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📊 Days of Supply Reference

Comprehensive guide for calculating days of supply for all medication types

📋 General Rules & Overview

Rounding Rule

Always round DOWN to the previous whole number if the calculated DOS contains a decimal.

Example: 4.9 days → round down to 4 days

Key Guidelines

  • In-Use Guidelines: Follow manufacturer in-use (opened by patient) guidelines when calculating DOS for products with shortened expiration after opening
  • Plan Limits: If a third party plan rejects with "Plan Limits Exceeded," follow Unit of Use procedures or dispense less than prescribed quantity
  • Ambiguous Directions: Contact prescriber if directions are unclear or open to multiple interpretations
  • Insulin Prescriptions: Must have clear frequency with max daily dose to mitigate audit/chargeback risk
💊 Tablets, Capsules, Granules, Liquids, Suppositories
DOS = Total Quantity Dispensed ÷ Daily Dose
Example 1: Metformin 500mg tablets, "Take 1 tablet by mouth twice daily"
Dispense #60 tablets
60 tablets ÷ 2 tablets/day = 30 DOS
Example 2: Carafate oral suspension, "Take 10 mL by mouth four times daily"
Dispense 1200 mL
1200 mL ÷ 40 mL/day = 30 DOS
Example 3: Promethazine 25mg suppositories, "Insert 1 suppository rectally 2-3 times daily as needed"
Dispense #20
20 suppositories ÷ 3 (maximum per day) = 6.6 → 6 DOS
💨 Sprays and Inhalers
DOS = Total Doses in Container ÷ Daily Dose
Example 1: ProAir Inhaler (200 puffs), "Inhale 2 puffs by mouth twice daily as needed"
2 puffs × 2 times/day = 4 puffs/day
200 puffs ÷ 4 puffs/day = 50 DOS
Example 2: Fluticasone Nasal Spray (120 doses), "Spray once in each nostril twice daily"
(1 spray × 2 nostrils) × 2 times/day = 4 sprays/day
120 doses ÷ 4 sprays/day = 30 DOS
👁️ Eye and Ear Drops
DOS = (mL Dispensed × 20 drops/mL) ÷ Drops Used Daily
Note: Standard conversion is 20 drops per mL for most solutions and suspensions. Some medications have different drop conversions - IC+ will automatically calculate these.
Volume # Drops (at 20/mL)
1 mL20 drops
5 mL100 drops
10 mL200 drops
15 mL300 drops
Example: Prednisolone Ophthalmic Suspension 5 mL, "Instill 2 drops in both eyes twice daily"
2 drops × 2 eyes × 2 times/day = 8 drops/day
5 mL × 20 drops/mL = 100 drops
100 drops ÷ 8 drops/day = 12.5 → 12 DOS
Important: For single-use vials (e.g., Restasis), use the number of vials per package to calculate DOS, not the drops/mL conversion.

📋 Ophthalmic Medication Reference

Comprehensive list of common ophthalmic medications with drops per mL conversions and package information.

