PHARMACY

Are We Speaking the Same Language?

Michael J. Gaunt, PharmD

Dr. Gaunt is a medication safety analyst and the editor of ISMP Medication Safety Alert! Community/Ambulatory Care Edition.

The Problem

Many people, even health care professionals, have trouble functioning well as patients—whether limited by knowledge, emotional or clinical state, socioeconomic factors, cultural background, or language differences. The television show ER portrayed this problem in an episode in which a Spanish-speaking woman misunderstood the directions for taking isoniazid (INH). The prescription label stated to take the medication “once” daily. In the Spanish language, however, “once” means “eleven.” In the show, the patient died from taking such an excessive dose.

A similar, real-life problem occurred when a Spanish-speaking mother applied oxiconazole 1% cream (Oxistat) to her baby’s inflamed rash up to 11 times each day. The mother was simply following prescription label directions that stated, half in English and half in Spanish, “Aplicarse once cada dia til rash is clear.” The problem is that “once” means “eleven” in Spanish. Fortunately, this was a topical medication, and while the inflammation got worse, no permanent harm resulted. Had this been an oral medication, however, the outcome could have been much more serious.

When a pediatric patient with seizures was discharged from the hospital, the physician wrote the following prescription: “phenytoin suspension 30 mg/5 mL, take 5.8 cc three times a day.” Since the patient and his family spoke only Spanish, the nurse gave the patient’s mother the written prescription and an oral syringe marked with tape at the 5.8 mL mark. Because phenytoin suspension is no longer commercially available in the 30 mg/5 mL concentration, however, the pharmacy where the mother took the prescription filled it with phenytoin 125 mg/5 mL. The prescription was labeled correctly and stated that the patient was to be given 1.3 mL 3 times a day. The pharmacist, who did not speak Spanish, could not counsel the patient’s mother. As a result, the mother used the syringe the nurse had given her, and she administered 145 mg 3 times a day instead of 34.8 mg 3 times a day. A few days later, the patient was readmitted to the hospital intensive care unit nearly comatose with phenytoin toxicity. The child recovered and was discharged.

In another example, a physician prescribed “Amoxicillin 200 mg/5 mL” with instructions to administer 5 mL tid to a 3-year-old child. The pharmacy carried only a 250 mg/5 mL strength, so the pharmacist changed the directions to “Take 4 cc (4/5 teaspoonful) by mouth 3 times a day.” The child’s father misunderstood the directions, as English was his second language. He did not know what “cc” meant, but upon seeing “4/5 teaspoonful,” he thought he should give his child 4.5 teaspoons of the medication. After 5 doses, he brought his child to the emergency department with severe diarrhea. The use of 2 abbreviations—“cc” and a slash mark (/)—contributed to the error. The child’s father did not interpret either abbreviation as intended. Inadequate patient counseling also played a role. Although he had been given a 10 mL measuring device for oral solutions marked in mL and teaspoons, specific directions for measuring each dose were not reviewed with the father when he picked up the prescription.

Safe Practice Recommendations

Patient counseling is always important, especially if a pharmacist must use a different concentration of a drug than originally prescribed because the directions that the physician initially provided to the patient differed from the actual directions on the prescription label. If the patient—or the family, in the case of a pediatric patient—does not speak English, however, it is a difficult situation. If you have a lot of patients who speak another language, consider having patient information brochures already translated into that language. While oral and written instructions are definitely preferred, for those patients who speak other languages written brochures may be the only way to provide counseling.

ELECTRIC CIRCUITS

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You might have been wondering how electrons can continuously flow in a uniform direction through wires without the benefit of these hypothetical electron Sources and Destinations. In order for the Source-and-Destination scheme to work, both would have to have an infinite capacity for electrons in order to sustain a continuous flow! Using the marble-and-tube analogy, the marble source and marble destination buckets would have to be infinitely large to contain enough marble capacity for a “flow” of marbles to be sustained.

The answer to this paradox is found in the concept of a circuit: a never-ending looped pathway for electrons. If we take a wire, or many wires joined end-to-end, and loop it around so that it forms a continuous pathway, we have the means to support a uniform flow of electrons without having to resort to infinite Sources and Destinations:

each electron advancing clockwise in this circuit pushes on the one in front of it, which pushes on the one in front of it, and so on, and so on, just like a hula-hoop filled with marbles. Now, we have the capability of supporting a continuous flow of electrons indefinitely without the need for infinite electron supplies and dumps. All we need to maintain this flow is a continuous means of motivation for those electrons, which we’ll address in the next section of this chapter.

It must be realized that continuity is just as important in a circuit as it is in a straight piece of wire. Just as in the example with the straight piece of wire between the electron Source and Destination, any break in this circuit will prevent electrons from flowing through it:

An important principle to realize here is that it doesn’t matter where the break occurs. Any discontinuity in the circuit will prevent electron flow throughout the entire circuit. Unless there is a continuous, unbroken loop of conductive material for electrons to flow through, a sustained flow simply cannot be maintained.

 

·         REVIEW:

·         A circuit is an unbroken loop of conductive material that allows electrons to flow through continuously without beginning or end.

·         If a circuit is “broken,” that means it’s conductive elements no longer form a complete path, and continuous electron flow cannot occur in it.

·         The location of a break in a circuit is irrelevant to its inability to sustain continuous electron flow. Any break, anywhere in a circuit prevents electron flow throughout the circuit.

Voltage and current in a practical circuit

Because it takes energy to force electrons to flow against the opposition of a resistance, there will be voltage manifested (or “dropped”) between any points in a circuit with resistance between them. It is important to note that although the amount of current (the quantity of electrons moving past a given point every second) is uniform in a simple circuit, the amount of voltage (potential energy per unit charge) between different sets of points in a single circuit may vary considerably:

Take this circuit as an example. If we label four points in this circuit with the numbers 1, 2, 3, and 4, we will find that the amount of current conducted through the wire between points 1 and 2 is exactly the same as the amount of current conducted through the lamp (between points 2 and 3). This same quantity of current passes through the wire between points 3 and 4, and through the battery (between points 1 and 4).

However, we will find the voltage appearing between any two of these points to be directly proportional to the resistance within the conductive path between those two points, given that the amount of current along any part of the circuit’s path is the same (which, for this simple circuit, it is). In a normal lamp circuit, the resistance of a lamp will be much greater than the resistance of the connecting wires, so we should expect to see a substantial amount of voltage between points 2 and 3, with very little between points 1 and 2, or between 3 and 4. The voltage between points 1 and 4, of course, will be the full amount of “force” offered by the battery, which will be only slightly greater than the voltage across the lamp (between points 2 and 3).

This, again, is analogous to the water reservoir system:

 

Between points 2 and 3, where the falling water is releasing energy at the water-wheel, there is a difference of pressure between the two points, reflecting the opposition to the flow of water through the water-wheel. From point 1 to point 2, or from point 3 to point 4, where water is flowing freely through reservoirs with little opposition, there is little or no difference of pressure (no potential energy). However, the rate of water flow in this continuous system is the same everywhere (assuming the water levels in both pond and reservoir are unchanging): through the pump, through the water-wheel, and through all the pipes. So it is with simple electric circuits: the rate of electron flow is the same at every point in the circuit, although voltages may differ between different sets of points.