Principles of Prescription Writing

1
Principles of Prescription Writing

• Nicholas G Popovich Ph.D., R.Ph.
• Professor and Head
• Department of Pharmacy Administration
• UIC College of Pharmacy

2
Objectives

• Define a prescription and the classification of
  medications
• Compare and contrast the various schedules of
  controlled substances
• Compare and contrast a prescription medicine and
  a non-prescription medicine
• List the component elements of the prescription

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Objectives contd

• List the component elements of a controlled
  substance prescription
• Classify controlled drugs by their schedule
• Describe writing conventions associated with
  prescription writing
• Provide examples of look alike, sound alike
  prescription medicines, including trade names

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Objectives contd

• Provide examples of confusing abbreviations used
  in prescription writing
• Describe important prescription writing
  precautions for traditional and controlled
  substance prescriptions
• Define the off label use of a drug

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Prescription Order Writing

• Definition A prescription is a written, verbal,
  or electronic order from a prescriber (e.g.,
  physician, dentist, podiatrist, nurse
  practitioner) to a pharmacist for a particular
  medication for a specific medication at a certain
  time.

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Classification of Medications

• Prescription legend drug or medication
• Prescription product label reads
• Caution Federal Law Prohibits Dispensing
  without a Prescription.

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Types of Prescriptions

• Generic? The nonproprietary name provided by the
  United States Adopted Name (USAN) Council
• syn. Chemical Name
• e.g., amoxicillin, fluoxetine, diazepam, aspirin
• Brand Name? The proprietary name or registered
  trademark name provided by the pioneer
  (innovator) pharmaceutical company who holds the
  patent on the drug
• e.g., Prozac, Viagra, Xanax

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Types of Prescriptions contd

• Compounded? Requires the preparation of one or
  more active ingredients with one or more
  pharmaceutical necessities, e.g., suspending
  agent, flavoring agent, to create a finished
  product.
• For example, an oral compounded prescriptions
  may be used to facilitate the administration of a
  solid dosage form that is not available in liquid
  form for patients unable to swallow a solid
  dosage form.
• e.g., pediatric, geriatric

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Types of Prescriptions contd

• Control Substance? Distribution of certain
  medicines with abuse potential is controlled
  through the Comprehensive Drug Abuse Prevention
  and Control Act of 1970
• This Act is regulated and enforced by the
  federal Drug Enforcement Agency (DEA)
• MDs must be registered with the DEA to prescribe
  those drugs under the control of this act.
• Re-registration is mandatory every three years.
• A partial listing of controlled substances is
  demonstrated in Appendix A. Further examples of
  drugs by schedule are found at http//www.dea.gov/
  pubs/scheduling.html

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Types of Prescriptions contd

• New? An original prescription order dispensed for
  the first time.
• Refill? A repeat dispensing of the original
  prescription order.
• Usually, encompasses patients on maintenance
  therapy, e.g., digoxin, phenytoin, lovastatin,
  potassium chloride.

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Schedules of Controlled Substances

• Schedule I ? No medical use with a high abuse and
  dependence potential
• A physician cannot write for this schedule of
  drugs
• e.g., LSD, Marijuana, Heroin, Mescaline
  (Peyote), 1-(1-Phenylcyclohexyl)pyrrolidine
  (i.e., PCP).
• Twelve states have laws regulating the medical
  use of marijuana- AL, AZ, CA, CO, HI, ME, MD, MT,
  NV, OR, VT, WA

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Schedules of Controlled Substances

• Schedule II ? A written prescription is required
  for this schedule. However, there are no refills
  allowable.
• Only in an emergency situation is an oral order
  allowable and acceptable to the dispenser.
• Must be followed by a written prescription within
  72 hours.
• In some states (formerly IL), the physician must
  complete a triplicate prescription form to
  prescribe Class II in ink.
• The physician should write out the actual amount
  prescribed besides giving an Arabic Number or
  Roman Numeral for the quantity.
• This discourages forging or alteration of the
  prescription.
• In Illinois, a written prescription for this
  schedule must be dispensed within 7 days of
  issuance or it expires.
• e.g., amphetamines, meperdine HCl, cocaine,
  oxycodone, secobarbital sodium

