Guaifenesin/Phenylpropanolamine - how often should you take it?

Please find the dosing range below. I hope this is the information you were asking for.

Guaifenesin and phenylpropanolamine Dosing Information

Usual Adult Dose for Cough and Nasal Congestion:

- 5 mL to 10 mL (100 mg-12.5 mg/5 mL) orally every 4 hours.

- 20 mL (50 mg-6.25 mg/5 mL) orally every 4 hours.

- extended release: 1 tablet (40 mg to 50 mg phenylpropanolamine) orally every 12 hours.

Maximum is 150 mg phenylpropanolamine or 2.4 grams of guaifenesin/day.

Usual Pediatric Dose for Cough and Nasal Congestion:

6 to 12 years:

- 1 mL (50 mg-6.25mg/mL) orally every 4 hours. (Drops - Note concentration).

- 1 mL (30 mg-6.25mg/mL) orally every 4 hours. (Drops - Note concentration).

- 5mL (100 mg-6.25mg/5mL) orally every 4 hours.

Maximum is 75 mg phenylpropanolamine or 1.2 grams of guaifenesin/day.

> 12 years:

10 mL (100 mg-6.25 mg/5 mL) orally every 4 hours.

Maximum is 150 mg phenylpropanolamine or 2.4 grams of guaifenesin/day.

http://www.drugs.com/mtm/guaifenesin-and-phenylpropanolamine.html