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EQUIANALGESIC DOSING FOR MANAGEMENT OF ACUTE* OR CHRONIC PAIN

(Equivalent to Morphine 10mg IM/SC/IV)

Drug	IM/SC/IV (mg)	PO/PR/SL (mg)	Duration of Action (hrs)
AGONISTS
Morphine	10	20-30	3-4
Codeine	120-130	200	3-4
Hydromorphone	2	4	3-4
Oxycodone	-	15-20	3-4
Meperidine**	75-100	300	3
Fentanyl	100mcg (0.1mg)	-	2-3
Fentanyl Transdermal	25mcg/hr = 30- 66 mg IM/IV morphine/24hrs	25mcg/hr = 60-134mg PO morphine/24hrs	3 days
Methadone	-	Depends on morphine dose (see below)**	>6

* dose conversion is based on chronic pain management. May require lower IV doses for acute pain,
especially with IV bolus dosing
** not recommended for chronic pain management

- 2 x Tylenol #3 is approximately equivalent to 10mg PO morphine

- 2 x 292 is approximately equivalent to 10mg PO morphine.

- In round the clock administration of narcotics the IV/IM/SC routes are essentially equianalgesic.
- The oral, rectal, and sublingual routes are equianalgesic, if available
- Dosing frequency is usually based on the duration of action of the analgesic used; however,
certain individuals may obtain control with longer dosing intervals, and some patients may need
more frequent administration.
- Intravenous narcotics may have a shorter duration of action compared to other routes of administration.

**Daily chronic oral morphine equivalent	Conversion ratio morphine:methadone
< 100 mg	3:1
100-300mg	5:1
300-600mg	10:1
600-800mg	12:1
800-1000mg	15:1
> 1000 mg	20:1
**Caveat: Equivalence of methadone to morphine may vary considerably from one individual to another. Note that this Table is uni-directional ie. morphine to methadone conversion only.

Opioid analgesic dose conversions

morphine

Opioid analgesics are the cornerstone to treatment and control of severe pain. Equivalence of dose potency is not absolute and care must be taken in changing analgesics. In general, it is safer to use a lower regular dose with breakthrough analgesia rather than to convert immediately to the “equivalent” dose.

It is important nevertheless to know the approximately dosage conversions.

Equivalence to morphine 30 mg oral (1)

Drug

Dosage

Ratio

morphine (subcutaneous)

10 mg

1:3

morphine (intramuscular)

6 mg

1:5

morphine (intravenous) (2)

5 mg

1:6

oxycodone (oral) (3)

15 mg

1:2

hydromorphone (oral) (4)

6.5-7.5 mg

1:4-5

hydromorphone
(subcutaneous/intramuscular)

1.3-2.0 mg

1:15-25

fentanyl (transdermal patch)

50 mcg/hr (*)

complex

codeine (oral)

180 mg (**)

6:1

codeine (intramuscular)

120 mg (**)

4:1

(*)	Assuming morphine 30 mg (PO) q4-hourly dosing. Dose conversions to and from fentanyl transdermal patches are complex. Please refer to the prescriber guidelines, product information or a pain specialist.
(**)	There is usually little benefit in using doses of codeine phosphate above 60 mg per dose. Higher doses may lead to agitation and eu/dysphoria (5)

Conversion to oral slow release formulations

Conversion to oral dosing is usually fairly simple.

DO:

Calculate total dose of opioid analgesia taken over 24 hours;
convert to oral equivalent dose;
split the total daily oral dose into twice daily dosing (round down);
don’t forget to prescribe short acting analgesia for breakthrough pain (usually 50-100% of the regular dose per unit time).

An example:

A patient has received morphine 5 mg subcutaneously q4-hourly regularly and in the past 24 hours, received an additional three 5 mg subcutaneous bolus breakthrough doses. To convert into and regimen of oral morphine:

(Step One): Calculate total dose over 24 hours

regular doses: 5 mg x 6 doses = morphine 30 mg (s/c)
bolus doses: 5 mg x 3 doses = morphine 15 mg (s/c)
Total: morphine 45 mg (s/c) per 24 hours

(Step Two): Conversion to equivalent oral morphine

subcutaneous morphine to oral morphine ~ 1:3
Thus: 45 mg/day x 3
Oral equivalent daily dose: morphine 135 mg (PO) per 24 hours

(Step Three): Split into divided doses

Split dose (2 per day): morphine 135 mg (PO) / 2
Thus: morphine SR 67.5 mg per dose twice daily
Rounded down: morphine SR 60 mg (PO) twice daily

(Step Four): Breakthrough analgesia

Regular dose: morphine SR 60 mg (PO) per 12 hours
Breakthrough dose: (60 mg /12) x 50-100% = morphine 2.5-5.0 mg (PO) per hour
Given that oral (short acting) morphine is given every fourth hourly: 2.5-5.0 mg/hr x 4 hr
Breakthrough dose: morphine (immediate release) 10-20 mg (PO) q4-hourly PRN

Summary:

morphine SR 60 mg PO twice daily

morphine (imm. release) 10-20 mg PO q4-hourly PRN

After 24 hours, review the breakthrough (PRN) requirements. If a significant amount of breakthrough analgesia was required, this should be added to the regular analgesia.

Reference articles

(1) Examples of approximate equivalent doses when changing from morphine to another opioid (Table 10.7). Therapeutic guidelines: Analgesic, version 4, 2002.

(2) Morphine Sulfate Injection BP (DBL). MimsOnline. Last updated: 20 October 2005.

(3) OxyContin (oxycodone hydrochloride). MimsOnline. Last updated: 29 October 2004.

(4) Dilaudid (hydromorphone hydrochloride). MimsOnline. Last updated: 9 July 2004.

(5) Codeine Phosphate. MimsOnline. Last updated: 6 September 2001.

Cymbalta for Musculoskeletal Pain

Narcotic Analgesic

EQUIANALGESIC DOSING FOR MANAGEMENT OF ACUTE* OR CHRONIC PAIN

Opioid analgesic dose conversions

Opioid analgesic dose conversions