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Multiple Prescriptions for Schedule II Controlled
SubstancesDEA Rule

• 12/19/07 Approved federal legislation to allow
  prescriber to write gt1 prescriptions (not more
  than a 90 day supply total) for CII controlled
  substances in certain circumstances.
• ? Legitimate medical purpose.
• ? Instruction on each prescription indicating
  earliest date to dispense the prescription.
• ? This situation does not create an undue risk
  of diversion or abuse.
• ? Applicable state laws permit this practice
  (Not in Illinois).
• ? Prescriber is in compliance with all other
  state and federal laws.

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Schedules of Controlled Substances

• Schedule III? Drugs in this schedule have a
  moderate abuse and dependence potential
• May be prescribed in writing or through a verbal
  order.
• May be refilled up to five times within a six
  month interval from the date of issuance.
• e.g., glutethimide, chlorphentermine,
  phenmetrazine, anabolic steroids

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Schedules of Controlled Substances

• Schedule IV? Drugs in this schedule are
  considered to have low abuse and low dependency
  potential
• May be prescribed through writing and through a
  verbal order.
• May be refilled upto five times within a six
  month interval from the date of issuance.
• E.g., alprazolam (Xanax), pentazocine (Talwin),
  flurazepam (Dalmane)

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Schedules of Controlled Substances

• Schedule V? Drugs in this schedule have the least
  amount of abuse potential and an unlikely
  dependency
• Consists primarily of medications that contain
  limited quantities of certain narcotic and
  stimulant drugs generally used as anti-tussives,
  antidiarrheals, and analgesics
• Can be purchased OTC by the patient who signs a
  registry
• e.g., Robitussin AC, Parepectolin, Kaopectolin PG
• Technically, applies to pseudoephedrine purchases.

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Nonprescription Medications

• Can be purchased at pharmacies and retail outlets
  without a prescription (syn. Over-the-counter
  OTC products)
• To date, 99 drugs and/or drug dosage forms have
  been switched from prescription to OTC status
  (Note Appendix AA)
• Besides South Africa, the US is the only country
  NOT to have a third class of drugs. That is,
  available through the pharmacist.
• FL has a pharmacist only class of medications
• BTC being considered by FDA

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National Coordinating Council for Medication
Error Reporting and Prevention (NCC-MERP) --
Founding Members

• American Association of Retired PersonsAmerican
  Health Care AssociationAmerican Hospital
  AssociationAMA American Nurses Association
  American Pharmacists Association American
  Society of Health-System Pharmacists FDA GPIA
  JCAHO National Association of Boards of
  Pharmacy National Council of State Boards of
  Nursing, Inc PhRMA United States Pharmacopeia

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NCC-MERP Recommendations to Improve Error-Prone
Aspects of Prescription Writing

• All prescriptions must be legible. Prescribers
  should move to a direct, computerized, order
  entry system.Handwriting examples

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Can you read this?
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Component Elements of the Prescription

• Heading? Physicians name, practice address and
  telephone number, DEA number
• Date prescription is written
• Patient Information? Name, address, age (esp., if
  for a pediatric or geriatric patient) or Date of
  Birth (DOB)

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Component Elements of the Prescription

• Body of the Prescription (Note Exhibit)
• RX? Take Thou. Name of the prescribed drug or
  drug product. Also included is the strength of
  the medication, the number or quantity of the
  prescribed drug in addition to the dosage form
• DO NOT use abbreviations for drugs prescribed
  unless the abbreviation is official, e.g., SSKI
  (Saturated Solution of Potassium Iodide), NSS
  (Normal Saline Solution), HCTZ (Hydrochlorothiazid
  e), NTG (Nitroglycerin), MTX (Methotrexate)
• Avoid unofficial abbreviations

