How does this medication work? What will it do for me?
Morphine belongs to the class of medications called narcotic analgesics (pain relievers). These pain relievers are also known as opioid analgesics. This medication relieves severe pain when less potent pain relievers are not effective. Opioids decrease pain by working on the brain to increase pain tolerance. Morphine immediate release works quickly. It will usually relieve pain within about 30 minutes.
This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.
Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.
What form(s) does this medication come in?
M.O.S is no longer being manufactured for sale in Canada. For brands that may still be available, search under morphine immediate release. This article is being kept available for reference purposes only. If you are using this medication, speak with your doctor or pharmacist for information about your treatment options.
How should I use this medication?
Doses of morphine vary widely and depend on the circumstances of an individual.
After a certain dose of morphine has been taken for a period of time, the body often gets used to it and a higher dose of morphine is needed to relieve the pain. Generally, your doctor will try to find the dose of morphine that will give you acceptable pain relief without an unacceptable level of side effects. This helps to reduce the side effects of the medication and allows for the dose to be adjusted upwards if needed. Always check with your doctor if you feel your medication isn't working well anymore.
Over time, this medication may produce tolerance and physical dependence as your body becomes used to the medication. Tolerance occurs when a dose that used to provide acceptable pain relief is no longer effective, and higher doses are required to achieve the same level of pain relief. Physical dependence is a state where the body will go into withdrawal if the medication is stopped suddenly. If you have been taking morphine on a regular basis for a long period of time, talk to your doctor before stopping the medication, as withdrawal effects can occur.
Tolerance and physical dependence are not the same as addiction. Addiction is defined as a psychological need to use the medication for reasons other than pain relief. Although people may become addicted to this medication, it is most common for people who have had addictions to other substances in the past.
Morphine tablets should be swallowed whole and not chewed, cut, broken, or crushed, which can be dangerous and lead to serious harm or death. Morphine capsules should be swallowed whole, or the capsules may be opened and the contents sprinkled on food. The liquid form of morphine may be mixed with a glass of fruit juice just before taking it to improve the taste.
If you are using a suppository, first remove the foil wrapper and moisten the suppository with cold water. Lie down on your side and use your finger to push the suppository well up into the rectum. If you find the suppository is too soft to insert, chill it in the refrigerator for 30 minutes or run cold water over it before removing the foil wrapper.
Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.
Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children. Accidental ingestion of this medication, especially by children, can have severe and even fatal consequences.
Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.
Who should NOT take this medication?
Do not take morphine if you:
- are allergic to morphine, or any ingredients of the medication
- are experiencing acute alcoholism or delirium tremens
- are experiencing acute asthma or other obstructive airway disease
- are experiencing acute respiratory depression
- are experiencing mild pain that can be treated with non-narcotic pain relievers
- are taking an MAO inhibitor such as phenelzine or tranylcypromine, or have taken one in the past 14 days
- have a blockage of the gastrointestinal tract, particularly paralytic ileus
- have or may have a surgical abdomen (e.g., acute appendicitis, pancreatitis)
- have a head injury, a brain tumour, or increased pressure inside the head or spinal cord
- have abnormal heart rhythms
- have convulsive (seizure) disorders
- have cor pulmonale
- have severe depression of the central nervous system (i.e., sedation)
- have a suspected abdominal condition that may require surgery
- are breast-feeding, pregnant, or in labour
What side effects are possible with this medication?
Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.
The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.
Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.
- changes in sexual desire or activity
- constipation (common with long-term use)
- decreased coordination
- dry mouth
- lightheadedness or feeling faint
- loss of appetite
- nausea or vomiting
- trouble sleeping
- unusual tiredness or weakness
Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- blurred or double vision or other changes in vision
- dizziness or light headedness when rising from a sitting or lying position
- fast, slow, or pounding heartbeat
- hives, itching, or skin rash
- increased sweating
- shortness of breath, wheezing, or troubled breathing
- symptoms of a bowel blockage (e.g., abdominal pain, severe constipation, nausea)
- withdrawal symptoms (e.g., nausea, vomiting, diarrhea, anxiety, shivering, cold and clammy skin, body aches, loss of appetite, sweating)
Stop taking the medication and seek immediate medical attention if any of the following occur:
- signs of overdose:
- cold, clammy skin
- convulsions (seizures)
- dizziness (severe)
- drowsiness (severe)
- low blood pressure
- nervousness or restlessness (severe)
- pinpoint-sized pupils of eyes
- slow heartbeat
- slow or troubled breathing
- weakness (severe)
- signs of serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
- symptoms of serotonin syndrome (e.g., confusion, fast heartbeat, hallucinations, restlessness, shaking, shivering, sudden jerking of muscles, sweating)
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.
Are there any other precautions or warnings for this medication?
Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Alcohol and other medications that cause drowsiness: Alcohol increases the risk of severe side effects from morphine, such as decreased blood pressure, seizures, breathing problems, and severe drowsiness. Consuming alcohol while you are taking morphine is not recommended. Other medications that cause drowsiness or slow down your breathing (e.g., antidepressants, sleeping pills, anxiety medications) should be avoided if possible, as additional side effects may occur which can be dangerous and potentially fatal.
Abdominal (stomach) conditions: Morphine and other narcotic medications may make the diagnosis of abdominal conditions more difficult or it may worsen these conditions. If you have abdominal or stomach problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Accidental use: Accidental ingestion or use of as little as one dose of morphine by someone for whom it has not been prescribed can lead to a fatal overdose. Children are especially at risk. Keep this medication out of sight and reach of children.
