Prescription

History of the Prescription

Prescriptions have been a method and tool used since ancient times. Latin¹ was the standard language adopted for the writing of prescriptions.

The symbol $\text{Rx}$ was used to mean prescription. Other similar symbols were also used such as $\text{Pt}$, $\text{Dx}$, $\text{Tx}$, $\text{Hx}$, $\text{Sx}$, etc., they each have their own meanings.

Prescription Drugs²

Prescription drugs are drugs that require a prescription due to its potentially harmful effects if used under no supervision of a licensed healthcare practitioner.

Health Care Practitioner’s Abbreviations

Symbol	Meaning
$\text{Pt}$	Patient
$\text{Dx}$	Diagnosis
$\text{Tx}$	Therapy
$\text{Hx}$	History
$\text{Sx}$	Symptom
$\text{Sz}$	Seizure
$\text{Fx}$	Fracture
$\text{Wt}$	Weight
$\text{LBP}$	Low back pain
$\text{CTS}$	Carpal tunnel syndrome
$\text{VS}$	Vital signs
$\text{BP}$	Blood pressure
$\text{P}$	Pulse
$\text{HR}$	Heart rate
$\text{T}$	Temperature
$\text{RR}$	Respiratory Rate

Prescription ($\text{Rx}$)³

A prescription is a written or electronic order for a particular medication for a particular patient.

Healthcare practitioners who can write prescriptions are physicians, veterinarians, and dentists.

Below is the format of a prescription:

• Heading
  • Name, address, and telephone number of the prescriber
  • Name, sex, and age of the patient
  • Date of the prescription
• Body
  • The Rx symbol
  • Name
  • Dose size or concentration (liquids) of the drug
  • Amount to be dispensed
  • Directions to the patient
• Closing
  • Prescriber’s signature
  • Refill instructions
  • Generic substitution instructions

Major Parts of Prescription

Superscription⁴

Holds the $\text{Rx}$ symbol.

Inscription⁵

The medication prescribed.

Subscription⁶

The dispensing instructions to the pharmacists.

Signa⁷

Direction given or instruction to the patient to be relayed by the pharmacist

Parts of a Prescription Order

• Prescriber information and signature
• Patient information
• Date Rx was written
• Superscription
• Signa
• Special instructions (optional)
• Additional info for GP:
• License number
• PTR No.

Heading

• Patient Name and Address
  • Full first and last name; Middle initial may be helpful
  • DOB – not required, but will be helpful in further identifying the correct patient to prevent medication errors
• Other data pertinent to the patient;
  • “A” on a prescription means “Adult”
  • “O” on a prescription means script/prescription for oral contraceptive
  • “J” on a prescription means “under 16 years”
  • “Y” on a prescription means “under 6 years of age”
• Practitioner’s name, address, and phone number
  • Validates prescription
  • Provides contact information to clarify any questions
• Date
  • Date the Rx is issued or written
  • Allows the determination of the life of the Rx to validate refills
  • Ensures continual patient supervision
  • Promotions patient follow-up

Body

• Selecting the drug
  • Medication allergies
  • Availability
  • Cost
• Name of the drug
  • Multiple drugs per Rx can add to confusion
  • KEEP IT SIMPLE
  • CAUTION for Sound Alike-Look Alike Drug (SALAD) names, due to
    • Massive number of new drug releases
    • Massive number of reformulations
    • Drug marketing strategy
      • Build on established names
      • New combination drugs that use converged (combined) names
  • AVOID THE USE OF
    • Abbreviations
      • Many drugs are identified with abbreviations, e.g. HCT for hydrochlorothiazide, MSO4 for morphine sulfate, etc.
      • Attempts to standardize abbreviations have been unsuccessful
• Dose size or concentration (liquids) of the drug/ Strength of the drug
  • Be familiar with drugs and their various dosing strengths and dosage forms
  • When in doubt, use references
  • Weight-based dosing: always convert patient weight to correct units (kg)
  • Liquid medications
    • One product may be available in many concentrations
    • Be familiar with various product concentrations
    • Indicate BOTH concentration and dose of medication
    • Example: “Cephalexin suspension 125 mg/5 ml 1 teaspoon every 8 h”
  • In using decimal points
    • Avoid trailing zeros, e.g. 5mg vs 5.0mg can be mistaken for 50mg
    • Always use leading zeros, e.g. 0.8ml vs .8ml can be mistaken for 8ml
  • Amount (quantity) of drug to be dispensed
    • Prescribe only necessary quantity
  • Write specific quantities rather than time period, e.g., “dispense #30” vs “dispense for 1 month”
  • Calculate quantity = frequency per day x treatment days
  • Writing out “dispense x” is helpful
• Directions for use to the patient
  • Write out in full English or use Latin abbreviations
  • Latin abbreviations – more convenient, more potential for mistakes
    • Avoid dangerous abbreviations
  • Provide clear and specific directions
  • Directions should be clearly indicated, e.g.:
    • Atenolol 100mg once daily
    • Amoxicillin 250mg tds (ter die sumendus)
  • Tell the patient what you mean by these
  • Determine preference for brand or generic product
    • Brand vs generic. Is brand always better?
    • If practitioner prefers brand, must indicate in print, with written “DO NOT SUBSTITUTE”
  • Indication
    • Encouraged, seldom practiced
    • Helps confirm appropriateness of med
    • Reminds patient of drug’s purpose
    • Facilitates communication between health providers

Closing

• Refills
  • To avoid interrupting maintenance therapy, practitioners can authorize refills on a written prescription
  • Refills authorized are valid only for life of the prescription – 1 year
• For CONTROLLED SUBSTANCES
  • A prescription drug whose use and distribution is tightly controlled because of its abuse potential or risk
  • Regulation is more strict

Rules for Writing Quantities of Drugs

• Quantities of 1 gram or more should be written in grams, e.g., write 2g
• Quantities less than 1 gram but more than 1 milligram should be written in milligrams, e.g., write 100mg not 0.1g
• Quantities less than 1 milligram should be written in micro/nanogramas appropriate
• DO NOT abbreviate micro/nanograms since then can lead to prescribing errors, e.g., write 100 micrograms, not 0.1mg, not 100mcg, nor 100ug
• Use ml or mL for milliliters
• For some drugs, a maximum dose may need to be stated, e.g., ergotamine in migraine and colchicine in gout. For example, “Ergotamine 1mg at onset of attack and repeat every 30 minutes if necessary. Do not take more than 6mh in one day or more than 12mg in one week.

Prescription of Controlled Drugs

1. Completely written in the prescriber’s handwriting in ink
2. Signed and dated
3. Carry the prescriber’s address
4. Carry the name and address of the patient
5. State the form of the drug
6. State the total quantity of the drug or the number of dose units to be disposed in both words and figures
7. State the exact size of each dose in both words and figure

To Maximize Safety

• writing should be legible
• words should be spaced out from numbers to avoid confusion
• Medication orders should be complete
• Abbreviations should be avoided
• When in doubt, ask to verify

Footnotes

1. Latin was the language adopted for the writing of prescriptions. ↩

2. Prescription drugs are potentially harmful drugs that require the prescription from a licensed healthcare practitioner. ↩

3. A Prescription is a written or electronic order for a particular drug for a specific patient. The symbol Rx means receive in Latin. ↩

4. Superscription holds the Rx symbol. ↩

5. Inscription is the medication prescribed. ↩

6. Subscription contains dispensing information to the pharmacists. ↩

7. Signa contains the direction to be relayed to the patient by the pharmacists. ↩