The directions for use (element [11]) must be both drug-specific and patient-specific. The simpler the directions, the better; and the fewer the number of doses (and drugs) per day, the better. Patient noncompliance (also known as nonadherence, failure to adhere to the drug regimen) is a major cause of treatment failure. To help patients remember to take their medications, prescribers often give an instruction that medications be taken at or around mealtimes and at bedtime. However, it is important to inquire about the patient’s eating habits and other lifestyle patterns, because many patients do not eat three regularly spaced meals a day.
The instructions on how and when to take medications, the duration of therapy, and the purpose of the medication must be explained to each patient both by the prescriber and by the pharmacist. (Neither should assume that the other will do it.) Furthermore, the drug name, the purpose for which it is given, and the duration of therapy should be written on each label so that the drug may be identified easily in case of overdose. An instruction to “take as directed” may save the time it takes to write the orders out but often leads to noncompliance, patient confusion, and medication error. The directions for use must be clear and concise to prevent toxicity and to obtain the greatest benefits from therapy.
Although directions for use are no longer written in Latin, many Latin apothecary abbreviations (and some others included below) are still in use. Knowledge of these abbreviations is essential for the dispensing pharmacist and often useful for the prescriber. Some of the abbreviations still used are listed in Table 65–1.
Note: It is always safer to write out the direction without abbreviating.
Elements [12] to [14] of the prescription include refill information, waiver of the requirement for childproof containers, and additional labeling instructions (eg, warnings such as “may cause drowsiness,” “do not drink alcohol”). Pharmacists put the name of the medication on the label unless directed otherwise by the prescriber, and some medications have the name of the drug stamped or imprinted on the tablet or capsule. Pharmacists must place the expiration date for the drug on the label. If the patient or prescriber does not request waiver of childproof containers, the pharmacist or dispenser must place the medication in such a container. Pharmacists may not refill a prescription medication without authorization from the prescriber. Prescribers may grant authorization to renew prescriptions at the time of writing the prescription or over the telephone or electronically. Elements [15] to [17] are the prescriber’s signature and other identification data such as National Provider Identification (NPI), Drug Enforcement Administration (DEA) number, or State License number.
Unfortunately, prescribing errors are common. Several groups provide online information regarding practices designed to reduce or document such errors, eg, Institute for Safe Medication Practices (ISMP; http://www.ismp.org/) and National Coordinating Council for Medication Error Reporting and Prevention Program (MERP; http://www.nccmerp.org/about-medication-errors).
TABLE 65–1 Abbreviations used in prescriptions and chart orders.
agit shake, stir
D5W, D5W dextrose 5% in water disp, dis dispense mEq, meq milliequivalent qh, q1h rept, repet tbsp, T (do not use)
Tr, tinct i, ii, iii, iv, etc by mouth one, two, three, four, etc dram (in fluid measure 3.7 mL) ounce (in fluid measure 29.6 mL) cap capsule q2h, q3h, etc every 2 hours, every 3 hours, etc gtt drops SC, SQ subcutaneous hs at bedtime Sig, S label
IM intramuscular ss, ss one-half
IVPB IV piggyback sup, supp suppository mcg, μg (do not use) microgram (always write out “microgram”) tab tablet
OS, OL left eye vag vaginal