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Many drugs come in several concentrations and
sizes of containers. Prescribe only by
metric weight, not number (or ) of "cc's",
"amps", "vials (is above order for digoxin
0.1mg/mL or 0.25mg/mL?)
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Component Elements of the Prescription - Body of
the Prescription (contd)

• Sig? Signatura (i.e., Mark Thou). Directions for
  use, e.g., one cap every 8 hrs.
• Avoid ut dictum or as directed. Units should
  be spelled out rather than writing U.
• Latin abbreviations (Appendix B) are acceptable
  as well as plain English
• Commonly confused Latin abbreviations include
  qd, qod
• Refills? N times or NR. Leaving this section
  blank implies that the prescription is non-
  refillable.

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A handwritten "u" can look like a zero, a four,
or "cc." Always write out "unit." (all three
problems illustrated above)
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Dangerous Abbreviations

• Abbreviation ? Intended Meaning
• U ? Units
• µg ? Micrograms
• Q.D. ? Every day
• Q.O.D. ? Every other day
• MS, MSO4, ? Morphine sulfate or
• MgSO4 magnesium sulfate?

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The abbreviation "q.d." can sometimes look
like "q.i.d." Always spell out the word "daily."
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More Dangerous Abbreviations

• SC or SQ ? Subcutaneous
• TIW ? Three times a week
• D/C ? Discharge discontinue
• HS ? Half strength bedtime?
• cc ? Cubic centimeters
• AU, AS, AD ? Both ears, left ear, right ear
• I.U. ? International units

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Component Elements of the Prescription - Body of
the Prescription (contd)

• Generic Authorization? Physician signature on the
  dispense as written or may substitute line
• No Child Resistant Packaging Authorization? All
  legend drugs intended for oral use must be
  dispensed by the pharmacist to the patient in
  containers having safety closures unless the
  prescribing physician or the patient specifically
  requests otherwise.
• A request for a non-child resistant container may
  be applied to a single prescription or to all of
  the patients dispensed medications.
• The pharmacist should clarify the patients
  desires, obtain and file a signed waiver request,
  and maintain the information in the prescription
  computer for future reference.
• Exception Nitroglycerin (NTG) containing
  products.

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Component Elements of the Prescription - Body of
the Prescription (contd)

• Signature? Legible in indelible pencil or pen.
  Signature selections
• May substitute_______________________
• Dispense as written___________________
• DEA Number? If necessary and, sometimes found
  within the heading of the prescription blank
  along with the physicians practice information

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Writing Conventions

• For compounded prescriptions, when units are not
  given, solids are assumed to be in grams (g) and
  liquids in milliliters (ml).
• Never write a decimal without a zero preceding
  it, e.g., 0.15 g Clindamycin HCl. This helps to
  minimize an error in translation
• Never write a decimal with a zero following it,
  e.g., Propylene Glycol 6.0, Propylene Glycol 6
• e.g., Rx Clindamycin HCl 0.15
• Propylene Glycol 6
• Lavacol qsad 30
• Sig Apply aa bid

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Avoid a tenfold overdose. Place a zero before
the decimal point.
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Avoid potential tenfold overdoses. Never follow
drug doses with a decimal point and
zero. (example of 1mg was read as 10 mg)
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Writing Conventions (contd)

• Sometimes a vertical line is used for the decimal
  point, although, conceivably, it could be
  confused as a number one.
• ____
• e.g., Rx Chlorpheniramine 0 l 002
• Aspirin 0 l 325
• d.t.d. Caps 12
• Sig i cap po q.i.d allergy and pain

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Writing Conventions (contd)

