Guaifenesin Dosing for a 31.3 kg Child
For a child weighing 31.3 kg, administer guaifenesin 200-400 mg orally every 4 hours, not exceeding 2,400 mg per day (6 doses), using the immediate-release formulation. 1
Weight-Based Dosing Considerations
The standard adult dosing range of 200-400 mg every 4 hours (up to 6 times daily) applies to children weighing over 12 kg, as guaifenesin dosing in pediatric patients typically follows adult guidelines once children reach school age and adequate weight. 1
At 31.3 kg, this child falls well within the weight range where adult dosing protocols are appropriate, as children aged 2 years and older are pharmacologically similar to adults and differ primarily in size rather than drug metabolism. 2
Start with 200 mg every 4 hours and titrate upward to 400 mg every 4 hours if symptom relief is inadequate, as the dosing range allows flexible titration to optimize therapeutic plasma concentrations. 1
Dosing Schedule and Formulation
Immediate-release guaifenesin requires dosing every 4 hours to maintain therapeutic effect due to the drug's short half-life, with a maximum of 6 doses in 24 hours. 1, 3
Extended-release formulations (600 mg or 1,200 mg every 12 hours) are available and provide convenience with twice-daily dosing, though these are typically reserved for older children and adults who can swallow larger tablets. 3
For a 31.3 kg child, if using extended-release formulation, the dose would be 600 mg every 12 hours, which is bioequivalent to 200 mg immediate-release every 4 hours. 3
Safety Profile and Monitoring
Guaifenesin has a well-established and favorable safety profile in pediatric populations, with documented side effects generally being mild. 1
The maximum daily dose of 2,400 mg should not be exceeded, as higher doses have been associated with central nervous system depression in overdose situations. 4
Food does not significantly affect absorption of extended-release formulations, though it may delay time to maximum concentration without affecting overall exposure. 3
Clinical Context
Guaifenesin is indicated for relief of wet cough and chest congestion in acute upper respiratory tract infections and chronic bronchitis, acting by loosening mucus and making coughs more productive. 1
Multiple daily doses are necessary with immediate-release formulations to maintain 24-hour therapeutic effect, making adherence an important consideration. 1