Drug calculations part 1: a critique of the formula used by nurses

The role of mathematics is integral to nursing practice, and careful and accurate calculations are important to help prevent medication errors. This two-part article examines different methods for solving drug calculation problems. The first part critiques the commonly taught nursing drug calculation formula. Part 2, to be published next week, explores a range of other methods that are used in practice to calculate drug dosages.     

5-methoxy-N,N-di(iso)propyltryptamine hydrochloride (Foxy)-induced cognitive deficits in rat after exposure in adolescence

Foxy or Methoxy Foxy (5-methoxy-N,N-di(iso)propyltryptamine hydrochloride; 5-MeO-DIPT) is rapidly gaining popularity among recreational users as a hallucinogenic “designer drug.”Unfortunately, much remain unknown about the consequences of its use on neuropsychological development or behavior. During one of two adolescent periods, the rats were given repeated injections of 5 mg/kg or 20 mg/kg of 5-MeO-DIPT or a corresponding volume of isotonic saline. After the animals reached adulthood, they were trained and tested on a number of tasks designed to assess the impact of 5-MeO-DIPT, if any, on spatial memory, presumably involving declarative memory systems as well as a nonspatial task that is considered sensitive to disruptions in nondeclarative memory. Both the 5-MeO-DIPT- and saline-treated rats were able to master spatial navigation tests where the task included a single goal location and all groups performed comparably on these phases of training and testing. Regardless of exposure level during adolescence, the performance of the drug-treated rats was markedly inferior to that of the control animals on a task where the goal was moved to a new location and on a response learning task, suggesting a lack of flexibility in adapting their responses to changing task demands. Detected reductions in serotonin activity in the forebrain similar to the effects of extensively investigated compounds such as methylenedioxymethamphetamine (MDMA), suggest that 5-MeO-DIPT may produce its adverse effects by compromising serotonergic systems in the brain.     

Meteorological and hydrological influences on the spatial and temporal prevalence of West Nile virus in Culex mosquitoes, Suffolk County, New York

The factors determining the spatial and temporal distribution of West Nile virus (family Flaviviridae, genus Flavivirus, WNV) activity are not well understood. Here, we explore the effects of hydrological and meteorological conditions on WNV infection among Culex genus mosquitoes collected during 2001-2009 in Suffolk County, Long Island, NY. We show that WNV infection rates in assayed pools of Culex mosquitoes are associated in both space and time with hydrological and meteorological variability. Specifically, wet winter, warm and wet spring conditions, and dry summer conditions are associated with the increased local prevalence of WNV among Culex mosquitoes during summer and fall. These findings indicate that within Suffolk County, and for a given year, areas at risk for heightened WNV activity may be identified in advance by using hydrology model estimates of land surface wetness and observed meteorological conditions.     

Patterns of dietary and herbal supplement use by multiple sclerosis patients

To assess the patterns of dietary (DS) and herbal supplement (HS) use in MS patients, compare use between MS patients and healthy controls and to identify potential interactions with drugs used to treat MS. This study included 279 MS subjects and 161 controls from a study of risk factors in MS. All patients received a neurological examination. All subjects provided responses to a standardized questionnaire administered during an in-person interview. A larger proportion of MS patients (82.1%) compared to controls (60.1%) used one or more DS regularly for at least 3 months (p < 0.001). There was a trend toward a higher proportion of MS patients (26.6%) versus controls (17.8%) who used HSs for more than 1 month (p = 0.038). The most common DS used after MS onset was a multivitamin (78.1%), followed by vitamin D (65.8%). Use of the majority of specific DSs increased significantly after MS onset compared to before. The proportion of controls and MS patients after MS onset who reported using an individual HS was generally similar. The most commonly used HS in patients after MS was evening primrose oil (40.4%) followed by cranberry fruit extract (35.2%). There was no evidence for associations with progressive disease course or with choice of disease-modifying treatment. Dietary supplements are used more frequently by MS patients than controls. Use tends to increase after MS onset compared to before, especially for DS. The use of HS by MS patients is only modestly greater than by controls.     

Ziprasidone- and lithium-induced neuroleptic malignant syndrome

OBJECTIVE: To report a case of ziprasidone- and lithium-induced neuroleptic malignant syndrome (NMS). CASE SUMMARY: A 47-year-old white male with a history of schizoaffective disorder was admitted to the hospital due to an exacerbation of severe mania. He had been taking lithium 450 mg twice daily and divalproex sodium 750 mg/day. On hospital day 2, ziprasidone 80 mg twice daily was added, and as-needed doses of intramuscular ziprasidone 20 mg and lorazepam 2 mg were used for agitation. On day 6, the patient developed hyperthermia (39.4 degrees C), elevated creatine kinase 26,000 units/L and white blood cell (WBC) count (20.7 x 10(3)/microL), myoglobinuria, hypotension (68/40 mm Hg), altered mental status, and tachypnea (28 breaths/min). This case is notable for the absence of muscle rigidity, which presents in greater than 90% of patients with NMS taking traditional antipsychotics. DISCUSSION: This case of ziprasidone- and lithium-induced NMS is of probable cause, as determined by the Naranjo probability scale. The patient presented with symptoms consistent with NMS 4 days after initiation of ziprasidone and lithium. The majority of NMS cases present with the core features of hyperthermia, muscle rigidity, and elevated CK levels. Other frequently seen symptoms include altered mental status, tachypnea, tachycardia, elevated WBC count, hypotension, diaphoresis, and myoglobinuria. Our patient presented with 2 of the core symptoms, but did not develop muscle rigidity at any time. NMS criteria include muscle rigidity as one of the major presenting symptoms. Recent literature suggests that perhaps NMS due to novel antipsychotics presents with less muscle rigidity than is seen with traditional agents due to their lower affinity for the dopamine D2 receptor. CONCLUSIONS: This case illustrates that NMS due to the novel antipsychotic ziprasidone may present with many of the core symptoms of the syndrome, but possibly less muscle rigidity than is seen with traditional agents.     

Nursing implications of androgen deprivation therapy-associated bone loss

Men with locally advanced and nonmetastatic prostate cancer are generally treated with androgen deprivation therapy (ADT) to suppress tumor growth. This treatment, however, is associated with decreased bone density and increased fracture risk, which can lead to increased morbidity and mortality. Nurses play a key role in patient education by promoting lifestyle changes such as diet and exercise that can improve bone strength and decrease risk of ADT-associated bone loss. Pharmacologic interventions using bisphosphonates can significantly reduce bone loss and fracture risk in patients with prostate cancer receiving ADT.