
Source
Adapted from Rosens 7th Edition