Caution codes, drug: Abbreviations on medications that indicate caution. While not a part of the historical heritage of ancient prescription abbreviations, drug caution codes provide very valuable warnings.

They include both universal and specific caution codes:

• Universal caution codes:
  • D = drowsiness
  • H = habitforming
  • I = interaction
  • X = SOS (contains a substance such as acetaminophen that could cause problems -- consult your pharmacist)
• Special caution codes
  • ASA = contains acetylsalicylic acid (aspirin)
  • C = caution
  • G = glaucoma
  • S = diabetes

These special caution codes are intended to be warnings for patients with specific medical conditions. For example, a person with hypertension might see the generic "C" code on a prescription bottle or vial if the medication might raise his or her blood pressure.

If you see one of the universal or special caution codes on a prescription, talk to your pharmacist about it before using the medicine.

In the United States and some other countries, a system of stickers with pictographs is also used to warn of side effects such as drowsiness.