Pharmacy Calculations for PTCB, ExCPT

Basic Math Skills

• Fractions, decimals, and percentages
• Ratios, strengths and proportions
• Unit conversions (e.g., grams to milligrams, liters to milliliters)
• Pharmacy Abbreviations

Day Supply Calculations

• Solid Dosage Forms (Tablets, Capsules, Lozenges)
• Liquid Medications (Syrups, Suspensions, Solutions)
• Topical Medications (Creams, Ointments, Gels)
• Inhalers (MDIs, DPIs, Nebulizer Solutions)
• Eye/Ear Drops
• Insulin (Vials, Pens, Cartridges)
• Transdermal Patch
• Controlled Substances & DEA Limits

Quantity Calculations

1. Quantity for Solid Dosage Forms (Tablets, Capsules)
2. Quantity for Liquid Medications (Syrups, Suspensions)
3. Quantity for Topical Medications (Creams, Ointments, Gels)
4. Quantity for Inhalers (MDIs, DPIs, Nebulizer Solutions)
5. Quantity for Eye/Ear Drops
6. Quantity for Insulin (Vials, Pens, Cartridges)
7. Quantity for Transdermal Patches
8. Quantity for Controlled Substances (DEA Limits)

Medication Dosing Calculations

• Basic Formula Method
• Ratio and Proportion Method
• Dimensional Analysis (Unit Conversion)
• Weight-Based Dosage (mg/kg/day)
• IV Flow Rate Calculations / (Drip Rate)
• Body Surface Area (BSA) Method
• Clark’s Rule (Pediatric Dose)
• Fried’s Rule (Infants under 1 year)
• Young’s Rule (Children 1-12 years)

Conversions

• Metric conversions (mg ↔ g, mL ↔ L, etc.)
• Household to metric (teaspoon ↔ mL, ounce ↔ mL, pound ↔ kg)
• Apothecary conversions (grain ↔ mg, dram ↔ mL)

3. Percentage Calculations

• % strength w/v, w/w, v/v
• Dilution/concentration problems using:
  • C₁V₁ = C₂V₂

Compounding Calculations

• Alligation (used to mix two concentrations)
• Powder volume and reconstitution
• Calculating ingredients for creams, ointments, and suspensions

Business Math

• Markup, profit margin, cost calculations
• Discounts and insurance reimbursement

 Temperature Conversions

• °C ↔ °F:
• °F = (°C × 1.8) + 32
• °C = (°F – 32) ÷ 1.8

Roman Numerals

Apothecary System Calculations

• Apothecary Weight Units
• Apothecary Volume Units

Legal & Ethical Calculations

• DEA number verification (not a math problem but involves checksum validation)
• Controlled substance waste calculations