Morphine (MST continus tablets)
How does it work?
MST continus tablets contain the active ingredient morphine sulphate, which is a type of medicine called an opioid painkiller.
Opioid painkillers work by mimicking the action of naturally occurring pain-reducing chemicals called endorphins. Endorphins are found in the brain and spinal cord and reduce pain by combining with opioid receptors.
Morphine mimicks the action of endorphins by combining with the opioid receptors in the brain and spinal cord. This blocks the transmission of pain signals sent by the nerves to the brain. Therefore, even though the cause of the pain may remain, less pain is actually felt.
Morphine is used to relieve severe pain, for example associated with cancer or severe injury.
MST continus tablets are known as prolonged release tablets. They are designed to release the morphine slowly and continuously over 12 hours to help provide steady blood levels of the medicine throughout the day and hence prolonged pain relief. The tablets should be taken every 12 hours. They must be swallowed whole and not broken, chewed or crushed, as this would damage the prolonged release action and could lead to the rapid release and absorption of a potentially fatal dose of morphine.
What is it used for?
- Prolonged relief of severe pain.
- Relief of pain following surgery.
- MST continus tablets must be swallowed whole and not broken, crushed or chewed (see above).
- This medicine may cause drowsiness. If affected do not drive or operate machinery. Alcohol should be avoided.
- If this medicine is taken for prolonged periods of time, the body can become tolerant to it and it may become less effective at relieving pain. This means that with time, higher doses may be needed to control pain. With prolonged use the body may also become dependent on the medicine. As a result, withdrawal symptoms can occur if the medicine is stopped suddenly. For this reason, when a person no longer needs this medicine it may be necessary to reduce treatment gradually to avoid withdrawal symptoms.
Use with caution in
- Elderly people.
- Decreased kidney function.
- Decreased liver function.
- People with decreased lung function or breathing difficulties, for example asthma.
- History of convulsions (fits), eg epilepsy.
- Low blood pressure (hypotension) and low circulating blood volume (hypovolaemia).
- Severe enlargement of the right side of the heart due to high blood pressure in the pulmonary artery (cor pulmonale).
- Diseases of the bile ducts.
- Inflammation of the pancreas (pancreatitis).
- Inflammatory bowel disease such as ulcerative colitis or Crohn's disease.
- Enlarged prostate gland (prostatic hypertrophy).
- Underactive thyroid gland (hypothyroidism).
- Lack of production of natural steroid hormones from the adrenal gland (adrenocortical insufficiency).
- People dependent on opioids.
- History of drug or alcohol abuse.
- Serious medical condition caused by withdrawal from alcohol (delirium tremens).
- MST continus tablets should be used with caution following operations, particularly surgery on the gut.
Not to be used in
- Children under one year of age.
- Slow, shallow breathing (respiratory depression).
- Obstructive airways disease.
- Head injury.
- Increased pressure in the brain (raised intracranial pressure).
- People with inactivity of the intestine that stops material passing through the gut (paralytic ileus).
- People with delayed emptying of the stomach contents into the intestine.
- Sudden emergency conditions affecting one or more of the organs in the abdomen (acute abdomen, eg appendicitis).
- Acute liver disease.
- People who have taken a monoamine-oxidase inhibitor antidepressant (MAOI) in the last 14 days.
- MST continus tablets are not recommended to relieve pain before surgery, or in the first 24 hours following operations (until normal bowel function has returned). They are not recommended for relieving pain following surgery in children.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- This medicine is not recommended for use during pregnancy or labour because it may cause breathing difficulties in the baby. Babies born to mothers who have been having long-term treatment with this medicine may have withdrawal symptoms after birth. Seek medical advice from your doctor.
- This medicine passes into breast milk. It is not recommended for use by breastfeeding women. Seek medical advice from your doctor.
- This medication is to be swallowed whole, not chewed.
- This medication may cause drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drink.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
- Nausea and vomiting.
- Loss of appetite.
- Dry mouth.
- Rash or itching.
- Feeling weak.
- Muscle rigidity.
- Increased blood flow to the skin on the face (facial flushing).
- Problems with urinating.
- Breathing difficulties due to a narrowing of the airways (bronchospasm).
- Changes in mood.
- False perceptions of things that are not really there (hallucinations).
- Slow, shallow breathing (respiratory depression).
- Awareness of your heartbeat (palpitations).
- Low blood pressure (hypotension).
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.
This medicine should not be taken by people who are taking a monoamine oxidase inhibitor antidepressant (MAOI), for example the antidepressants phenelzine, tranylcypromine or isocarboxacid, or by people who have taken one of these medicines in the last 14 days.
There may be an increased risk of drowsiness and sedation if this medicine is taken with any of the following (which can also cause drowsiness):
- antipsychotics, eg haloperidol
- barbiturates, eg phenobarbital, amobarbital
- benzodiazepines, eg diazepam, temazepam
- other opioids, eg codeine, tramadol
- sedating antihistamines, eg chlorphenamine, hydroxyzine
- sleeping tablets, eg zopiclone
- tricyclic antidepressants, eg amitriptyline.
There may be an increased risk of breathing difficulties if cimetidine is taken with morphine.
Morphine may oppose the effects of the following medicines on the gut:
The following medicines may reduce the amount of morphine in the blood and could make it less effective:
Other medicines containing the same active ingredient
|Morphgesic SR tablets ||MST continus suspension ||MXL capsules |
|Oramorph ||Sevredol tablets ||Zomorph capsules |
Morphine is also available generically as an injection, oral solution and suppositories.