P H A R M A G R A M    

...an educational memo from your Pharmacy and Therapeutics Committee

November, 2004

Linezolid (Zyvox®) Interaction with Selective Serotonin Reuptake Inhibitors (SSRIs):

Linezolid is an oxazolidinone class antibiotic usually reserved for use in treating infections caused by vancomycin-resistant E faecium or methicillin-resistant S aureus. Linezolid is also a reversible, nonselective inhibitor of monoamine oxidase and therefore has the potential for interactions with adrenergic and serotonergic agents. Some individuals receiving linezolid may experience a reversible enhancement of the pressor response to indirect-acting sympathomimetic agents, vasopressor or dopaminergic agents. Initial doses of adrenergic agents, such as dopamine or epinephrine, should be reduced and titrated to achieve the desired response. There has now been four reported cases here at SFMC of serotonin syndrome associated with the concomitant use of linezolid and an SSRI (i.e.citalopram (Celexa®), sertraline (Zoloft®), paroxetine (Paxil®), fluoxetine (Prozac®). Physicians should be alert to the possibility of signs and symptoms of serotonin syndrome (e.g. myoclonus, hyperreflexia, diaphoresis, shivering, tremor, diarrhea, incoordination hyperpyrexia, and cognitive dysfunction) in patients receiving such concomitant therapy.

Standardized Concentration for Continuous Insulin Infusions:

In order to reduce the potential for error and in compliance with Joint Commission Standards, a consensus was reached with several medical services to standardize the concentration of insulin infusions to 1 unit/ml.  Insulin infusions in the Neonatal Intensive Care are an exception because of the special patient requirements. The standard adult IV solution consists of 250 units of human, regular insulin in 250ml Normal Saline.

Use the Oral Route for Potassium Replacement Whenever Possible:

Intravenous administration of potassium is associated with greater, and potentially more severe, side effects when compared to the oral route.  Oral administration of potassium is safer and should be considered whenever possible. New guidelines for intermittent IV administration of potassium doses limit the infusion for non-telemetry monitored patients to 10meq/hr for adults and 0.5meq/meq/hr for children.

Drug Shortages and Recalls:

Rofecoxib (Vioxx®) was recently recalled by the manufacturer in response to an increase in cardiovascular events (i.e. strokes and myocardial infarctions) noted in a study they were conducting. Because of this action, the Pharmacy and Therapeutics Committee approved celecoxib (Celebrex®) to the Formulary and established an autosubstitution for valdecoxib Bextra®).  

Influenza Vaccine manufactured by Chiron Pharmaceuticals, which represents about half of the anticipated supply for this season will not be available. The Peoria City County Health Department has been coordinating efforts with other County Health Departments and medical facilities to account for all available vaccine doses and provide criteria for distribution.

Methylprednisolone IV (SoluMedrol®) and betamethasone (Celestone®) supplies are more readily available.  Autosubstitution to dexamethasone has been discontinued for both of these drugs.

Kaopectate® Drug Deletion:

Kaopectate®, which originally contained kaolin and pectin, has been re-formulated several times and it now contains bismuth subsalicylate (same as PeptoBismol®). Because of the confusion resulting from ingredient changes, the P&T Committee has decided to delete this product from the Formulary.

Magnesium Hydroxide (Milk of Magnesia) is Available in Concentrated Form Only

Milk of magnesia (aka MOM) is only available as a TRIPLE concentration solution within the medical center. Orders that do not specify ‘Concentrated’ will be autosubstituted by the pharmacist to the triple-concentrated product using one-third of the ordered volume.

Reminder: Use Your IDX User Number and Signature for Orders

ADE (Adverse Drug Event) Hotline: 655-6805