Issue: February 1997
Disclosures: Christensen has no direct financial interest in products mentioned in this article, nor is he a paid consultant for any companies mentioned.
February 01, 1997
6 min read

How to write prescriptions clearly and concisely

Issue: February 1997
Disclosures: Christensen has no direct financial interest in products mentioned in this article, nor is he a paid consultant for any companies mentioned.
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With the recent changes in optometric state laws, optometrists now have the privilege and responsibility for writing prescriptions. A written prescription is a legal document that should be prepared with care. While there are some variations from state to state, the prescription basically has 10 parts that will be discussed in this article. Use this information as a guide, but make sure you know the requirements in your own state. Also, be aware of the different requirements for prescriptions for controlled substances vs. noncontrolled substances.

Parts of a prescription

Prescriber information: The doctor's name, address and phone number should be clearly written (or preprinted) on the top of the prescription form. Some states require the doctor's state license number to be on the form. It is not recommended that you preprint your Drug Enforcement Administration (DEA) number on the prescription pad. It becomes too easy for drug abusers to lift a few prescription forms for illicit use if that number is easily available. The DEA number is not required on noncontrolled prescriptions; however, many pharmacies may request the DEA number with a prescription to help when filing the patient's medication insurance claims.

For those who do not use their DEA number: Prescriptions are often counted by the DEA number. If that number is not used on prescriptions written by optometrists, the count will not reflect an accurate number of prescriptions coming from our profession. This will affect the support optometry receives from pharmaceutical companies in terms of service, educational program support and involvement in pharmaceutical clinical trials.

Patient information: This portion of the prescription should include at least the first and last name of the patient and the age of the patient. Many names such as "Smith" and "Jones" should include the complete name and address to help distinguish patients with similar names. An address is required on schedule II controlled drugs and should be included on prescriptions for any controlled substance. When the exact age is unavailable the word "adult" may be used in the age slot. Children and the elderly may need the weight listed when oral medications are prescribed.

Date prescribed: The date is part of the legal document confirming when the prescription was written. Pharmacists are often presented prescriptions with dates that are well past the prescribing date. Some patients elect to save prescriptions for future use. This often includes antihistamines and antibiotics that may not be indicated or are even dangerous for the patient's present condition.

Superscription: This is the Rx symbol on the prescription form that designates the written document to be a prescription. Rx is an abbreviation for a Latin phrase that means "take thou."

Inscription: An inscription includes the drug name, concentration and type of preparation. Drug names should not be abbreviated and correct spelling is important to assure that the correct medication is dispensed. Maxitrol (neomycin and polymyxin b sulfates and dexamethasone, Alcon) and Tobra Dex (tobramycin and dexamethasone, Alcon) are examples of drugs that are prepared in ointment (ung) or drop (gt) form. Cortisporin (neomycin and polymyxin B sulfates, bacitracin zinc and hydrocortisone, Glaxo Wellcome) comes in ophthalmic and otic (ear drops) preparations. Specify which preparation you wish the patient to use.

Drug names can be written using the chemical name, such as ciprofloxacin 0.3% (Ciloxan, Alcon) or the proprietary form that requests a specific brand name drug. This preparation is still under patent, so if you use either name the pharmacy will provide the product manufactured by Alcon.

Tobramycin has recently come off patent. If you prescribe "Tobrex" the patient should receive the drug manufactured by Alcon unless you check the box on the prescription stating generics are acceptable. If you write "tobramycin," the patient will likely receive the generic form of the drug.

Homatropine and pilocarpine come in different concentrations. It is good practice to always specify the concentration, even if the drug comes in only one concentration. That drug may come in other concentrations in the future. Concentration and preparation form should be written just to the right of the drug name. Use the metric system of weights and measures.

To avoid misinterpretation of the preparation strength, follow this standard in writing percentages: If the percent is less than one, always precede the decimal with a zero, such as 0.1% or 0.05%. If the percent is greater than one, with no fraction, do not use a zero after the decimal, such as 1%. Writing 1.0% could easily be misread as 10%.


The doctor's instructions to the pharmacist, Sig, should be as specific as possible to ensure patient compliance and proper use of medication.

