What is Methadone?
Methadone is an opioid (or narcotic) drug and a controlled substance - this drug has a risk of misuse and may cause dependence.
Methadone is also available as the brand-name drug Methadose. It is used as an oral soluble tablet.
What is Methadone Used For?
Methadone is used to treat moderate to severe pain.
It is sometimes prescribed in cases where the patient has an addiction to another opioid. Methadone helps prevent withdrawal symptoms.
Methadone relieves pain by changing the way your brain and the nervous system respond to pain. It does so by working on the pain receptors.
Methadone relieves pain much slower than other painkillers like morphine.
Side Effects of Methadone
Some common side effects of methadone are:
- Constipation
- Nausea
- Sleepiness
- Vomiting
- Tiredness
- Headache
- Dizziness
- Stomach Pain
Some serious side effects are:
- Shortness of breath
- Chest pain
- Lightheadedness
- Feeling faint
- Increased blood pressure
- Fast breathing rate
- Fast heart rate
- Chills
- Muscle aches and backache
- Seizures
Drug Interactions
Opioid medication can interact with many other drugs and cause dangerous side effects. Make sure you notify your doctor if you use other:
- Narcotic medications
- Sedatives like valium
- Benzodiazepines (sleeping pills)
- Antidepressants or other drugs that can affect serotonin levels in the body.
Gene-Drug Interactions
UGT2B7 And Withdrawal Symptoms In Methadone Maintenance Patients
Methadone maintenance treatment is the use of methadone for a prolonged period of time to treat pain in patients who have faced addiction issues with other opioids like heroin.
The UGT2B7 gene is located at chromosome 4q13. It contains instructions for the production of UDP-Glucuronosyltransferase-2B7.
It is associated with withdrawal symptoms, treatment efficacy, and side effects in methadone maintenance treatment.
rs4292394
rs4292394 is a single nucleotide polymorphism or SNP in the UGT2B7 gene. It is associated with opioid withdrawal when undergoing methadone maintenance treatment.
| Genotype | Effect |
| GG | May have increased severity of opiate withdrawal symptoms |
| CG | May have decreased severity of opiate withdrawal symptoms |
| CC | May have decreased severity of opiate withdrawal symptoms |
CYP3A4 and Methadone Toxicity
The CYP3A enzymes are the most abundant of the CYP450 isozymes, comprising ∼40% of the hepatic CYP450 content.
The CYP3A4 gene contains instructions for the production of the Cytochrome P 450 3A4 enzyme. CYP3A4 plays a role in the metabolism of 40–60% of all drugs ingested.
A few studies have reported the role of CYP3A4 polymorphisms in methadone toxicity.
rs4646437
rs4646437 is an SNP in the CYP3A4 gene. Studies have demonstrated that the CYP3A4 enzyme expression and activity are increased in females carrying the T allele.
Increased levels of CYP3A4 result in increased conversion of methadone to inactive metabolites (substances that result from the metabolism of methadone). This increases the risk of fatal methadone intoxication in the female population with the T allele.
Recommendations for Safe Methadone Consumption
Pre-existing Medical Conditions
Notify your doctor of any health conditions you may have, like heart, lung, or kidney disease, as methadone may not be safe to consume in these cases.
Current Medications
Make sure your doctor knows all the drugs you are currently on/have had in the recent past in order to avoid drug interactions.
Pregnant or Breastfeeding Women
Women who are pregnant or breastfeeding may take methadone; however, methadone can cross the placenta and can go into the breast milk. So seek the advice of your medical practitioner if you are pregnant or breastfeeding.
The Correct Dosage
The correct dosage varies according to the purpose - whether to treat pain, for detoxification of opioid addiction, or for maintenance of opioid addiction.
In case you take too much or experience symptoms of overdosing like slow pulse, cold, clammy skin, slowed breathing, or dizziness, immediately call your doctor or local poison control. If the symptoms are severe, call 911.
Allergic Reaction
Methadone can cause severe allergic reactions. If you have trouble breathing or experience swelling of your tongue and throat, seek medical attention immediately.
Summary
- Methadone is an opioid drug used to treat moderate to severe pain. It is also prescribed to people who suffer from other opioid addictions.
- The common side effects of methadone include nausea, vomiting, and stomach pain, and the serious ones include chest pain, increased blood pressure, and seizures.
- Methadone Maintenance Treatment (MMT) is used with patients who have had opioid addiction issues.
- People with a certain type of the UGT2B7 gene may have an increased risk for severe opioid withdrawal symptoms than others when on MMT.
- The CYP3A4 gene has been associated with methadone toxicity. Females with a particular type of this gene are at increased risk for methadone toxicity.
- While taking methadone, it is important to notify your doctor of your existing medical conditions as well as the list of drugs you are on.
- Pregnant and breastfeeding women can take methadone only after consulting with the doctor.
- In case of overdose or any allergic reaction, reaching out for immediate medical help is crucial.
