Morphine (Adverse effects)

Morphine is an opioid or narcotic analgesic obtained from the opium plant, popularly known as opium poppy. Morphine is used to treat intense pain since it is a very powerful analgesic: postoperative pain, intense chronic pain resistant to other analgesics, oncological pain, transient pain of severe intensity, pain associated with myocardial infarction.

Morphine is an analgesic agonist of μ opiate receptors, and to a lesser degree of kappa receptors, both in the central nervous system. Mophine binds to these receptors and decreases the sensitivity to pain.

This opiate can be administered orally (oral solution and tablets) and parenterally (subcutaneously, intravenously, intramuscularly, epidurally and intrathecally). The dose must be adapted individually to each patient, according to the severity of the pain and to the response to the analgesic.

In children it is only used exceptionally and in restricted doses, according to the body mass. Pregnant women are only given morphine when there is no alternative and, taking into account that the substance passes into breast milk, breastfeeding should be suspended when a treatment with morphine is established.


Hypersensitivity or allergy to morphine. Morphine is contraindicated during pregnancy and lactation. It should not be given to children under one year old. Do not provide morphine in patients suffering from respiratory depression or respiratory diseases with severe obstructions or in patients with traumatic brain injury or high intracranial pressure.

Morphine should not be given before surgery or in the first 24 hours after surgery.

Morphine is contraindicated in patients with seizure disorders.


Nausea and/or vomiting, alteration in the results of blood tests, drowsiness, disorientation, dizziness, instability, blurred vision, euphoria, sweating, dry mouth, constipation, respiratory alterations and/or variations in blood pressure, asthenia, pruritus, dependence and addiction (may occur if its use is prolonged).

Morphine can aggravate the condition of patients suffering from diseases such as: pancreatitis, asthma, COPD, alcoholism, hypotension, chronic constipation, hypothyroidism, severe liver or kidney disorders, among others.

Morphine can cause physical dependence in the fetus and abstinence syndrome in the baby if it is administered to a pregnant woman. In addition, it passes into breast milk, so it should not be used during breastfeeding.


  • Morfina Braun®
  • Morfina clorhidrato®
  • MST Continus®
  • Oramorph®
  • Sevredol®
  • Zomorph®
  • Dolq®

Gene or region studied

  • FAAH
  • OCT1
  • ABCB1
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