Drug Orders: Order Templates modelling

[burke (Burke Mamlin)]

@wamz

My preferred option would be to have drug concepts that are Drug+Strength Clotrimazole 10mg/ml and leave the provider to decide the formulation, dose and duration. Option two is to have drug+strength+formulation which will require more variables to be created for each formulation

@wamz, when you say “drug concepts” do you mean “Concepts of class Drug” or entries in our drug table? I’m assuming you mean the latter.

One of the key reasons for designing the drug table around formulations (drug + strength + formulation) is because all combinations are commonly not available. For example, consider the forms of clotrimazole:

• 10 mg lozenge
• 1% cream
• 2% cream
• 1% ointment

If you were to choose drug & strength (e.g., clotrimazole 10 mg), then it wouldn’t make any sense to chose a form other than lozenge. Likewise, if you chose the strength 2%, then you shouldn’t be allowed to chose between lozenge, cream, or ointment for a form, since only cream makes sense.

Clinically, it’s okay to have additional choices based on form, since different forms are typically used for different purposes (e.g., one form may be better for hair/scalp while another form is used on skin).

@wamz

Secondly trying to tie a drug with a dose can be tricky, Paediatric doses are calculated according to body weight ,trying to define the doses is difficult and i would again let the provider select that for themselves.

You’re correct that weight-based dosing can be tricky. This is common in pediatric drugs, but not limited to pediatrics. Ideally, the system would know the strength of the drug being ordered (e.g., 10 mg/mL) and the recommended weight-based dosing (e.g., 0.5 mg/kg). When the patient’s weight is available, the system could suggest a dose (e.g., 0.5 mg/kg * 40 kg = 20 mg; 20 mg ÷ 10 mg/mL = 2 mL), but these calculations are tricky, because they need to be rounded based on dosing options (e.g., it’s not helpful to recommend 3.72 mL daily for a medication given by a 5 mL teaspoon or a 2 mL dropper). When strength, weight-based dose, weight, and dosing forms are available in structured form a computer can understand, it’s possible to calculate & recommend reasonable weight-based dosing… but it’s not a trivial problem to solve.

A reasonable near-term approach would be to allow templates to include weight-based dosing recommendations, provide weight information when available (e.g., “Weight 40 kg recorded 5 days ago”), perhaps include some tooling to help providers do the calculations (or even show the calculations as tips like “42 kg ✕ 5 mg/kg = 210 mg” so providers don’t have to manually perform the calculations and only translate those to an appropriate dose), and ideally leverage min or max daily dosage limits to help catch mistakes.

@wamz

Something like the option below would be move versatile to meet the initial prescribing need and later on tie neatly with dispensing.

I would suggest putting dispensing information (i.e., quantity & quantity units) toward the end of the instructions (i.e., don’t start with dispensing information), since the quantity can often be calculated (or entry simplified) once the instructions are known.