1. Section Editor(s): Cohen, Michael R. RPh, MS, ScD

Article Content

Many patients use U-100 insulin syringes to self-administer methotrexate, an antimetabolic drug that can be used to treat severe rheumatoid arthritis and psoriasis. When they're hospitalized, patients may miscommunicate their usual dosage to health care providers.


Patients using a U-100 insulin syringe may report the amount of medication they take according to the unit scale on the insulin syringe, which isn't the actual methotrexate dosage. Health care providers may misinterpret this number as milligram or volume amounts. In one case, a patient's family told the hospital staff that the patient took 80 mL of methotrexate once a week. The patient, who'd been using a U-100 insulin syringe, was measuring 80 units on the syringe scale, which amounted to 0.8 mL of methotrexate-a hundredfold difference.


To be safe when obtaining a methotrexate dose during medication reconciliation or when taking a medication history, ask the patient which administration device he uses. Verify dosing information provided by patients and family, especially if the dose is unusual or unexpected.


Components of an independent double check

Two clinicians separately check each component of prescribing, dispensing, and administering a high-alert medication:


Comparison to prescriber's order

Figure. No caption a... - Click to enlarge in new windowFigure. No caption available.

* Is this the prescribed drug?


* Is this the prescribed dose/strength/infusion rate?


* Is this the prescribed administration route?


* Is this the right patient?


* Is this the prescribed frequency/time for administration?



Additional cognitive checks


* Does the drug's indication match the patient's diagnoses or conditions?


* Is this the right formulation of the drug?


* Are the dose calculations correct?


* Is the dosing formula used to derive the dose correct (mg/kg)?


* Is the prescribed dose appropriate for this patient?


* Is the dosing frequency/timing appropriate for this patient?


* Is the administration route safe and proper for this patient?


* Are pump settings (if applicable) correct?


* Is the infusion line attached to the correct port (if applicable)?


* Have appropriate monitoring tests and guidelines been ordered and checked?