• Interpretation of Prescription And Medication Orders

principles of pharmacy lecture two

• interpretation of prescription and medication orders
a prescription is an order for medication issued by a physician or dentist. a prescription designates a specific medication and dosage to be prepared by a pharmacist and administered to a particular patient.
figure 1 components of a typical prescription. parts labeled are as follows:
(1) prescriber information.
(2) patient information.
(3) date prescription was written.
(4) "? " or just "rx" symbol (the superscription), meaning "take thou," "you take," or "recipe"
(5) medication prescribed (the inscription)
(6) dispensing instructions to the pharmacist (the subscription)
(7) directions to the patient (the signa)
(8) the refill directions, in which information about how many times, if authorized, a prescription can be refilled is provided.
(9) prescriber signature.
(10) drug enforcement administration (dea) registration number and/or the state registration number of the prescribing authority.

a prescription or medication order for an infant, child, or an elderly person may also include the age, weight, and/or body surface area (bsa) of the patient. an example of a prescription written for a pediatric patient is shown in next two figures. this information is sometimes necessary in calculating the appropriate medication dosage.




• the prescriptions may be written for a single component (prefabricated product) or written for more than a single component and requiring compounding.
a medication may be represented by chemical name or nonproprietary (generic) name of the substance (fig. 2) or the manufacturer s brand (trademark) name (fig1).

prescriptions requiring compounding contain the quantities of each ingredient required (fig. 3).


medications are prepared into various types of dosage forms (e.g., tablets, syrups, injections) and drug delivery systems (e.g., transdermal patches) to ensure that the medication is administered accurately and appropriately.

• hospital and other institutional medication order forms
in hospitals and other institutions, the forms are somewhat different and are referred to as medication orders. a typical medication order sheet is shown in figure 4. the orders shown in this example are typed typically, these instructions are written by the physician figure 7. in addition, other forms may be used within a hospital by specialized units.

tamper-resistant prescription pads
to prevent the unauthorized copying, modification, or counterfeiting of prescriptions, tamper-resistant prescription pads have been developed. their use is mandated for hand-written pre¬scriptions for outpatient drugs covered by medicaid. " the tamper-resistant qualities of these prescription forms is accomplished through the use of security paper, erase-resistant paper, thermo-chromatic ink ( "void" appear on photocopies).
prescription and medication order accuracy
it is the responsibility of the pharmacist to ensure that each prescription and medication order received is correct in its form and content, is appropriate for the patient being treated, and is subsequently filled, labeled, dispensed, and administered accurately. in essence, each medication should be:
• therapeutically appropriate for the patient,
• prescribed at the correct dose
• dispensed in the correct strength and dosage form,
• correctly labeled with complete instructions for the patient and
• for the patient in a hospital or other health care facility, each medication must be administered to the correct patient, at the correct time, and by the correct rate and route of administration.
labeling
the label has the name of the patient and physician the correct drug name, quantity, and strength the name or initials of the pharmacist who filled the order, and the number of refills remaining.
example:
refer to the prescription shown in figure 2 to identify any errors and/or omissions in the following prescription label.


• use of abbreviations and symbols
the use of abbreviations is common on prescriptions and medication orders. some are derived from the latin, whereas others have evolved through prescribers use of writing shortcuts. unfortunately, medication errors can result from the misuse, misinterpretation, and illegible writing of abbreviations.

abbreviations and prescription notations plays an important part in pharmaceutical calculations and thus in the accurate filling and dispensing of medication.
• examples of prescription directions to the pharmacist:
(a) m. ft. ung.
mix and make an ointment.
(b) ft. supp. no xii .
make 12 suppositories.
(c) m. ft. cap. d. t. d. no. xxiv
mix and make capsules. give 24 such doses.
- examples of prescription directions to the patient:
a- caps. i. q.i.d. p.c. et h. s.
take one (1) capsule four (4) times a day after each meal and at bedtime.
b- gtt. ii rt.eye q.d. a.m.
instill two (2) dropings in the right eye every morning.
c- tab. ii stat tab. 1 q. 6 h. 7 d.
take two (2) tablets immediately, then take one (1) tablet every 6 hours for 7 days.


• medication scheduling and patient compliance
medication scheduling may be defined as the frequency (i.e., times per day) and duration (i.e., length of treatment) of a drug s prescribed or recommended use.
some medications, because of their physical, chemical, or biological characteristics or their dosage formulations, may be taken just once daily for optimum benefit, whereas other drug products must be taken two, three, four, or more times daily for the desired effect.
frequency of medication scheduling is also influenced by the patient s physical condition and the nature and severity of the illness or condition being treated. some conditions, such as (indigestion), may require a single dose of medication for correction. other conditions, such as (a systemic infection), may require multiple daily, around-the-clock dosing for 10 days or more. long-term maintenance therapy for condi¬tions such as diabetes and high blood pressure may require daily dosing for life.

• patient compliance : with prescribed and no prescribed medications is defined as patient understanding and adherence to the directions for use. the compliant patient follows the label directions for taking the medication properly and adheres to any special instructions provided by the prescriber and/or pharmacist.
• patient noncompliance: is the failure to comply with a practitioner s or labeled direction in the self-administration of any medication. noncompliance may involve : under-dosage or over-dosage, inconsistent or sporadic dosing, incorrect duration of treatment, and drug abuse or mis-adventur¬ing with medications.





patient noncompliance factors:
patient noncompliance may result from a number of factors, including:
1- unclear or misunder¬stood directions.
2- undesired side effects of the drug that discourage use.
3- lack of patient confidence in the drug and/or prescriber.
4- discontinued use because the patient feels better or worse.
5- eco¬nomic reasons based on the cost of the medication,
6- absence of patient counseling and understand¬ing of the need for and means of compliance,
7- confusion over taking multiple medications.
patients in hospitals, nursing homes, and other inpatient settings are generally more compliant because of the efforts of health care personnel who are assigned the responsibility of issuing and administering medication on a prescribed schedule. even in these settings, however, a scheduled dose of medication may be omitted or administered incorrectly or in an untimely fashion because of human error or oversight.
- the consequences of patient noncompliance may include: worsening of the condition, the requirement of additional and perhaps more expensive and extensive treatment methods or surgical procedures, otherwise unnecessary hospitalization, and increased total health care cost.
some of the different types of problems relating to patient compliance with medication are exemplified by the following examples.
examples:
hydrochlorothiazide 50 mg no. xc
sig. tab i q am for hbp
if the prescription was filled initially on april 15, on about what date should the patient return to have the prescription refilled?

answer: 90 tablets, taken 1 per day, should last 90 days, or approximately 3 months, and the patient should return to the pharmacy on or shortly before july 15 of the same year.
r penicillin v potassium oral solution 125 mg/5 ml
disp. ml
sig. 5 ml q 6h atc x d
how many milliliters of medicine should be dispensed?
answer: 5 ml times 4 (doses per day) equals 20 ml times 10 (days) equals 200 ml.

a pharmacist may calculate a patient s percent compliance rate as follows:
% compliance rate = number of days supply of medication / number of days since last rx refill x 100
example: what is the percent compliance rate if a patient received a 30-day supply of medicine and returned in 45 days for a refill?
% compliance rate (cr)— 30 days /45 days x 100 = 66.6%, answer.
in determining the patient s actual (rather than apparent) cr, it is important to determine if the patient had available and used extra days dosage from some previous filling of the prescription.