Medication Name NDC Drops/mL Package Size & Total Drops
Beta Blockers
Timolol 0.25% GF Ophth Soln 82260-0818-25 29 5mL = 145 drops
Timolol 0.5% GF Opth Soln 24208-0819-05 29 5mL = 145 drops
Timolol Maleate 0.5% Opht Soln 82260-0813-05 32 5mL = 160 drops
Timoptic 0.25% Opth Soln 24208-0812-05 32 5mL = 160 drops
Timoptic 0.5% Ophth Soln 24208-0813-05, 24208-0813-10 32 5mL = 160 drops, 10mL = 320 drops
Timoptic-XE 0.25% Ophth Sol 24208-0814-25 29 5mL = 145 drops
Levobunolol 0.5% Opth Soln 24208-0505-05 32 5mL = 160 drops
Istalol 0.5% Ophth Solution 24208-0004-01, 24208-0004-03 32 2.5mL = 80 drops, 5mL = 160 drops
Prostaglandin Analogs
Lumigan® 0.01% Ophth Soln 00023-3205-03, 00023-3205-05, 00023-3205-08 24 2.5mL = 60 drops, 5mL = 120 drops, 7.5mL = 180 drops
Xalatan 0.005% Ophth Soln® 00013-8303-04 33 2.5mL = 82 drops
Latanoprost 0.005% Ophth Soln (Bausch & Lomb) 24208-0463-25 36 2.5mL = 90 drops
Latanoprost 0.005% Ophth Soln (Greenstone) 59762-0333-02 20 2.5mL = 50 drops
Latanoprost 0.005% Ophth Soln (Sandoz) 61314-0547-01 36 2.5mL = 90 drops
Latanoprost 0.005% Ophth Soln (Somerset) 70069-0421-01, 70069-0421-03 36 2.5mL = 90 drops, 7.5mL = 270 drops
Vyzulta 0.024% Ophth Soln¹ 24208-0504-02, 24208-0504-05 32 2.5mL = 80 drops, 5mL = 160 drops
Alpha Agonists
Brimonidine 0.2% Ophth Soln 24208-0411-05, 24208-0411-10, 24208-0411-15 30 5mL = 150 drops, 10mL = 300 drops, 15mL = 450 drops
Combination Products
Dorzolamide-Timolol Ophth Soln 24208-0486-10 28 10mL = 280 drops
Carbonic Anhydrase Inhibitors
Dorzolamide 2% Ophth Soln 24208-0485-10 28 10mL = 280 drops
Corticosteroids
Lotemax 0.5% Ophthalmic Susp 24208-0299-05, 24208-0299-10, 24208-0299-15 31 5mL = 155 drops, 10mL = 310 drops, 15mL = 465 drops
Lotemax 0.5% Opth Gel Drops 24208-0503-07 25 5GM = 125 drops
Lotemax SM® 0.38% Gel Drops 24208-0507-07 N/A 5gm = 131 drops
Loteprednol 0.2% Ophth Susp 82260-0361-05 31 5mL = 155 drops
Loteprednol 0.5% Opth Gel Drops 24208-0508-01 25 5GM = 125 drops
Alrex 0.2% Ophthalmic Susp 24208-0353-05, 24208-0353-10 32 5mL = 160 drops, 10mL = 320 drops
Dexamethasone 0.1% Ophth Soln 24208-0720-02 31 5mL = 155 drops
Antihistamines
Bepotastine 1.5% Opth Drops 24208-0630-05, 24208-0630-10 33 5mL = 165 drops, 10mL = 330 drops
Bepreve 1.5% Opth Drops 24208-0629-02, 24208-0629-01 33 5mL = 165 drops, 10mL = 330 drops
Antibiotics & Antivirals
Besivance 0.6% Opth Susp 24208-0446-05 31 5mL = 155 drops
Zirgan 0.15% Ophth Gel 24208-0535-35 27 5GM = 135 drops
Zylet Ophthalmic Suspension 24208-0358-05, 24208-0358-10 32 5mL = 160 drops, 10mL = 320 drops
NSAIDs
Bromfenac 0.07% Opth Solution 82260-0602-03 21 3mL = 63 drops
Diclofenac Sod 0.1% Ophth Soln 24208-0457-05 28 5mL = 140 drops
Prolensa 0.07% Opth Solution 24208-0602-03 19 3mL = 57 drops
Mydriatics/Cycloplegics
Atropine Sulf 1% Oph Soln 82260-0001-01 31 10mL = 310 drops
Cyclopentolate 1% Ophth Sol 24208-0735-01, 24208-0735-06 31 2mL = 62 drops, 15mL = 465 drops
Specialty & Other
Miebo 1.3gm/mL Opth Sol² 24208-0377-05 90 3mL = 272 drops
Vevye 0.1% Ophth Soln³ 82667-0900-02 100 2mL = 200 drops
📋 Footnotes:
¹ Vyzulta: Latanoprostene bunod ophthalmic solution
² Miebo: Perfluorohexyloctane ophthalmic solution - unique viscosity requires different drop calculation
³ Vevye: Cyclosporine ophthalmic solution 0.1% - high concentration formulation

⚠️ Important Notes:
• Different manufacturers may have different drops/mL for the same generic medication
• Always verify NDC to ensure accurate drop calculation
• Gel formulations typically have fewer drops per gram than suspensions
• These values are for multidose bottles; single-use vials are calculated per unit
🧴 Topical Medications

Common Topical DOS Values

Most topicals have pre-populated DOS values in IC+. Always use default DOS unless otherwise specified by manufacturer or prescriber.

Package Size DOS
Up to 29 grams7 days
30-44 grams15 days
45-59 grams20 days
60-99 grams25 days
100 grams or larger30 days

Specific Medications

  • Bactroban 22g: 10 days
  • Duac Gel 45g: 30 days
  • Estrace Cream 42.5g: 90 days
  • Voltaren Gel 100g: 7 days
🩹 Transdermal Patches
DOS = Number of Patches × Frequency of Application (in days)
Example 1: Duragesic 50 mcg patches, "Apply one patch every 72 hours"
Dispense #10 patches
10 patches × 3 days = 30 DOS
Example 2: Climara patches, "Apply one patch weekly"
Dispense #4 patches
4 patches × 7 days = 28 DOS
💉 Multi-Dose Insulin Vials
DOS = (Total mL × Concentration) ÷ Units Injected Daily
U-100 Insulin: 100 units/mL (most common)
U-200 Insulin: 200 units/mL
U-300 Insulin: 300 units/mL
U-500 Insulin: 500 units/mL
Example: Humulin 70-30 insulin (10 mL), "Inject 20 units subcutaneously three times daily"
Dispense #2 vials (20 mL total)
20 mL × 100 units/mL = 2000 units
20 units × 3 times/day = 60 units/day
2000 units ÷ 60 units/day = 33.3 → 33 DOS
Important: Always follow manufacturer in-use (opened) guidelines. Example: Lantus vials have a 28-day in-use limit, even if calculated DOS is higher.
🖊️ Multi-Dose Insulin Pens

