DƯỢC LÍ Goodman & Gilman's The Pharmacological Basis of Therapeutics 12th, 2010

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APPENDIX I
PRINCIPLES OF PRESCRIPTION ORDER WRITING AND PATIENT COMPLIANCE
Table AI–1
Controlled Substance Schedules
Schedule I (examples: heroin, methylene dioxymethamphetamine,
lysergic acid diethylamide, mescaline, and all
salts and isomers thereof):
1. High potential for abuse.
2. No accepted medical use in the U.S. or lacks accepted
safety for use in treatment in the U.S. May be used for
research purposes by properly registered individuals.
Schedule II (examples: morphine, oxycodone, fentanyl,
meperidine, dextroamphetamine, cocaine, amobarbital):
1. High potential for abuse.
2. Has a currently accepted medical use in the U.S.
3. Abuse of substance may lead to severe psychological
or physical dependence.
Schedule III (examples: anabolic steroids, nalorphine,
ketamine, certain schedule II substances in suppositories,
mixtures, or limited amounts per dosage unit):
1 Abuse potential less than substances in schedule I or
schedule II.
2. Has a currently accepted medical use in the U.S.
3. Abuse of substance may lead to moderate to low physical
dependence or high psychological dependence.
Schedule IV (examples: alprazolam, phenobarbital,
meprobamate, modafinil):
1. Abuse potential less than substances in schedule III.
2. Has a currently accepted medical use in the U.S.
3. Abuse of substance may lead to limited physical or
psychological dependence relative to substances in
schedule III.
Schedule V (examples: buprenorphine, products containing
a low dose of an opioid plus a non-narcotic ingredient
such as cough syrup with codeine a and guaifenesin, antidiarrheal
tablets with diphenoxylate and atropine):
1. Low potential for abuse relative to schedule IV.
2. Has a currently accepted medical use in the U.S.
3. Some schedule V products may be sold in limited
amounts without a prescription at the discretion of the
pharmacist; however, if a physician wishes a patient to
receive one of these products, it is preferable to provide
a prescription.
a
Although codeine is a schedule II drug, its dosage in cough syrups is
regarded as sufficiently low to permit their classification as schedule
V substances.
A statement such as “refill prn” (refill as needed) is not
appropriate, as it could allow the patient to misuse the
medicine or neglect medical appointments. If no refills
are desired, “zero” (not “0”) should be written in the
refill space to prevent alteration of the prescriber’s
intent. Refills for controlled substances are discussed
later, in “Refills” under “Controlled Substances.”
Concern about the rising cost of healthcare has
favored the dispensing of so-called “generic” drugs. A
drug is called by its generic name (in the U.S., this is the
U.S. Adopted Name or USAN) or the manufacturer’s
proprietary name, called the trademark, trade name, or
brand name. In most states in the U.S., pharmacists
have the authority to dispense generic drugs rather than
brand-name medications. The physician can request
that the pharmacist not substitute a generic for a
branded medication by indicating this on the prescription
(“do not substitute”), although this generally is
unnecessary because the U.S. Food and Drug
Administration (FDA) requires that generic medications
meet the same bioequivalence standards as their
brand-name counterparts. In some jurisdictions, prescriptions
may not be filled with a generic substitution
unless specifically permitted on the prescription.
Occasions when substituting generic medications is discouraged
are limited to products with specialized
release systems and narrow therapeutic indices, or
when substantial patient confusion and potential noncompliance
may be associated with substitution.
Choice and Amount of Drug Product
Dispensed
Inappropriate choice of drugs by physicians is a problem
in prescribing. As learned recently with the
cyclooxygenase-2 (COX-2) inhibitors, a drug’s therapeutic
promise or popularity is not proof of its overall
clinical superiority or safety (Topol, 2004). Physicians
must rely on unbiased sources when seeking drug information
that will influence their prescribing habits; use
of the original medical literature will ensure instruction
of the prescriber’s best judgment.
The amount of a drug to be dispensed should be
clearly stated and should be only that needed by the
patient. Excessive amounts should never be dispensed,
because this not only is expensive for the patient but
may lead to accumulation of medicines, which can lead
to harm to the patient or members of the patient’s family
if used inappropriately. It is far better to have several
refills of a prescription than to have more than necessary
prescribed at one time.
The Prescription as a Commodity
Prescribers must be aware that patients may visit their
doctor to “get” a prescription. Indeed, in an era when
the time spent between physician and patient is ever