• Liquid household measures
• Milliliter ml
• 1 teaspoonful 5 ml
• 1 tablespoonful 15 ml
• 2 tablespoonfuls 30 ml (approximately one
  ounce)
• 8 fluid ounces 240 ml
• One pint 16 fluid ounces 473 ml
• One quart 32 fluid ounces 946 ml
• One gallon 4 quarts 8 pints 3750 ml
• gtts drops (e.g., oral, ophthalmic, ear,
  topical)

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Writing Conventions (contd)

• Solid weights
• mcg microgram
• mg milligram
• g gram
• gr grain (old apothecary system reserved
  for older, traditional medications).
• Note for these one grain is equal to 60 mg.
  Otherwise, one grain 64.8 mg.
• e.g., nitroglycerin, 1/150 gr, 1/200 gr, 1/400
  gr
• phenobarbital, ¼ gr., ½ gr.,1 gr.
• thyroid ¼ gr, ½ gr, 1 gr.

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Writing Conventions (contd)

• Be very cautious about drug names that
  sound/look alike (Appendix C).
• http//www.nacds.org/wmspage.cfm?parm11915
• Avoid using unofficial abbreviations for
  drugs/drug product names, e.g., PCN (Penicillin),
  SMX-TMP (Sulfamethoxazole-Trimethoprim), TCN
  (Tetracycline), KCl (Potassium Chloride), MOM
  (Milk of Magnesia). If confused, contact the
  pharmacist.

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Prescription Writing Suggestions

• Intended to ensure patient safety and minimize
  pharmacist intervention on behalf of the
  prescriber and the patient.
• Keep all prescription blanks in a safe place out
  of patient reach. This avoids the temptation and
  disappearance of blanks. Further, this procedure
  minimizes the number of prescription pads in use.
• Use a separate prescription blank for each
  prescribed medication.

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Prescription Writing Suggestions

• Ensure that refill directions are included on
  every prescription. Is it refillable or not?
  
• If refillable, indicate the number of times or
  the duration of time that refills are authorized.
  It will save the prescriber time and
  interruptions in the long run. Legally, aside
  from refill limitations associated with
  controlled substances, a prescription refill for
  a conventional, non-controlled medication has a
  one year expiration time.

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Prescription Writing Suggestions

• Attempt to make the prescription order alteration
  proof.
• Use indelible pencil or ink and for controlled
  substances write the number and spell it out.
  Otherwise, for example, a XII can be forged to
  read XXX. Use the same pen or indelible pencil
  for the entire prescription. If a mistake is
  made, e.g., number of tablets, cross out the
  mistake, write/print error above it, and then
  initial it.

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Prescription Writing Suggestions

• Avoid writing a prescription for a large quantity
  of drug unless it is absolutely determined that
  such a quantity is necessary.
• For an anticipated chronic medication, it is
  better to start with a lower number at first in
  the event that the patient cannot tolerate it
  because of side effects. Think also of the
  economic considerations. Insurance plans will
  limit the amount to one to three months at most.
• When an institutional prescription blank is used,
  the prescriber should clearly print his/her name,
  address, DEA registration number on the blank.

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Prescription Writing Suggestions for Controlled
Substances

• Again, this is intended to ensure patient safety
  and minimize pharmacist intervention on behalf of
  the prescriber and the patient.
• Use a separate prescription blank for each
  substance prescribed.
• Maintain only a minimum stock of controlled
  substances in the medical bag, and it should be
  taken by the physician while away from the
  automobile. Keeping the medical bag locked in the
  automobile trunk is not always an effective
  deterrent.

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Prescription Writing Suggestions for Controlled
Substances

• During the drug history, if a patient concedes
  that he/she has received a controlled substance
  prescription from another physician, consult that
  physician or the hospital records, and/or examine
  the patient to decide if a controlled substance
  should be prescribed.
• Do not allow the patient to dictate the
  controlled substance, if any, to be prescribed.
  The patient may be doctor shopping.
• Maintain an accurate record of controlled
  substance products dispensed as required by the
  Controlled Substances Act.

