The prescription reads for guaifenesin 400 mg PO every 4 hours as needed for congestion. Using the label below, how many mL will the nurse administer to the client? Enter a numeric value only. Answer to the nearest whole mL.

1. Determine the concentration of the guaifenesin: The label states 100 mg/5 mL. 2. Set up a proportion to find the volume (in mL) needed: 100 mg / 5 mL = 400 mg / x mL 3. Solve for x: Cross-multiply: 100x = 400 * 5 100x = 2000 x = 2000 / 100 x = 20 mL Answer: The nurse will administer 20 mL to the client.