Torsades de pointes: Difference between revisions
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==Background== | ==Background== | ||
Drugs that inhibit P450 | Drugs that inhibit P450 | ||
#erythromycin | |||
#biaxin | |||
#ketoconozole | |||
#itraconozole | |||
*certain antihistamines like terfandadine or astemizole, inhibit the delayed rectifier potassium channel | |||
*terfenadine is completely metabolized in liver. Once metabolized, has no cardiac activity | |||
*unmetabolized terfenadine has quinidine- like activity- gives torsades | |||
*if P450 enz inhibited by other drug, then will have increase in concentration of unmetabolized terfanadine. | |||
- | |||
- | |||
==Treatment== | ==Treatment== | ||
#Mg (1-2gm over 1-2 minutes; then, 1-2gm/hr gtt) | |||
#Overdrive pacing (hr = 90-120) | |||
#Isoproterenol (if no pacing, 2-8 mcg/min) | |||
#lidocaine | |||
==Source == | ==Source == | ||
10/07 DONALDSON (adapted from Tintinalli, Lampe) | 10/07 DONALDSON (adapted from Tintinalli, Lampe) | ||
[[Category:Cards]] | [[Category:Cards]] | ||
Revision as of 17:59, 12 March 2011
Background
Drugs that inhibit P450
- erythromycin
- biaxin
- ketoconozole
- itraconozole
- certain antihistamines like terfandadine or astemizole, inhibit the delayed rectifier potassium channel
- terfenadine is completely metabolized in liver. Once metabolized, has no cardiac activity
- unmetabolized terfenadine has quinidine- like activity- gives torsades
- if P450 enz inhibited by other drug, then will have increase in concentration of unmetabolized terfanadine.
Treatment
- Mg (1-2gm over 1-2 minutes; then, 1-2gm/hr gtt)
- Overdrive pacing (hr = 90-120)
- Isoproterenol (if no pacing, 2-8 mcg/min)
- lidocaine
Source
10/07 DONALDSON (adapted from Tintinalli, Lampe)