Endophthalmitis associated with intravenous drug use

Infectious complications related to i.v. drug use represent an important source of morbidity and mortality among this population. We report an informative case of endogenous endophthalmitis related to injection of cocaine mixed with lemon juice. Clinicians should remember that any visual change among patients using injection drugs warrants aggressive workup, including empiric antifungal therapy. Once the disease is identified, early vitrectomy should be considered.     

Edematous pancreatitis associated with intravenous pentamidine

A 37-year-old black man with presumed Pneumocystis carinii pneumonia who was treated with systemic IV pentamidine had fatal pancreatitis and massive hepatomegaly. Fatal pancreatitis can occur with no hemorrhagic changes seen at autopsy. Awareness of the relationship between pentamidine and pancreatitis should be emphasized. With current clinical trials testing other routes of administration, fatal complications associated with IV pentamidine therapy will be minimized.     

Deaths associated with inappropriate intravenous colchicine administration

Intravenous (IV) colchicine is occasionally prescribed for the treatment of acute gouty arthritis. The Food and Drug Administration (FDA) recently received a report of death in a patient that was associated with inappropriate IV dosing of colchicine. This report prompted further investigation of other deaths associated with IV colchicine use in the FDA Adverse Event Reporting System (AERS) and the medical literature. A total of 20 deaths were identified. Eight patients were females, 11 were males, and the gender was unknown in 1. In all cases, the recommended maximum cumulative dose of 2 to 4 mg during a course of therapy was exceeded. Dose reductions are recommended in patients with renal or hepatic disease and in the elderly. All reported adverse events were associated with colchicine toxicity, including thrombocytopenia, leukopenia, pancytopenia, agranulocytosis, aplastic anemia, acute renal failure, and disseminated intravascular coagulopathy. Death occurred within 1 to 40 days after drug administration. Therapeutic guidelines exist for use of IV colchicine and these guidelines should be followed to prevent serious toxicities and death.     

QTc interval prolongation associated with intravenous methadone

Numerous medications prolong the rate-corrected QT (QTc) interval and induce arrhythmias by blocking ionic current through cardiac potassium channels composed of subunits expressed by the human ether-a-go-go-related gene (HERG). Recent reports suggest that high doses of methadone cause torsades de pointes. To date, no controlled study has described an association between methadone and QTc prolongation. The only commercial formulation of parenteral methadone available in the United States contains the preservative chlorobutanol. The objectives of this study are to determine: (1) whether the administration of intravenous (i.v.) methadone causes QTc prolongation in humans; (2) whether methadone and/or chlorobutanol block cardiac HERG potassium currents (IHERG) in vitro. Over 20 months, we identified every inpatient with at least one electrocardiogram (ECG) performed on i.v. methadone. For each patient, we measured QTc intervals for every available ECG performed on and off i.v. methadone. Concurrent methadone doses were also recorded. Similar data were collected for a separate group of inpatients treated with i.v. morphine. In a separate set of experiments IHERG was evaluated in transfected human embryonic kidney cells exposed to increasing concentrations of methadone, chlorobutanol, and the two in combination. Mean difference (+/- standard error) per patient in QTc intervals on and off methadone was 41.7 (+/- 7.8)ms, p<0.0001. Mean difference in QTc intervals on and off morphine was 9.0 (+/- 6.1)ms, p=0.15. The approximately linear relationship between QTc measurements and log-dose of methadone was significant (p<0.0001). Methadone and chlorobutanol independently block IHERG in a concentration-dependent manner with IC50 values of 20 +/- 2 microM and 4.4 +/- 0.3 mM, respectively. Chlorobutanol potentiates methadone's ability to block IHERG. Methadone in combination with chlorobutanol is associated with QTc interval prolongation. Our data strongly suggest that methadone in combination with chlorobutanol is associated with QTc interval prolongation.     

Myocardial infarction associated with intravenous immune globulin

OBJECTIVE: To report a case of acute myocardial infarction (MI) experienced by a patient receiving intravenous immune globulin (IVIG) and review other published cases of MI associated with IVIG. CASE SUMMARY: An 81-year-old Vietnamese man was prescribed IVIG for treatment of toxic epidermal necrolysis secondary to allopurinol. Thirty minutes following the start of the IVIG infusion, the patient developed crushing retrosternal chest pain and shortness of breath. The pain improved upon discontinuation of IVIG infusion but recurred when IVIG was restarted. The troponin level reached 140 microg/L, and a persantine sestamibi stress test (MIBI) indicated anterolateral ischemia. The patient was diagnos ed with non-ST-elevation MI. An objective causality assessment using the Naranjo probability scale revealed a probable association between this adverse reaction and IVIG treatment. DISCUSSION: Although an association between IVIG administration and MI has not been demonstrated in clinical trials, accumulating clinical experience suggests that a relationship between IVIG and myocardial ischemia exists. Twenty published case reports were identified. Risk of acute MI seems to be increased with use of high-dose IVIG and in older individuals, especially those with at least one cardiovascular risk factor, such as ischemic heart disease or hypertension. CONCLUSIONS: Case reports suggest a causal relationship between the use of IVIG and MI and other thrombotic events. While cardiovascular disease is not considered an absolute contraindication to therapy, expanding indications and subsequent use of IVIG merit that clinicians be aware of patient characteristics that may increase the risk for adverse reactions and recognize early signs of infarction.     

Infection risks associated with needleless intravenous access devices

Needleless intravenous (i.v.) access devices were initially introduced into clinical practice to reduce the rate of i.v. catheter-related needlestick injuries. Their efficacy for this purpose has been confirmed in subsequent reports. However, since their introduction approximately 15 years ago there have been conflicting reports about the risk of i.v. catheter-related bloodstream infection. This article reviews the risk of catheter-related bloodstream infection associated with needleless i.v. access devices and outlines the types of needleless i.v. access devices available.     

Postburn delirium associated with use of intravenous lorazepam

A case of delirium with persecutory delusions is reported, which occurred three days after a previously healthy male suffered burns over 30% of his total body surface area. Routine evaluation was negative for other etiology of delirium, and the symptoms spontaneously remitted within seven hours with no sequella. We found that the benefits and potential side effects of intravenous lorazepam are similar to but of longer duration than those of intravenous diazepam. The effects of intravenous lorazepam should be recognized in the differential diagnosis of postburn delirium in patients given this medication.     

Immunodeficiency associated with motor neuron disease treated with intravenous immunoglobulin

A man with symptoms of amyotrophic lateral sclerosis and immunodeficiency was treated with intravenous immunoglobulin. After four weekly intravenous injections of 2.5 gm of immunoglobulin, his condition showed progressive improvement when measured by clinical, neurological, and physiological parameters. There was a noticeable increase in general physical well-being, an 80% reduction in fasciculations, and the normalization of sensory and motor nerve conduction velocities.