When I am proscribing a tablet to a patient should I write its name or brand name
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Here is a thorough answer based on Katzung's Basic and Clinical Pharmacology (16th Ed.) and current prescribing guidelines:
Generic Name vs. Brand Name: Which Should You Write?
The Default Rule: Use the Generic (INN) Name
Prescribing by generic name is the standard of care and is recommended by most national guidelines (NHS, WHO, AMA, FDA). The generic name is the International Nonproprietary Name (INN) - for example, diazepam instead of Valium, or atorvastatin instead of Lipitor.
Why generic prescribing is preferred:
- Cost savings - Generic drugs represent ~90% of all dispensed medications but only ~10% of total drug costs. Price differences between brand and generic can range from 2x to over 100x (Katzung's Basic and Clinical Pharmacology, p. 1040).
- Reduces errors - Each drug has one generic name but may have dozens of brand names. Generic prescribing reduces confusion during patient transfers between settings.
- Flexibility - It allows the pharmacist to dispense the best available formulation and lets insurance/formulary substitution operate normally.
- Universal - The generic name is recognized globally; brand names vary by country.
When to Prescribe by Brand Name
There are specific clinical situations where you should write the brand name:
| Situation | Example | Reason |
|---|---|---|
| Narrow therapeutic index drugs | Lithium, warfarin, phenytoin, digoxin, levothyroxine | Small bioavailability differences between manufacturers can have major clinical consequences |
| Modified-release / specific formulations | Slow-release nifedipine (Adalat LA), extended-release metoprolol | Release profiles differ significantly between brands |
| Specific delivery devices | Inhalers (Seretide vs generic fluticasone/salmeterol), insulin pens | Device technique and dose delivery vary |
| Biologics and biosimilars | Infliximab (Remicade vs Inflectra) | Biosimilars are not identical; immunogenicity and clinical data differ |
| Insulin | Always prescribe by full brand name (e.g., Lantus, not just "insulin glargine") | Different glargine products have different concentrations (U-100 vs U-300); a brand name mix-up can cause severe harm (Goldman-Cecil Medicine) |
| Patient-specific factors | Tablet appearance, taste, excipient allergies | Some patients get confused or non-adherent if the tablet looks different each refill |
The "Dispense as Written" Option
If you prescribe by brand name and want to ensure no substitution, write "Dispense as Written" (DAW) or "No Generic Substitution" on the prescription. Without this instruction, pharmacists in most jurisdictions are permitted (and sometimes required by insurance) to substitute a generic equivalent.
Quick Practical Summary
| Scenario | Write... |
|---|---|
| Routine medicines (antibiotics, antihypertensives, statins, etc.) | Generic name |
| Narrow therapeutic index drugs | Brand name + DAW |
| Modified-release formulations | Brand name |
| Insulins | Full brand name (include concentration) |
| Biologics/biosimilars | Brand name, discuss switching with patient |
Bottom line: Write the generic (INN) name for the vast majority of prescriptions. Reserve brand-name prescribing for the specific situations above where bioequivalence, formulation, or safety concerns make it clinically necessary. When in doubt about a narrow-index drug, consult your local formulary or the FDA's Orange Book for bioequivalence ratings.
Sources: Katzung's Basic and Clinical Pharmacology, 16th Ed., pp. 800, 1040-1049; Goldman-Cecil Medicine; NHS Specialist Pharmacy Service guidance
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