morphine injection (Astramorph, Duramorph, Infumorph)

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GENERIC NAME: morphine injection

BRAND NAMES: Astramorph, Duramorph, Infumorph

DRUG CLASS AND MECHANISM: Morphine is a chemical found in the opium plant. It is a narcotic (opiod) pain-reliever similar to hydrocodone, oxycodone, methadone, fentanyl, and other opioids. Morphine, like other opioids, stimulates receptors on nerves in the brain to increase the threshold to pain (increasing the amount of stimulation it takes to feel pain) and reduce the perception of pain (the perceived importance of the pain). The FDA approved injectable morphine in October 1986.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Solution 0.5, 2, 4, 5, 8, 10, 15, 25, and 50 mg/mL in 1, 2, 10, 20, 30, 50, and 250 mL ampules or vials. There is a preservative-free formulation for intrathecal and epidural (spinal) administration.

STORAGE: Morphine injection solution should be protected from light and stored at room temperature, between 15 C to 30 C (59 F to 86 F).

PRESCRIBED FOR: Morphine through intravenous, epidural, or intrathecal injections is used for the management of moderate-to-severe acute and chronic pain that is not responsive to non-narcotic pain relievers.

DOSING: Dosing is specific to the route of administration.

  • In adults (at least 18 years of age) the initial intravenous dose should be 2 to 10 mg per 70 kg of body weight over 24 hours.
  • For epidural administration, 5 mg may be administered initially, with a maximum dose of 10 mg over 24 hours.
  • Initial dosing for intrathecal administration should be 0.2 to 1 mg over 24 hours.

DRUG INTERACTIONS: Combining alcohol and other sedatives with morphine can lead to increased sedation and even cause confusion.

Fluoxetine (Prozac) may increase blood levels and the effect of morphine leading to increased side effects.

Morphine should also be avoided in patients treated with monoamine oxidase inhibitors (MAOI) due to enhance toxicity of morphine including confusion, high blood pressure, tremor, hyperactivity, coma, and death. Drugs in this class include isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), selegiline (Eldepryl), and procarbazine (Matulane), and linezolid (Zyvox). Morphine should not be administered within 14 days of stopping an MAOI.

PREGNANCY: Morphine injection should only be given to pregnant women when no other method of controlling pain is available and there are methods to monitor the fetus. Newborns may exhibit withdrawal symptoms if chronic dosing is used.

NURSING MOTHERS: Morphine is excreted in breast milk, however, the American Academy of Pediatrics committee states that it is safe to use while nursing.

SIDE EFFECTS: The most frequent adverse reactions of morphine include dry mouth, constipation, nausea, vomiting, drowsiness, dizziness, and difficulty urinating. Other side effects include low blood pressure, slowed heart rate, itching, fever, confusion, headache, weakness, and decreased oxygen delivery to the body. Patients may also develop anemia with intrathecal injection, and pain at the injection site. The elderly may be more sensitive to adverse effects. Morphine has the potential to be habit forming. Tolerance and physical and psychological dependence may occur with prolonged use. Seizures may result from high doses. Overdoses may cause respiratory depression, coma, and death.

REFERENCE: FDA Prescribing Information


Last Editorial Review: 4/23/2014




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