Adrenal gland problems: Adrenal glands produce chemical messengers that are responsible for the normal function of the body’s organs, including how your body responds to injury or stress. Morphine, like other opioid medications, may cause your adrenal gland to function improperly. Your doctor may monitor your adrenal gland condition especially if you have experienced stress such as surgery, injury, or severe infection.
Difficulty breathing: Morphine can cause serious and life-threatening breathing problems. If you experience slowed breathing or difficulty breathing, seek immediate medical attention. If you have lung problems and are taking other medications that can slow breathing, you are more at risk of experiencing these symptoms.
Make sure you follow the instructions on how to properly use this medication. If you have any questions, contact your doctor or pharmacist. If you have a chronic lung condition, such as bronchitis, emphysema, or asthma, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Dependence and withdrawal: Drug addiction is usually not a problem for people who require this medication for pain relief. Physical dependence (a need to take regular doses to prevent physical symptoms) has been associated with narcotic analgesics such as morphine. Withdrawal symptoms may be experienced if the dose is significantly reduced or suddenly discontinued. These symptoms include seizures, irritability, sleep problems, agitation, tremors, diarrhea, abdominal cramps, vomiting, headache, muscle cramps, extreme anxiety, tension, restlessness, sweating, and confusion. Reducing the dose gradually under medical supervision can help prevent or decrease these withdrawal symptoms when this medication is no longer required for pain control.
Drowsiness/reduced alertness: Morphine may impair the mental or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery. You should avoid such activities until you are certain this medication does not have this effect on you.
Head injury: Morphine can cause increased pressure inside the head. If you have an acute head injury or other conditions that increase your intracranial pressure (pressure inside the head), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Kidney function: If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Liver function: If you have reduced liver function or liver disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Low blood pressure: Morphine can cause low blood pressure or make low blood pressure worse. If you experience severe dizziness, especially when standing from a lying or sitting position, contact your doctor.
Other medical conditions: Morphine may cause increased symptoms or reduce the symptoms of worsening illness for people with the following conditions:
- Addison's disease
- enlarged prostate (BPH)
- irregular heart rhythms
- narrowing of the urethra
People with any of these conditions should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Seizures: Morphine may worsen preexisting seizure disorders. If tolerance to the medication develops and the dosage is increased substantially above recommended levels, even people without a history of seizure disorders may experience seizures. If you have a seizure disorder, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Serotonin syndrome: Severe reactions are possible when opioid medications such as morphine are combined with medications used to treat depression. Symptoms of a reaction may include muscle rigidity and spasms, difficulty moving, and changes in mental state including delirium and agitation. Coma and death are also possible. If you are taking medications for depression or migraine headaches, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Sleep apnea: Sleep apnea is a condition where you stop breathing for short periods while asleep. This can be caused or made worse by medications that slow breathing. If you or your partner notices episodes where you are not breathing then suddenly start to breathe again, contact your doctor as soon as possible.
Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. Withdrawal symptoms in newborns may be life-threatening and have been noted in newborns of mothers who used morphine during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: This medication passes into breast milk. If you are breast-feeding and are taking morphine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Seniors: Seniors may be more sensitive to the side effects of this medication and may require lower doses to reduce the risk of side effects.
What other drugs could interact with this medication?
There may be an interaction between morphine and any of the following:
- alpha-agonists (e.g., clonidine, methyldopa)
- alpha-blockers (e.g., alfuzosin, doxazosin, tamsulosin)
- amphetamines (e.g., dextroamphetamine, lisdexamfetamine)
- angiotensin-converting enzyme inhibitors (ACEIs; captopril, ramipril)
- angiotensin receptor blockers (ARBs; e.g., candesartan, irbesartan, losartan)
- antihistamines (e.g., azelastine, cetirizine, chlorpheniramine, dimenhydrinate, diphenhydramine, hydroxyzine, loratadine)
- antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
- "azole" antifungals (e.g., fluconazole, ketoconazole, voriconazole)
- barbiturates (e.g., butalbital, pentobarbital, phenobarbital)
- benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
- beta-blockers (e.g., atenolol, esmolol, metoprolol, propranolol)
- calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
- chloral hydrate
- diuretics (water pills; e.g., furosemide, hydrochlorothiazide)
- ergot alkaloids (e.g., ergotamine, dihydroergotamine)
- glecaprevir and pibrentasvir
- macrolide antibiotics (e.g., clarithromycin, erythromycin)
- monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, rasagiline, selegiline, tranylcypromine) taken within the last 14 days
- muscle relaxants (e.g., baclofen, cyclobenzaprine, methocarbamol, orphenadrine)
- other narcotic analgesics (e.g., codeine, fentanyl, meperidine, oxycodone, tramadol)
- phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
- St. John's wort
- seizure medications (e.g., carbamazepine, clobazam, levetiracetam, phenobarbital, phenytoin, primidone, rufinamide, topiramate, valproic acid, zonisamide)
- selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
- serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., desvenlafaxine, duloxetine, venlafaxine)
- tricyclic antidepressants (e.g., amitriptyline, imipramine, nortriptyline)
If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:
- stop taking one of the medications,
- change one of the medications to another,
- change how you are taking one or both of the medications, or
- leave everything as is.
An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.
Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.
All material copyright MediResource Inc. 1996 – 2023. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/drug/getdrug/MOS