Talk to your doctor or pharmacist or nurse if you experience any of the following symptoms while taking Methadone Solution:
- Contact your doctor if you experience severe upper abdominal pain possibly radiating to the back, nausea, vomiting or fever as this could be symptoms associated with inflammation of the pancreas (pancreatitis) or the biliary tract system.
- Pain or increased sensitivity to pain (hyperalgesia) which does not respond to a higher dosage of your medicine.
Talk to your doctor before taking Methadone Solution if:
- you have liver or kidney problems
- you have problems with your gallbladder and bile duct
- you have epilepsy
- you have low thyroid function (hypothyroid)
- you have problems with your adrenal glands. These are linked to your kidneys
- you have an enlarged prostate gland
- you have low blood pressure
- you are in shock
- you have a muscle weakness disease called myasthenia gravis
- you have bowel problems
- you have a history of irregular heartbeat
- you have a history of heart disease
- you have a family history of people dying suddenly without cause
- you have low potassium, sodium or magnesium levels
- you are pregnant or breast-feeding
- you are extremely ill or an older person. You may be more sensitive to the medicine
- you are taking medicines called CNS depressants to treat anxiety, acute stress and panic attacks
- you have weakness, fatigue, lack of appetite, nausea, vomiting or low blood pressure. This may be a symptom of the adrenals producing too little of the hormone cortisol, and you may need to take hormone supplement.
Long-term use may cause decreased sex hormone levels and increased levels of the hormone prolactin. Contact your doctor if you experience symptoms such as decreased libido, impotence or absence of menstruation (amenorrhea).
Talk to your prescriber before taking this medicine for pain relief if you:
- have ever been addicted to opioids, alcohol, prescription medicines or illegal drugs.
- have previously suffered from withdrawal symptoms such as agitation, anxiety, shaking or sweating, when you have stopped taking alcohol or drugs.
- feel you need to take more of Methadone Solution to get the same level of pain relief, this may mean you are becoming tolerant to the effects of this medicine or are becoming addicted to it. Speak to your prescriber who will discuss your treatment and may change your dose or switch you to an alternative pain reliever.
If you are not sure if any of the above apply to you, talk to your doctor or pharmacist before taking Methadone Solution.
Tolerance, dependence, and addiction
This medicine contains methadone which is an opioid medicine. Repeated use of opioids can result in the drug being less effective (you become accustomed to it, known as tolerance). Repeated use of Methadone can also lead to dependence, abuse, and addiction, which may result in life-threatening overdose. The risk of these side effects can increase with a higher dose and longer duration of use.
Dependence or addiction can make you feel that you are no longer in control of how much medicine you need to take or how often you need to take it. When used for the treatment of pain, you might feel that you need to carry on taking your medicine, even when it doesn’t help to relieve your pain
The risk of becoming dependent or addicted varies from person to person. You may have a greater risk of becoming dependent or addicted on Methadone Solution if:
- You or anyone in your family have ever abused or been dependent on alcohol, prescription medicines or illegal drugs (“addiction”).
- You are a smoker.
- You have ever had problems with your mood (depression, anxiety, or a personality disorder) or have been treated by a psychiatrist for other mental illnesses.
If you notice any of the following signs whilst taking Methadone, it could be a sign that you have become dependent or addicted.
- You need to take the medicine for longer than advised by your doctor
- You need to take more than the recommended dose
- You are using the medicine for reasons other than prescribed, for instance, ‘to stay calm’ or ‘help you sleep’
- You have made repeated, unsuccessful attempts to quit or control the use of the medicine
- When you stop taking the medicine you feel unwell, and you feel better once taking the medicine again (‘withdrawal effects’)
If you notice any of these signs, speak to your doctor to discuss the best treatment pathway for you, including when it is appropriate to stop and how to stop safely (See section 3, If you stop taking Methadone Solution).
Taking this medicine regularly, particularly for a long time, can lead to addiction. Your prescriber should have explained how long you will be taking it for and when it is appropriate to stop, how to do this safely.
Rarely, increasing the dose of this medicine can make you more sensitive to pain. If this happens, you need to speak to your prescriber about your treatment.
Addiction can cause withdrawal symptoms when you stop taking this medicine. Withdrawal symptoms can include restlessness, difficulty sleeping, irritability, agitation, anxiety, feeling your heartbeat (palpitations), increased blood pressure, feeling or being sick, diarrhoea, loss of appetite, shaking, shivering or sweating. Your prescriber will discuss with you how to gradually reduce your dose before stopping the medicine. It is important that you do not stop taking the medicine suddenly as you will be more likely to experience withdrawal symptoms.
