General Information about Prescriptions and Medication Information
Abbreviations (most are from Latin) are often used by prescribers. The pharmacist then translates into plain English on the pill bottle. Some physicians are moving away from the following abbreviations and write out the prescription in plain English.
General Abbreviations
Pt. means “patient” and Rx means “script” or prescription, as in “Pt needs Rx for penicillin.” Or one could say, “Pt. needs script for penicillin.” More recently, one might see the abbreviation ERx, for “electronic prescription.”
Route of Administration
Medications can be delivered by mouth (p.o. means per os or “by mouth”), intravenously (IV), intra-muscularly (IM) or subcutaneously (subQ or SQ). Of course, virtually every outpatient Rx will be p.o. Hospitalized patients are more likely to receive IM, IV, or SQ.
Prescription Quantity and Refills
An Rx must specify the number of pills or quantity of liquid that comprises the prescription, and number of refills, if any. Usually, one sees only “#40” or similar for pills or capsules. Or one could see ml (millileters), or oz (ounces) for liquid medications.
Dose/Quantity
Medications are quantified generally in milligrams (mg). Exceptions occur, such as for Botox (units) and synthroid (micrograms, or mcg). And with liquid medication, rather than refer to mg, etc., the clinician might write gtts (drops), or the more familiar tsp (teaspoon), tbsp (tablespoon), oz (ounces).
Frequency of Administration and other Directions
This follows the “sig,” which stands for signetur, meaning “let it be labeled,” which is another way of saying “directions.” The “Q” or “q” is Latin for quague which means “once.” “B,” “T,” and “Q” stand for bis, ter, and quater which mean 2x, 3x, and 4x, respectively.
- PRN – pro re nata, meaning “as necessary.”
- QD – “every day,” or “once a day.”
- QOD – “every other day.”
- HS – (hora somni) means “at bedtime.”
- BID – twice a day or every 12 hours
- TID – three times a day or every 8 hours
- QID – four times a day, or every 6 hours but, most people take 4x a day while awake, which means first thing in the morning and at bedtime for the first and last dose of the day.
How do I Know if a New Medication Is Safe with the Ones I’m Already Taking?
This is a very important and common concern. Many people today take several medications—for blood pressure, cholesterol, prediabetes, dizziness, or other conditions. Here are some ways this can be checked:
Your doctor’s computer system
Some doctors use a computer program that lists all of your medicines and checks them for interactions. This is most often done by primary care or internal medicine doctors since they manage medications regularly.
Your pharmacy
If you always fill your prescriptions at the same pharmacy, the pharmacy computer can automatically check for interactions. Pharmacists are also trained to explain whether an interaction is serious or minor.
Your primary care doctor
If a specialist prescribes a new medication, he or she may ask you to double-check with your primary care doctor to be sure it’s safe.
Investigating yourself—with help
More tools are available now. Some people look up their medicines in reliable online sources or even use AI tools like ChatGPT for background information. But remember that only your doctor or pharmacist can give you the final word on whether the medicine is safe for you.
What if There Is an Interaction?
- Sometimes there are alternative medicines that do the same job without the interaction.
- In certain cases, a less-critical medicine (like a cholesterol-lowering drug) might be paused temporarily to see if the new one helps—though this should never be done except with expert advice, with essential medicines like those for high blood pressure.
- You can also ask your pharmacist:
- “Is this a red flag interaction (serious), or more of a yellow flag (caution but probably okay)?”
- “Does the fact that this is a low dose make it safer?”
Often, the pharmacist will reassure you that the medication is safe to try under close watch.
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