Morphine Sulfate ER Side Effects

Generic Name: morphine

Note: This page contains information about the side effects of morphine. Some of the dosage forms included on this document may not apply to the brand name Morphine Sulfate ER.

Not all side effects for Morphine Sulfate ER may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to morphine: oral capsule, oral capsule delayed release, oral capsule extended release, oral capsule extended release 24 hr, oral powder for suspension extended release, oral solution, oral syrup, oral tablet, oral tablet extended release

In addition to its needed effects, some unwanted effects may be caused by morphine (the active ingredient contained in Morphine Sulfate ER). In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking morphine:

Less common
  • Abdominal or stomach pain
  • blurred vision
  • bulging soft spot on the head of an infant
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • change in the ability to see colors, especially blue or yellow
  • chest pain or discomfort
  • confusion
  • cough
  • decreased urination
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fainting
  • fast, pounding, or irregular heartbeat or pulse
  • headache
  • hives, itching, or skin rash
  • increased sweating
  • loss of appetite
  • nausea or vomiting
  • nervousness
  • pounding in the ears
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • severe constipation
  • severe vomiting
  • shakiness in the legs, arms, hands, or feet
  • shortness of breath
  • slow heartbeat
  • sweating or chills
  • wheezing
Incidence not known
  • Black, tarry stools
  • cold, clammy skin
  • feeling of warmth or heat
  • flushing or redness of the skin, especially on the face and neck
  • irregular, fast or slow, or shallow breathing
  • lightheadedness
  • loss of consciousness
  • low blood pressure or pulse
  • painful urination
  • pale or blue lips, fingernails, or skin
  • pale skin
  • pinpoint red spots on the skin
  • pounding in the ears
  • shakiness and unsteady walk
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • unusual bleeding or bruising
  • very slow heartbeat

If any of the following symptoms of overdose occur while taking morphine, get emergency help immediately:

Symptoms of overdose
  • Constricted, pinpoint, or small pupils (black part of the eye)
  • decreased awareness or responsiveness
  • extreme drowsiness
  • fever
  • increased blood pressure
  • increased thirst
  • lower back or side pain
  • muscle cramps or spasms
  • muscle pain or stiffness
  • no muscle tone or movement
  • severe sleepiness
  • swelling of the face, fingers, or lower legs
  • weight gain

Some of the side effects that can occur with morphine may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Cramps
  • difficulty having a bowel movement (stool)
  • drowsiness
  • false or unusual sense of well-being
  • relaxed and calm feeling
  • sleepiness or unusual drowsiness
  • weight loss
Less common
  • Absent, missed, or irregular menstrual periods
  • agitation
  • bad, unusual, or unpleasant (after) taste
  • change in vision
  • depression
  • dry mouth
  • face is warm or hot to touch
  • floating feeling
  • halos around lights
  • heartburn or indigestion
  • loss in sexual ability, desire, drive, or performance
  • muscle stiffness or tightness
  • night blindness
  • overbright appearance of lights
  • problems with muscle control
  • redness of the skin
  • skin rash
  • stomach discomfort, upset, or pain
  • trouble sleeping
  • uncontrolled eye movements
Incidence not known
  • Abnormal dreams
  • change in walking and balance
  • change or problem with discharge of semen
  • clumsiness or unsteadiness
  • confusion as to time, place, or person
  • delusions
  • dementia
  • feeling of constant movement of self or surroundings
  • general feeling of discomfort or illness
  • holding false beliefs that cannot be changed by fact
  • problems with memory
  • seeing, hearing, or feeling things that are not there
  • sensation of spinning
  • unusual excitement, nervousness, or restlessness

For Healthcare Professionals

Applies to morphine: compounding powder, injectable solution, injectable tablet soluble, intravenous solution, oral capsule, oral capsule extended release, oral concentrate, oral solution, oral tablet, oral tablet extended release, rectal suppository

Nervous system

Central nervous system side effects may be either depressant or excitatory. Excitatory symptoms are sometimes ignored as possible side effects of morphine (the active ingredient contained in Morphine Sulfate ER) Severe adverse effects such as respiratory depression can be treated with the opioid antagonist naloxone.

Patients receiving continuous infusion of morphine sulfate via indwelling intrathecal catheter should be monitored for new neurologic signs or symptoms. Further assessment or intervention should be based on the clinical condition of the individual patient.

Myoclonic spasms may occur in patients receiving high dose morphine, particularly in the setting of renal dysfunction. Hyperalgesia has also been reported with high doses.

Nervous system side effects have been frequently reported and include drowsiness and sedation. Inflammatory masses including granulomas (some of which have resulted in serous neurologic impairment including paralysis) have been reported to occur in patients receiving continuous infusion of opioid analgesics including morphine sulfate via indwelling intrathecal catheter. Delirium, seizures, tremors, dizziness, muscle twitches, malaise, and confusion have also been reported.


Respiratory side effects including respiratory depression have been reported frequently. Bronchospasm has been reported in patients with underlying pulmonary disease.


Gastrointestinal side effects including nausea, vomiting, dyspepsia, constipation, dry mouth, increased gastroesophageal reflux, intestinal obstruction, and increased biliary pressure have been reported.

Morphine may cause constriction of the common bile duct and spasm of the sphincter of Oddi, thereby increasing intrabiliary pressure and worsening, rather than relieving, biliary colic.

In addition, morphine may cause intense but uncoordinated duodenal contraction and decreased gastric emptying.


Withdrawal symptoms have been reported to have included agitation, restlessness, anxiety, piloerection, insomnia, convulsions, tremor, abdominal cramps, blurred vision, vomiting, and sweating.

Other side effects include a withdrawal symptoms after either abrupt cessation or fast tapering of morphine.


Cardiovascular side effects including hypotension related to a transient decrease in systemic arterial resistance has been reported, particularly in the setting of myocardial infarction.


Psychiatric side effects have included fearfulness, agitation, thinking disturbances, paranoia, psychosis, hypervigilance, and hallucinations.


Genitourinary side effects including acute urinary retention have been reported.

The risk of acute urinary retention is very high when morphine is administered by epidural or intrathecal injection. Clinicians should be attentive to the increased risk of urosepsis in this setting, particularly if instrumentation of the urinary tract is necessary.


Hematologic side effects including immune thrombocytopenia has been rarely reported.


Endocrine side effects such as menstrual irregularities including amenorrhea have been reported. Reduced male potency and decreased libido in both men and women have also been reported.


Musculoskeletal side effects including opioid-induced involuntary muscle hyperactivity has been reported with chronic, high doses.


Dermatologic side effects including sweating, flushing, pruritus have been reported frequently. A case of acute generalized exanthematous pustulosis has also been reported.


Ocular side effects include keratoconjunctivitis and allergic conjunctivitis associated with lid urticaria. Visual disturbances and miosis have also been reported. A study has reported a temporary 26% decrease in pupil diameter following the administration of IV morphine (the active ingredient contained in Morphine Sulfate ER)


Hypersensitivity reactions including anaphylactoid reactions have been reported to occur very rarely.


Droperidol (2.5 mg intravenously) has been used successfully to reverse the pruritus associated with epidural morphine (the active ingredient contained in Morphine Sulfate ER) 2 or 4 mg dosages. A larger dose of droperidol (5 mg) unexplainably does not appear to reverse the pruritus.

General side effects including a sense of warmth has been frequently reported.


Hepatic side effects including increases in hepatic enzymes have been reported infrequently.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.