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Prescription Writing Suggestions for Controlled
Substances

• A prescription order blank should only be used
  for writing the prescription.
• Do not use it to write a note and/or information
  for the patient. An unscrupulous drug dealer or
  abuser could erase the information easily and use
  the blank to forge a prescription drug.

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Prescription Writing Suggestions for Controlled
Substances

• The prescriber should use the pharmacist as a
  valuable resource when needed. Also, assist the
  pharmacist when he/she inquires to verify
  information about a prescription order. A
  corresponding responsibility/liability rests with
  the pharmacist who dispenses the prescription
  order.
• Telephone the nearest DEA field office to secure
  and/or furnish information. The call is held in
  strictest confidence.

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Unlabeled (syn Off-Label) Use (Indication)

• Serendipitous observations (e.g., decreased
  migraine headache attacks while maintained on
  ß-blockers for cardiovascular therapy sildenafil
  citrate clinically evaluated for lowering blood
  pressure demonstrating use for erectile
  dysfunction) and therapeutic interventions of
  physicians have led to medicines being prescribed
  for unlabeled use for which the drug has not been
  approved by the FDA.
• The off-label use is supposed to be based upon a
  rational scientific theory, expert medical
  opinion, or evidence based on sound clinical
  trial(s).

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Unlabeled (syn Off-Label) UseCommonly
used for depression, cancer, HIV/AIDS,dermatologi
cal disorders, and migraine.Common in the
pediatric populationdanger ? AEs.In 2001,
73 off label prescriptions were not supported
by scientific evidence.
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Unlabeled (syn Off-Label) Use (Indication)

• The FDA makes clear that it neither has, nor
  desires, the authority to compel physicians to
  adhere to only official labeled indications.
  Simply, experience has demonstrated that the
  official indications lag behind scientific
  knowledge and the scientific/medical literature.

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Unlabeled (syn Off-Label) Use (Indication)

• A Supplemental New Drug Application (NDA) may be
  filed by the drug manufacturer when approval is
  sought for an additional indication for a drug
  already approved for another indication. It has
  been estimated that 40 of all prescriptions are
  written for indications for which a Supplemental
  NDA has not been filed. While this process is
  less demanding, drug manufacturers do not want to
  invest the time, energy, and to do so.
• Consequently, this has resulted in 75 to 90
  off-label prescribing for infants and children.
  The caveat is less than desirable dosing and
  warnings for the pediatric patient with increased
  incidence of adverse effects.

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Single Patient Compassionate Use

• A FDA-requested mechanism for a physician to use
  a drug in a single patient, usually in a
  desperate situation when there is no response to
  other therapies or in which there is no approved
  or recognized treatment available.

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Single Patient Compassionate Use

• Approval for a compassionate use may be sought in
  the following situations when a(n)
• IND is in effect, but the drug is still in the
  early stages of testing.
• IND is in effect, but the intent of the drug use
  is not for the purpose described in the IND.
• drug has an IND, but it is not marketed.
• drug has had previous FDA approval but has been
  withdrawn from the market because of questions
  regarding its safety.
• drug is being investigated or marketed outside of
  the US, but no IND is in effect within the US.
• Often, the FDA will permit the proposed use under
  a commercial sponsors IND or under a new IND
  filed by the physician in behalf of an identified
  patient.

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References

• Scott SA. The Prescription, in Remington The
  Science and Practice of Pharmacy, 21st Edition,
  A. Gennaro, Chairman, Editorial Board and Editor,
  Lippincott Williams and Wilkins, Baltimore MD,
  2005, pp. 1823-1839.
• http//www.dea.gov/pubs/scheduling.html
• http//www.nacds.org/wmspage.cfm?par
• m11915
• Updated March 23, 2009

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Acknowledgement Examples scanned from
materials prepared by the Institute for Safe
Medication PracticesISMP, Warminster,
PAMichael Cohen, President
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