Morphine Dosage

Usual Adult Dose for Pain

Oral, Sublingual, or Buccal: 5 to 30 mg every 3 to 4 hours as needed
Extended release: range from 10 mg to 600 mg daily, given in equally divided doses every 8 to 12 hours or given as one dose every 24 hours
IM or subcutaneous: 2.5 to 20 mg every 3 to 4 hours as needed
IV: 4 to 15 mg every 3 to 4 hours as needed. Give very slowly over 4 to 5 minutes. Starting doses up to 15 mg every 4 hours have been used. Chest pain: 2 to 4 mg repeat as necessary
Continuous IV: 0.8 to 10 mg/hour. Maintenance dose: 0.8 to 80 mg/hour. Rates up to 440 mg/hour have been used.
IV patient controlled analgesia or subcutaneous patient controlled analgesia: 1 to 2 mg injected 30 minutes after a standard IV dose of 5 to 20 mg. The lockout period is 6 to 15 minutes. The 4 hour limit is 30 mg.
Continuous subcutaneous: 1 mg/hour after a standard dose of 5 to 20 mg
Epidural: 5 mg one time. May give 1 to 2 mg more after one hour to a maximum of 10 mg.
Intrathecal: 0.2 to 1 mg one time
Intrathecal Continuous: 0.2 mg/24 hours. May be increased up to 20 mg/24 hours.
Intracerebroventricular: 0.25 mg via an Ommaya reservoir.
Rectal: 10 to 30 mg every 4 hours as needed.

Usual Pediatric Dose for Pain

Less than or equal to 4 weeks:
Use preservative-free formulation:
Initial: 0.05 mg/kg IM, IV, or subcutaneously every 4 to 8 hours titrating carefully to effect
Maximum dose: 0.1 mg/kg/dose
Continuous Infusion: 0.01 mg/kg/hour continuous IV infusion. Do not exceed infusion rates of 0.015 to 0.02 mg/kg/hour.

Greater than or equal to 1 month but less than 12 years:
Oral: 0.2 to 0.5 mg/kg/dose every 4 to 6 hours (tablets/solution) or 0.3 to 0.6 mg/kg/dose every 12 hours (extended release)
IM,subcutaneous, IV: 0.05 to 0.2 mg/kg/dose (up to 15 mg) every 4 hours as needed.
IV/subcutaneous Continuous: 0.025 to 0.206 mg/kg/hour (sickle cell or cancer pain) or 0.01 to 0.04 mg/kg/hour (postop pain)
Epidural (use preservative-free formulation): 0.025 mg/kg/dose every 6 to 8 hours (postop pain). Maximum per 24 hours: 5 mg.

Greater than or equal to 12 years:
Premedication for anesthesia IV: 3 to 4 mg once, may repeat in 5 minutes if necessary.
Oral: 0.2 to 0.5 mg/kg/dose every 4 to 6 hours (tablets/solution) or 0.3 to 0.6 mg/kg/dose every 12 hours (extended release)
IM,subcutaneous, IV: 0.05 to 0.2 mg/kg/dose (up to 15 mg) every 4 hours as needed
IV/subcutaneous Continuous: 0.025 to 0.206 mg/kg/hour (sickle cell or cancer pain) or 0.01 to 0.04 mg/kg/hour (postop pain)
Epidural (use preservative-free formulation): 0.025 mg/kg/dose every 6 to 8 hours (postop pain). Maximum per 24 hours: 5 mg.
IV patient controlled analgesia: 0.015 mg/kg/dose (postop pain); lockout period of 10 minutes; 4 hour limit of 0.25 mg/kg.

Renal Dose Adjustments

In patients with end-stage renal disease start at the lower suggested dosage for the indication and the patient's needs, titrate dosage upwards slowly, and increase the dosage intervals to prevent accumulation of the metabolite morphine-6-glucoronide.

Liver Dose Adjustments

Data not available

Dose Adjustments

Titrate dosage slowly upward, taking into consideration the dosages received for breakthrough pain, to meet the specific needs of a patient.

Factors such as age, disease state, concomitant drug therapy, and tolerance to narcotics can have variable but important effects on dose and response. Women have been reported to require more morphine than men to achieve a similar degree of analgesia.

If a patient is not able to take oral morphine, divide the oral dose by half and give subcutaneously. If the IV route is preferred, the oral dose may be divided by 3.

The potency ration of oral to rectal morphine is 1:1.

Precautions

Serious adverse events and deaths have resulted from accidental overdose of morphine oral solutions. In most of these cases, morphine oral solutions ordered in milligrams (mg) were mistakenly interchanged for milliliters (mL) of the product. When this occurs with a high concentration oral solution, such as 100 mg/5 mL (20 mg/mL), the result is a 20 fold overdose. Healthcare providers should read the instructions in the Medication Guide that describe the correct use of the oral syringe in order to help prevent medication errors.

The extended-release formulations should not be broken, crushed, or chewed. These formulations should not be used for breakthrough pain or on as needed basis.

Extended release morphine capsules (Avinza, Kadian) may be opened and the entire contents may be sprinkled on a small amount of applesauce and consumed immediately. The contents of the capsules must not be chewed, crushed, or dissolved due to the risk of acute overdose.

Morphine, particularly in large doses or when administered by parenteral routes, may cause life-threatening respiratory depression. Treatment includes maintenance of the airway, artificial ventilation if necessary, and the opiate antagonist, naloxone (the usual adult dose of naloxone is 1 to 2 mg every 5 minutes as necessary). This dose can be administered intravenously, intramuscularly, subcutaneously and sublingually.)

Morphine, like other narcotic analgesics, should be administered with caution to patients with head injuries, increased intracranial pressure, acute undiagnosed abdominal pain, hypothyroidism, severe renal disease, severe liver disease, Addison's disease, prostatic hyperplasia, urethral stricture, and general debilitation. Even small doses of morphine may jeopardize cerebral circulation in the postoperative period following craniotomy.

Dialysis

A large percentage (50% to 100%) of a morphine dose is removed from circulation by hemodialysis.

Other Comments

Use only the preservative free injectable formulations for preparations given via the epidural and intrathecal routes, and in neonates.

Epidural pain or intrathecal pain relief may last up to 24 hours.

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