While using clinical expertise to determine if a dose is appropriate or not, you may come across some high doses which are perfectly reasonable. Although it may scare you, it is always helpful to speak with the patient, learn more about the indication and provide counselling.
Here are common examples of “high” but clinically appropriate doses.
1) Amoxicillin: Especially for pneumonia and otitis media, some prescribers want to prescribe high-dose amoxicillin to overcome Strep pneumoniae resistance. At 75 to 90 mg/kg/day (even up to 100 mg/kg/day), this dose can cause upset stomach and diarrhea.
2) Domperidone: Used for lactation purposes, breastfeeding experts recommend doses above the 30 mg/day limit imposed by Health Canada. This limit is due to increased QT prolongation and cardiac concerns. For breastfeeding, as long as the patient has no risk factors (cardiac history, elderly (>60 years old), electrolyte changes, other QT drugs, CYP3A4 inhibitors), then it may be acceptable to see 30 to 40 mg three times daily.
3) Symbicort: With a change in asthma guidelines recently (see the 2020 GINA report), more prescribers will be giving Symbicort 2 puffs four times daily as needed (max 8 puffs per day). Symbicort combines the advantages of a reliever and controller into one device.
4) Prednisone: Have you ever seen 1250 mg daily x 3 days? Usually the dose is 50 mg once daily for inflammatory conditions, but this dose is extremely high. A patient with a multiple sclerosis flare may need a very high dose to control their condition. If a patient is using 50 mg tablets, this means they will take 25 tablets daily (that’s a lot!). Make sure to counsel on an upset stomach and to take with food!