Prescriptions should be written after a diagnosis or a health problem has been identified. The prescription will present the necessary drugs and measures sufficient to heal or improve the state of the patient. The prescription must then contain all the necessary information clearly written.

Known roman numerals usually written in prescriptions to represent dosage are:

i, ii, iii, representing one, two and three.

It is better to state dosage in terms of strength (e.g. 500 mg) than number of tablets. This is because some drug products are available in different strengths (e.g. diazepam 5 mg and 10 mg).

Avoid the use of decimal points when stating the strength of a drug-500 mg is preferred to.5 gm and 250 micrograms is preferred to.25 mg. This is because if the decimal point does not appear clearly, a wrong strength of drug may be dispensed as 25 mg instead of.25 mg. If a decimal point is not avoidable, then precede it with a 0 such as 0.25.

Too many abbreviations, illegible writing or ambiguous instructions can lead to errors in dispensing. It is therefore recommended that prescriptions should be unambiguous and written legibly.

Example: Rx

Paracetamol 500 mg tabs ii tds x 3 days

The prescription is clear as it states:

• The dosage form of the paracetamol - tablets,
• The strength of the paracetamol tablets - 500 mg per tablet,
• The number of days for which the paracetamol tablets have been prescribed,
• The number of times the tablets should be taken each day,
• The number of paracetamol tablets to be taken each time.