Calculation Steps

  1. Calculate Total Units per Day:
    (Prescribed units per dose + Priming units) × Doses per day = Total units/day
  2. Calculate Days per Pen:
    Units per pen ÷ Total units/day = Days per pen
  3. Calculate Pens to Dispense:
    Days prescribed ÷ Days per pen = Number of pens
  4. Calculate DOS:
    (Pens dispensed × Units per pen) ÷ Total units/day = DOS
Critical: Insulin pens require priming before each injection. Standard priming is 2 units per dose. This waste must be included in DOS calculations.
Example: Novolog FlexPen (15 mL box = 5 pens × 3 mL = 1500 units)
"Inject 20 units subcutaneously three times daily with meals"

Step 1: Total units/day
(20 units + 2 priming) × 3 = 66 units/day

Step 2: Days per pen
300 units/pen ÷ 66 units/day = 4.5 days/pen

Step 3: DOS for 1 box
4.5 days/pen × 5 pens = 22.5 → 22 DOS
In-Use Guidelines: Follow manufacturer guidelines (typically 28 days max after opening). If calculated DOS exceeds in-use limit, annotate prescription and add "discard after X days" to directions.
💊 Ready to Use Injectables (Wegovy, Ozempic, Trulicity, etc.)

Single-Use Pens

DOS = (Pens per box × Days between doses)
Example: Wegovy 0.25mg (4 pens per box)
"Inject 0.25mg subcutaneously once a week"
1 pen × 7 days × 4 weeks = 28 DOS per box

Multi-Use Pens (Ozempic)

Calculate based on mL per dose and total mL in pen.

Maintenance Dose Example: Ozempic 2mg/3mL pen
"Inject 0.5mg subcutaneously once a week"
0.5mg = 0.75mL per dose
3mL ÷ 0.75mL = 4 doses
4 doses × 7 days = 28 DOS
Initiation vs. Maintenance: If prescription has both initiation/starter dose and maintenance dose, it CANNOT be refilled. Contact prescriber for separate prescriptions.
📱 Continuous Glucose Monitors & Insulin Pumps

CGM Devices

  • Dexcom G6 Transmitter: 90 DOS
  • Dexcom G6 Sensor: Apply 1 sensor every 10 days → 3 sensors = 30 DOS
  • FreeStyle Libre 3 Plus: Apply 1 sensor every 15 days → 2 sensors = 30 DOS

Omnipod

DOS = Number of PODs × Frequency Pod is Changed
Example: Omnipod 5 Pods, "Change pod every 3 days"
Dispense #45 pods
45 pods × 3 days/pod = 135 → typically dispensed as 90 DOS
🩹 Santyl (Collagenase) Ointment
Special Instructions: Use the Santyl Dosage Calculator to determine correct quantity and DOS based on wound width, length, and duration of therapy.

Wound Size Estimates

  • Small wound (<2 sq in): ~0.25g per application (¼ inch ribbon)
  • Medium wound (2-4 sq in): ~0.5g per application (½ inch ribbon)
  • Large wound (>4 sq in): ~1.0g per application (1 inch ribbon)
Example: Wound measures 1.2 × 1.2 cm, apply daily for 30 days
Santyl Calculator: 8 grams needed for 30 days
Dispense: 1 tube (30g)
30g tube ÷ 8g needed = 3.75 months
DOS = 90 days
💉 Multi-Dose Injectable Vials

General Formula

Step 1: (mLs per injection × Frequency per week) = Total mL/week
Step 2: (Total mL in vial ÷ Total mL/week) × 7 days = DOS
28-Day Rule: If MDV DOS exceeds 28 days, switch to single-dose vials (SDV) if available. If SDV not available, annotate prescription and add "Discard Remainder after 28 days" to directions.
Testosterone Example: Testosterone Cypionate 200mg/mL, 10 mL vial
"Inject 0.5mL IM twice weekly"

Step 1: mL per week
0.5mL × 2 = 1mL/week

Step 2: Calculate DOS
(10mL ÷ 1mL/week) × 7 days = 70 DOS

Problem: Exceeds 28-day limit!
Solution: Switch to 1mL SDV → Dispense 8mL for 28 DOS
🧪 Reconstitutable Medications
DOS = Total mL Dispensed ÷ Daily Dose (mL)
Special Rule: If prescriber indicates duration (e.g., "for 10 days") and not all quantity will be used, add "Discard Remainder" to directions and use prescriber's indicated duration as DOS.
Example 1: Amoxicillin 400mg/5mL suspension
"Take 5mL by mouth BID for 10 days"
Dispense 100mL
100mL ÷ 10mL/day = 10 DOS
Example 2: Cefdinir 250mg/5mL suspension
"Give 5mL by mouth daily for 10 days"
Dispense 60mL
60mL ÷ 5mL/day = 12 DOS
→ Update to 10 DOS with "Discard Remainder" added