Opioids should only be used by those they are prescribed for. Do not give your medicine to anyone else. Taking higher doses or more frequent doses of opioid, may increase the risk of addiction. Overuse and misuse can lead to overdose and/or death.
Sleep-related breathing disorders
Methadone Solution can cause sleep-related breathing disorders such as sleep apnoea (breathing pauses during sleep) and sleep related hypoxemia (low oxygen level in the blood).The symptoms can include breathing pauses during sleep, night awakening due to shortness of breath, difficulties to maintain sleep or excessive drowsiness during the day. If you or another person observe these symptoms, contact your doctor. A dose reduction may be considered by your doctor.
Tell your doctor or pharmacist if you are taking or have recently taken any other medicines. This includes medicines bought without a prescription, including herbal medicines. This is because methadone can affect the way some other medicines work. Also, some medicines can affect the way methadone works.
The risk of side effects increases, if you take methadone at the same time as antidepressants (such as citalopram, duloxetine, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, venlafaxine, amitriptyline, clomipramine, imipramine, nortriptyline). Contact your doctor if you experience symptoms such as:
- mental-status changes (e.g. agitation, hallucinations, coma)
- fast heartbeat, unstable blood pressure, fever
- exaggeration of reflexes, impaired coordination, muscle stiffness
- gastrointestinal symptoms (e.g. nausea, vomiting, diarrhoea).
You must not take Methadone Solution:
- at the same time or within 2 weeks of taking Monoamine Oxidase Inhibitors (MAOIs).
Some medicines can increase the risk of heart problems when used with Methadone Solution. Talk to your doctor before taking Methadone Solution if you are taking:
- medicines for heart problems such as verapamil and enalapril
- medicines which affect electrolyte balance such as diuretics (water tablets) or lithium.
Tell your doctor if you are taking any of the following medicines:
- medicines that dull your senses such as:
- medicines to help you sleep (including anaesthetics)
- medicines to calm you down called tranquillisers
- serotonergic medicines used to treat migraine, such as sumatriptan
- cimetidine, used to treat stomach ulcers
- rifampicin, used to treat tuberculosis (TB)
- medicines used to treat epilepsy such as phenytoin, carbamazepine, phenobarbital and primidone
- medicines that make your urine acidic such as ascorbic acid (vitamin C)
- narcotic painkillers such as codeine and pentazocine
- naloxone used to reverse the effects of opioid drugs
- medicines used to stop opioid drugs working such as naltrexone and buprenorphine
- medicines used to treat HIV such as nevirapine, efavirenz, abacavir and nelfinavir. The doctor may have to change the amount of methadone you take whilst on these medicines
- antibiotics such as ciprofloxacin or macrolide antibiotics for example erythromycin
- medicines used to treat fungal infections such as ketoconazole or fluconazole
- St. John’s Wort - a herbal preparation for depression
- cyclizine, domperidone and metoclopramide, or serotonergic anti-emetics medicines such as ondansetron, used to treat nausea and vomiting
- medicines used to treat Parkinson’s disease and atropine
- mexiletine used to treat unusual heart rhythms
- lofexidine or clonidine, used to treat withdrawal effects
- other opioid type drugs e.g. morphine
- medicines used to treat pain and fever such as metamizole
- Cannabidiol (a medicine used to treat seizures)
- Gabapentin and pregabalin (medicines used to treat epilepsy, nerve pain or anxiety), can increase the risk of opioid overdose, respiratory depression (breathing difficulties) and may be life-threatening.
The use of Methadone Solution at the same time as sedative medicines such as benzodiazepines or related drugs increases the risk of drowsiness, difficulties in breathing (respiratory depression), coma and may be life-threatening. Because of this, taking Methadone Solution and sedative medicines at the same time should only be considered when other treatment options are not possible.
However, if your doctor does prescribe Methadone Solution together with sedative medicines the dose and duration of taking both treatments together should be limited by your doctor.
Please tell your doctor about all sedative medicines you are taking and follow your doctor’s dose recommendation closely. It could be helpful to inform friends or relatives to be aware of the signs and symptoms stated above. Contact your doctor if you experience such symptoms.
Other medicines you may be taking can also affect the heart. You must tell your doctor about any other medicines that you are taking as they may be dangerous if they are taken with methadone. In these situations, your doctor may decide that it is necessary to monitor your heart with an electrocardiogram (ECG) at the start of treatment to ensure that these effects do not occur.
If any of the above apply to you, talk to your doctor before taking Methadone Solution.