• 대한임상독성학회지
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• 제11권1호
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• pp.49-52
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• 2013

Fentanyl, a synthetic, highly selective opioid ${\mu}$-receptor agonist, is 50 to 100 times more potent than morphine. The low molecular weight, high potency, great transdermal permeation rate and lipid solubility of fentanyl make it very suitable for transdermal administration. Durogesic is a novel matrix transdermal system providing continuous systemic delivery of fentanyl. In recently, there are many reports that misused or overused fentanyl transdermal patches result in severe intoxication of fentanyl. We present a case of fentanyl toxicity with misused durogesic transdermal patch and discuss the safe and appropriate application of the patches. In conclusion, fentanyl patches should be used in opioid tolerant patients and prescribed at the lowest possible dose and titrated upward as needed. All patients and their caregivers should be educated safe application of fentanyl patches and advised to avoid exposing the patches application site to direct external heat sources, such as heating pads, or electric blankets, heat lamps, sauna, hot tubs, and others. In addition, concomittant medications that affect fentanyl's metabolism should be avoided.

• The Korean Journal of Pain
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• 제12권1호
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• pp.36-42
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• 1999

Background: The current maximal recommended doses of lidocaine are 7 mg/kg with $5\;{\mu}g/ml$ of epinephrine. But in clinical practice, sometimes more doses of lidocaine are required to produce adequate regional anesthesia. Method: Twenty-two healthy women patients were divided into two groups and pretreated with valium 5 mg p.o., morphine 5 mg i.m., and midazolam 2 mg i.v. before operation. Of these, 7 mg/kg of 2% lidocaine with $5\;{\mu}g/ml$ of epinephrine were given to 11 patients epidurally. Initial 3 ml of epinephrine mixed lidocaine was given as a test dose and remaining doses were given 5 ml/30 sec with 3 min intervals. Radial arterial blood were drawn at 5, 10, 15, 20, 30, 45, 60, 90, 120 min to measure plasma lidocaine concentrations. After confirming all of the peak plasma concentrations of 7 mg/kg lidocaine were absolutely under $5\;{\mu}g/ml$, the other 11 patients were given 10 mg/kg of 2% lidocaine with $5\;{\mu}g/ml$ of epinephrine epidurally and blood samplings were taken according to the same method of 7 mg/kg group. The peak plasma concentration ($C_{max}$), time to reach to $C_{max}$ ($T_{max}$), time to reach to $T_4$, maximal sensory block level, systemic toxicity, and vital sign changes were investigated. Result: $C_{max}$ was significantly higher in 10 mg/kg group ($5.1{\pm}1.3\;{\mu}g/ml$) than 7 mg/kg group($3.3{\pm}0.5\;{\mu}g/ml$), but $T_{max}$ ($10.5{\pm}2.7$ min vs $10.9{\pm}3.1$ min) was not different. Time to reach $T_4$ was significantly shorter in 10 mg/kg group ($9.5{\pm}2.7$ min) than 7 mg/kg group ($12.7{\pm}3.2$ min) but maximal sensory block level ($T_{3.7{\pm}0.7}$ vs $T_{2.7{\pm}1.0}$) was not different. In four patients of 10 mg/kg group, peak plasma concentrations exceeded $5\;{\mu}g/ml$, but no systemic toxicities appeared. No significant vital sign changes were observed. Conclusion: The current maximal recommended doses of lidocaine, merely based on body weight are not always appropriate. Further studies are needed to determine more precise guideline of maximal doses that include various pharmacokinetic components.