Signatura (Sig): These are the doctor's instructions to the pharmacist indicating how the patient should use the medication. Latin or English abbreviations are used to provide specific instructions translated by the pharmacist for patient use. Typical instructions on the prescription would follow in this order:

  • 2 gtt q2h OD for 3 days These instructions as used on a prescription for Ciloxan would be interpreted as follows: two drops every 2 hours instilled in the right eye for 3 days.
  • 1 tab po BID for 14 days These instructions as used on a prescription for doxycycline would be interpreted as follows: one tablet by mouth two times per day for 14 days.
  • 1 gt QID OU for 7 days, then BID for 14 days, for itchy eyes SHAKE These instructions as used on a prescription for Livostin (levocabastine HCl, Ciba Vision Ophthalmics) would be interpreted as follows: one drop of Livostin four times per day in each eye for 7 days and then decreased to two times per day for 14 days, for itchy eyes caused by allergies; shake drops before use.

These instructions should be as specific as possible. Poor instructions given in the office and on the prescription lead to poor compliance and often improper use of the medication. It is appropriate to write what the medication is being prescribed for in the signatura to let the patient know the indications for the medication. Phrases such as "for eye pain" or "for itchy eyes" will help ensure that the medication is used appropriately.

Refill data: Provide the number of refills the patient should need to complete the cycle of drug treatment. Most antibiotic and steroid prescriptions need no refills or one refill. Glaucoma medications usually have three refills, which allows the patient enough medication for 3 to 6 months, depending on the size of the bottles dispensed. Schedule II controlled substances have no refills. Schedule III through V controlled substances can have five refills or can be refilled for a maximum of 6 months, whichever comes first. In eye care there is seldom a reason to have more than one refill on these controlled drugs.

Substitution permitted: Marking "Yes" allows the pharmacist to substitute a generic form of the medication prescribed. Some health plans request that the generic drug be used to save money. When writing the drug names remember that generic names are not capitalized and brand names are capitalized: Pred Forte (Allergan) or prednisolone acetate 1%.

Signature: Your signature and degree finalize the legal document. A signature stamp can be used for noncontrolled substances. Prescriptions for controlled drugs require a handwritten signature and DEA number.

Subscription (Disp): Historically, this was an instruction to the pharmacist to compound medications. This could include, for example, instructions regarding the fortification of tobramycin for treating a corneal ulcer. Today, most medications are pre-compounded preparations. Subscription now indicates the quantity of medication (number of capsules or tablets) or the size of the bottle to be dispensed (5 mL, 10 mL, 15 mL).

Points to remember

  • Keep good records of medications prescribed, dates written, length of treatment, concentration of medication and your diagnosis of the condition.
  • Explain specifically to the patient how to use the medication and why it should be used.
  • When possible, explain dosage, diagnosis and the reason for the treatment to the available care giver of the patient (spouse, parent, child, friend, nurse).
  • Give written instructions to the patient in the office when the dosage schedule is complicated. When multiple medications are prescribed and tapering of dosage is needed, written instructions are especially important to achieve compliance.
  • Illiteracy is the forgotten reason for noncompliance. If you suspect the patient cannot read or may not be able to understand written instructions, check for understanding by having the patient repeat the instructions verbally after you have explained how to use the medication. If possible, explain the dosage and treatment plan to a family member.

A prescription written precisely and completely finalizes the plan for improvement of the health and welfare of your patient's eyes. Learning the system for writing prescriptions requires actually writing them and reviewing the above guidelines to be sure the instructions and format are correct.

Use your resources to assure accuracy. When unsure, check your drug reference literature on how to write a prescription, especially for an infrequently used medication. Your pharmacist is a valuable source of information; don't be intimidated by calling and asking his or her opinion.

For Your Information:

Bobby Christensen, OD, is in private practice in Midwest City, Okla. He lectures widely on therapeutic pharmaceutical agents. He can be contacted at Heritage Park Medical Center, 6912 E. Reno, Suite 101, Midwest City, OK 73110; (405) 732-2277; fax: (405) 737-4776.