Patient-Controlled
Analgesia (PCA)
Dosage Calculations
Comprehensive
Guide for Nursing
Students
�WHAT IS PCA?
Patient-Controlled Analgesia (PCA) is a method of pain management that allows
patients to self-administer predetermined doses of analgesic medication (typically
opioids) using a programmable pump. The patient controls the timing of medication
delivery by pressing a button, but the dose and frequency are limited by safety
parameters programmed by the healthcare provider.
,�KEY PCA TERMINOLOGY
Term Definition Typical Values
Demand The amount of medication delivered when the 0.5-2 mg morphine,
Dose patient presses the button 10-20 mcg fentanyl
The minimum time between doses; pump will
Lockout
not deliver if button is pressed during this 5-15 minutes
Interval
period
Continuous infusion of medication (background
Basal Rate 0.5-2 mg/hr morphine
rate)
Loading Initial bolus dose given to establish therapeutic
2-5 mg morphine IV
Dose effect before PCA started
1-Hour Maximum total dose that can be delivered in 1 Often 4-6 x demand
Limit hour dose
4-Hour
Maximum total dose over 4 hours Set by provider
Limit
Demand Number of times the patient presses the button Documented in pump
Attempts (not all result in delivery) log
Demand Number of successful deliveries (actual doses Documented in pump
Deliveries received) log
�BASIC FORMULAS
, Formula 1: Hourly Maximum Dose
Hourly Maximum = Demand Dose × Number of Doses Allowed per Hour
*Where number of doses per hour = 60 minutes ÷ Lockout Interval (minutes)*
Example:
Demand dose = 1 mg morphine
Lockout interval = 10 minutes
Doses per hour = 60 ÷ 10 = 6
Hourly maximum = 1 mg × 6 = 6 mg/hour
Formula 2: 4-Hour Maximum Dose
4-Hour Maximum = Hourly Maximum × 4
Formula 3: Total Dose Received
Total Dose = (Demand Deliveries × Demand Dose) + (Basal Rate × Hours)
Formula 4: Medication Concentration Calculation
Volume to Administer = Desired Dose (mg) ÷ Concentration (mg/mL)
Analgesia (PCA)
Dosage Calculations
Comprehensive
Guide for Nursing
Students
�WHAT IS PCA?
Patient-Controlled Analgesia (PCA) is a method of pain management that allows
patients to self-administer predetermined doses of analgesic medication (typically
opioids) using a programmable pump. The patient controls the timing of medication
delivery by pressing a button, but the dose and frequency are limited by safety
parameters programmed by the healthcare provider.
,�KEY PCA TERMINOLOGY
Term Definition Typical Values
Demand The amount of medication delivered when the 0.5-2 mg morphine,
Dose patient presses the button 10-20 mcg fentanyl
The minimum time between doses; pump will
Lockout
not deliver if button is pressed during this 5-15 minutes
Interval
period
Continuous infusion of medication (background
Basal Rate 0.5-2 mg/hr morphine
rate)
Loading Initial bolus dose given to establish therapeutic
2-5 mg morphine IV
Dose effect before PCA started
1-Hour Maximum total dose that can be delivered in 1 Often 4-6 x demand
Limit hour dose
4-Hour
Maximum total dose over 4 hours Set by provider
Limit
Demand Number of times the patient presses the button Documented in pump
Attempts (not all result in delivery) log
Demand Number of successful deliveries (actual doses Documented in pump
Deliveries received) log
�BASIC FORMULAS
, Formula 1: Hourly Maximum Dose
Hourly Maximum = Demand Dose × Number of Doses Allowed per Hour
*Where number of doses per hour = 60 minutes ÷ Lockout Interval (minutes)*
Example:
Demand dose = 1 mg morphine
Lockout interval = 10 minutes
Doses per hour = 60 ÷ 10 = 6
Hourly maximum = 1 mg × 6 = 6 mg/hour
Formula 2: 4-Hour Maximum Dose
4-Hour Maximum = Hourly Maximum × 4
Formula 3: Total Dose Received
Total Dose = (Demand Deliveries × Demand Dose) + (Basal Rate × Hours)
Formula 4: Medication Concentration Calculation
Volume to Administer = Desired Dose (mg) ÷ Concentration (mg/mL)
