Although gentamicin has been commercially available since 1969, reports concerning the incidence of nephrotoxicity from this drug and variables relating to this toxicity are still unclear and conflicting. In view of this, a prospective study of patients receiving gentamicin over a two month period was undertaken to determine the incidence of nephrotoxicity and to study the influence of several variables on the potential for developing gentamicin associated nephrotoxicity. The variables studied were patient's age; the total grams of gentamicin received; the total number of days the patient received gentamicin with a hemoglobin of less than 12 g%; sex; total days duration of therapy; hemoglobin prior to therapy; hematocrit prior to therapy; red blood cell count prior to therapy; albumin level prior to therapy; and if the patient received another potentially nephrotoxic drug concomitantly with gentamicin. Sixty patients in total were studied. However, in the “toxic” and “nontoxic” grouping process, seventeen patients were excluded from the study due to missing variables. Of the remaining sample, ten patients were classified as “toxic” and thirty-three were classified as “nontoxic.” Thus the incidence of nephrotoxicity was at least 10/60 or 16.7 percent. The data relating to the variables identified were analysed utilizing Chi-square, t-test, and multiple regression analyses. Two variables were found to be highly significant in relationship to the development of nephrotoxicity while receiving gentamicin therapy. These were (1) the albumin level prior to therapy (lower albumin level in the “toxic” group) and (2) the concomitant use of another potentially nephrotoxic drug. The mechanism behind the influence of albumin on gentamicin toxicity is unclear, but may be related to protein binding. The basis for nephrotoxicity relating to combined use of nephrotoxic drugs is probably additive or synergistic toxicity but this is also unclear. Until larger prospective studies concerning gentamicin associated nephrotoxicity provide more meaningful information concerning the significance of the variables involved in this adverse reaction, caution is recommended when using this drug in the albumin deficient patient or in combination with nephrotoxic drugs. In addition, it is further recommended that in patients receiving gentamicin, renal function should be closely monitored and the dosage regimen determined accordingly.
The use of trace-elements in intravenous hyperalimentation solutions has been recommended for long-term therapy. Very little information is available concerning the presence of these nutrients as contaminants in commercially available solutions. In view of this, the concentrations of copper and zinc were measured in twenty solutions by atomic absorption. The results indicate that the amounts present may be significant in certain solutions.
As a care partner for my wife, who has young-onset Parkinson's disease (PD), and as a pharmacist for over 40 years, I would like to comment on the recent case report by Messerschmidt et al.1 about metoclopramide-associated encephalopathy in a patient with PD. It is regrettable that this terrible adverse event had to occur. Metoclopramide is a dopamine antagonist and should be avoided by anyone with PD. Other medications that should be avoided or used with caution in PD patients include typical and atypical antipsychotics (except for quetiapine and clozapine), prochlorperazine, promethazine, droperidol, and amoxa pine.2,3 If a patient with PD is taking a monoamine oxidase B inhibitor such as selegiline or rasagiline, the following drugs should also be avoided: meperidine, tramadol, methadone, cyclobenzaprine, halothane, and dextromethorphan.2,4 Hospital pharmacists must be made aware of the need for timely medication administration in hospitalized patients with PD. Giving medication on time, every time, can help ensure that PD symptoms will continue to be controlled. Any deviation from the patient's normal medication schedule could adversely affect their movement and ability to function.
To the Editor:
As a pharmacist and care partner for my wife who has Parkinson’s disease (PD), I would like to offer the following comments regarding the “Pipeline Plus” feature in P&T (October 2014, pages 712–713) entitled “Steady Progress on Parkinson’s Disease.” This well-intentioned article has two errors/omissions that I would like to point out to your readers.
With regard to the dosage regimen for ropinirole (Requip) in PD: After initial titration, the typical treatment regimen for Parkinson’s disease is 9–24 mg total daily dose (divided three to four times daily).1
In addition, the monoamine oxidase-B (MAO-B) inhibitor selegiline was not included in the table of current therapies. This MAO-B inhibitor has been available for many years and is at least one-tenth the cost of rasagiline (Azilect) but is equally effective.2
I believe that this additional information is important for pharmacists working with PD patients to know.
