Pharmacotherapy
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Enoxaparin is a low-molecular-weight heparin that has pharmacokinetic and therapeutic advantages over unfractionated heparin in certain clinical conditions. However, its administration is not without risk. We describe the case of a 70-year-old woman with numerous medical problems who developed severe retroperitoneal bleeding after receiving several therapeutic doses of subcutaneous enoxaparin that inadvertently were not adjusted for her renal function until day 14 of therapy. ⋯ The patient's hemodynamic status improved, and her hemoglobin level stabilized. This case report provides evidence of the clinical effectiveness of factor VIIa use as part of the management of refractory enoxaparin-induced retroperitoneal bleeding. However, further studies are needed to validate the dose-response relationship and further support the clinical utility of factor VIIa in this life-threatening situation.
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Randomized Controlled Trial
The effect of acetaminophen on the international normalized ratio in patients stabilized on warfarin therapy.
To determine whether an interaction exists between acetaminophen and warfarin that alters the international normalized ratio (INR). ⋯ These findings support the existence of a clinically significant interaction between warfarin and daily use of acetaminophen 2-4 g, necessitating close monitoring of patients who receive this drug combination. Whether this interaction occurs when acetaminophen is taken in lower doses or is used sporadically requires further study.
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Review Comparative Study
Iontophoretic drug delivery system: focus on fentanyl.
Fentanyl iontophoretic transdermal system (ITS) is a novel, patient-activated drug delivery device used for the management of acute postoperative pain in the hospital setting. This credit-card-sized device uses an imperceptible current of 170 milliampere to actively deliver a fentanyl hydrochloride 40-microg dose into the vasculature over a 10-minute interval. The unit is programmed to lock out further doses after either 80 doses or 24 hours, whichever is reached first. ⋯ Although adverse effects were congruent with those expected from pure-agonist opioids, subjects assigned to the ITS group did experience a higher rate of mild, clinically nonsignificant erythema at the system placement site. Judicious monitoring for opioid-induced respiratory depression is recommended for fentanyl ITS, although this adverse effect has not been observed in clinical trials. Fentanyl ITS may provide another useful alternative in the management of acute postoperative pain.
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Case Reports
Severe lactic acidosis associated with linezolid use in a patient with the mitochondrial DNA A2706G polymorphism.
Linezolid, an oxazolidinone antimicrobial, exerts its effect by binding to bacterial 23S ribosomal RNA, preventing the formation of the initiation complex. Its use is associated with reversible hyperlactatemia and lactic acidosis, and inhibition of mitochondrial protein synthesis may be the mechanism underlying this adverse effect. ⋯ This patient was found to have the mitochondrial DNA polymorphism A2706G, a variation previously suggested to predispose individuals to linezolid-associated lactic acidosis. In the future, increased understanding of the mitochondrial genome and its associated polymorphisms may allow us to identify patients at risk for adverse effects that were previously classified as idiosyncratic.
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To investigate the dosing, tolerability, and outcomes associated with the use of concomitant beta-blockers and inotropic therapy in patients with refractory heart failure during the first 6 months of their therapy. ⋯ Inotrope-dependent patients with refractory end-stage heart failure tolerated continuous intravenous milrinone plus beta-blockers in addition to diuretics and vasodilators for the 6-month observation period. Beta-blocker dosages were titrated, and three patients achieved the target beta-blocker dosage established for stage A-C heart failure. Additional studies are needed to determine the optimal selection and dosing of drug combinations in this population.