answered Feb 15, 2011 at 04:27PM
Generally, writing a prescription has the following components:
Medication name (brand name or generic)
formulation (tablet, capsule, liquid)
dose/strength (units in grams, mg, etc)
Followed by directions or "Sig" wich indicate the route of medication administration
Then a dispensing quantity and number of refills, if any.
The Sig line can be complex with a number of directions with regard to timing of doses, how to take the medication (with food, etc).
Here is an example for a medication for diabetes:
Metformin 500 mg tablets
Sig: Take two tablets PO BID
Disp: 120 tablets Refill: 3
Standardized abbreviations are allowed such as twice a day (BID), and by mouth (PO). However, some abbreviations are being eliminated due to medical errors associated with these. For example, QD is no longer used for "daily."