From the Guidelines
Morphine can cause several side effects, including constipation, nausea, vomiting, drowsiness, dizziness, and respiratory depression, with constipation being nearly universal with regular use and should be proactively managed with stool softeners and laxatives 1.
Common Side Effects of Morphine
- Constipation: nearly universal with regular use, should be proactively managed with stool softeners and laxatives
- Nausea and vomiting: typically improve after a few days of use
- Drowsiness and dizziness: can impair coordination and judgment, patients should avoid driving or operating machinery until they know how morphine affects them
- Respiratory depression: the most serious side effect, can be life-threatening, especially with higher doses or in opioid-naive patients
Management of Side Effects
- Laxatives should be prescribed during the treatment period to prevent constipation, along with advice on diet and hydration 1
- Antiemetics should be prescribed for a few days if nausea and vomiting persist 1
- Dose reduction or change of medication may be necessary if side effects are intolerable 1
Serious Side Effects
- Respiratory depression: can be life-threatening, especially with higher doses or in opioid-naive patients
- Other potential side effects include urinary retention, itching, dry mouth, sweating, headache, and mood changes
Long-term Effects
- Physical dependence and tolerance: may develop with prolonged use, requiring higher doses for the same pain relief
- Morphine can also cause pupil constriction, decreased blood pressure, and slowed heart rate, due to its binding to mu-opioid receptors in the brain, spinal cord, and digestive tract, altering pain perception and affecting multiple body systems 1
From the FDA Drug Label
6 ADVERSE REACTIONS
The following serious adverse reactions are described, or described in greater detail, in other sections: Addiction, Abuse, and Misuse [see Warnings and Precautions (5.1)] Life-Threatening Respiratory Depression [see Warnings and Precautions (5.3)] Neonatal Opioid Withdrawal Syndrome [see Warnings and Precautions (5. 4)] Interactions with Benzodiazepine or Other CNS Depressants [see Warnings and Precautions (5.5)] Adrenal Insufficiency [see Warnings and Precautions (5.8)] Severe Hypotension [see Warnings and Precautions (5.9)] Gastrointestinal Adverse Reactions [see Warnings and Precautions (5.11)] Seizures [see Warnings and Precautions (5.12)] Withdrawal [see Warnings and Precautions (5. 13)] The following adverse reactions associated with the use of morphine were identified in clinical studies or post-marketing reports. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure Serious adverse reactions associated with morphine use included: respiratory depression, apnea, and to a lesser degree, circulatory depression, respiratory arrest, shock and cardiac arrest. The common adverse reactions seen on initiation of therapy with morphine were dose-dependent and were typical opioid-related adverse reactions The most frequent of these included: constipation, nausea, and somnolence. Other commonly observed adverse reactions included: lightheadedness, dizziness, sedation, vomiting, and sweating.
The side effects of morphine include:
- Serious adverse reactions:
- Respiratory depression
- Apnea
- Circulatory depression
- Respiratory arrest
- Shock
- Cardiac arrest
- Common adverse reactions:
- Constipation
- Nausea
- Somnolence
- Lightheadedness
- Dizziness
- Sedation
- Vomiting
- Sweating
- Other adverse reactions:
- Skeletal muscle rigidity
- Decreased bone mineral density
- Abnormal dreams
- Abnormal gait
- Agitation
- Amnesia
- Anxiety
- Ataxia
- Confusion
- Convulsions
- Coma
- Delirium
- Depression
- Dry mouth
- Euphoria
- Hallucinations
- Lethargy
- Nervousness
- Abnormal thinking
- Tremor
- Vasodilation
- Vertigo
- Headache
- Hiccup
- Hypoventilation
- Voice alteration
- Dry skin
- Urticaria
- Pruritus
- Amblyopia
- Eye pain
- Taste perversion
- Abnormal ejaculation
- Dysuria
- Impotence
- Decreased libido
- Oliguria
- Urinary retention or hesitancy
- Anti-diuretic effect
- Amenorrhea
- Serotonin syndrome
- Adrenal insufficiency
- Anaphylaxis
- Androgen deficiency 2
From the Research
Side Effects of Morphine
The side effects of morphine, an opioid analgesic, have been extensively studied in various clinical settings. Some of the most common side effects include:
- Constipation: a very high incidence, often severe, and may not develop tolerance 3
- Nausea: common, may be severe, and can limit the effective analgesic dosage 4, 5, 3, 6
- Vomiting: frequent, especially in the first 24 hours of treatment 5, 7, 6
- Sedation: common, may be moderate or severe, and can be a concern for patient safety 4, 5, 3
- Dry mouth: often moderate to severe in intensity and persistent 4
- Myoclonus: common, usually mild, but can be a concern for some patients 4, 3, 7
- Dizziness: a common side effect, especially in the initial stages of treatment 3
- Physical dependence and tolerance: clinical concerns that may prevent proper prescribing and adequate pain management 3
- Respiratory depression: a less common but potentially life-threatening side effect 3, 7
Less Common Side Effects
Some less common side effects of morphine include:
- Delayed gastric emptying: a potential concern for patients with gastrointestinal issues 3
- Hyperalgesia: an increased sensitivity to pain, which can be a challenge to manage 3, 7
- Immunologic and hormonal dysfunction: potential long-term effects of opioid therapy 3
- Muscle rigidity: a less common side effect, but can be a concern for some patients 3
- Urinary retention: a potential side effect, especially in patients with pre-existing urinary issues 7
- Sexual dysfunction: a potential concern for patients on long-term opioid therapy 7
- Edema: a less common side effect, but can be a concern for patients with pre-existing cardiovascular issues 7
- Catheter tip inflammatory mass formation: a rare but potentially serious complication of intrathecal morphine therapy 7