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Methadone Hydrochloride Side Effects Center
Medical Editor: John P. Cunha, DO, FACOEP
Methadone Hydrochloride Tablets (methadone) is used as a pain reliever and as part of drug addiction detoxification and maintenance programs. It is a narcotic pain reliever. This medication is available in generic form. Common side effects include feeling anxious, nervous, or restless, sleep problems (insomnia), feeling weak or drowsy, dry mouth, nausea, vomiting, diarrhea, constipation, loss of appetite, decreased sex drive, impotence, or difficulty having an orgasm.
Dosing of methadone depends on the age, general condition and medical status of the patient, other medications being taken, and other factors. Methadone may interact with other narcotic pain medications, sedatives, tranquilizers, muscle relaxers, other medicines that can make you sleepy or slow your breathing, diuretics (water pills), antibiotics, heart or blood pressure medications, HIV medicines, MAO inhibitors, rifampin, or seizure medication. Many other medicines may cause serious medical problems if you take them together with methadone. Tell your doctor all prescription and over-the-counter medications and supplements you use. During pregnancy, Methadone should be used only if prescribed. It may be harmful to a fetus. It could also cause addiction or withdrawal symptoms in a newborn if the mother takes methadone during pregnancy. Methadone can pass into breast milk and may harm a nursing baby. Consult your doctor before breast-feeding. Withdrawal symptoms may occur if you suddenly stop using this medication.
Our Methadone Hydrochloride Tablets (methadone) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What is Patient Information in Detail?
Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
- shallow breathing;
- hallucinations or confusion;
- chest pain, dizziness, fainting, fast or pounding heartbeat; or
- trouble breathing, feeling light-headed, or fainting.
Less serious side effects may include:
- feeling anxious, nervous, or restless;
- sleep problems (insomnia);
- feeling weak or drowsy;
- dry mouth, nausea, vomiting, diarrhea, constipation, loss of appetite; or
- decreased sex drive, impotence, or difficulty having an orgasm.
This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.
Read the entire detailed patient monograph for Methadone Hydrochloride (methadone) »
What is Prescribing information?
The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.
Methadone Hydrochloride FDA Prescribing Information: Side Effects
During the induction phase of methadone maintenance treatment, patients are being withdrawn from heroin and may therefore show typical withdrawal symptoms, which should be differentiated from methadone-induced side effects. They may exhibit some or all of the following signs and symptoms associated with acute withdrawal from heroin or other opiates: lacrimation, rhinorrhea, sneezing, yawning, excessive perspiration, goose-flesh, fever, chilliness alternating with flushing, restlessness, irritability, weakness, anxiety, depression, dilated pupils, tremors, tachycardia, abdominal cramps, body aches, involuntary twitching and kicking movements, anorexia, nausea, vomiting, diarrhea, intestinal spasms, and weight loss.
The initial methadone dose should be carefully titrated to the individual. Too rapid titration for the patient's sensitivity is more likely to produce adverse effects.
The major hazards of methadone are respiratory depression and, to a lesser degree, systemic hypotension. Respiratory arrest, shock, cardiac arrest, and death have occurred.
The most frequently observed adverse reactions include lightheadedness, dizziness, sedation, nausea, vomiting, and sweating. These effects seem to be more prominent in ambulatory patients and in those who are not suffering severe pain. In such individuals, lower doses are advisable.
Other adverse reactions include the following:
Cardiovascular - arrhythmias, bigeminal rhythms, bradycardia, cardiomyopathy, ECG abnormalities, extrasystoles, flushing, heart failure, hypotension, palpitations, phlebitis, QT interval prolongation, syncope, T-wave inversion, tachycardia, torsade de pointes, ventricular fibrillation, ventricular tachycardia
Hematologic and Lymphatic - reversible thrombocytopenia has been described in opioid addicts with chronic hepatitis
Respiratory - pulmonary edema, respiratory depression
Skin and Appendages - pruritis, urticaria, other skin rashes, and rarely, hemorrhagic urticaria
Special Senses - hallucinations, visual disturbances
Urogenital - amenorrhea, antidiuretic effect, reduced libido and/or potency, urinary retention or hesitancy
Maintenance on a Stabilized Dose - During prolonged administration of methadone, as in a methadone maintenance treatment program, there is usually a gradual, yet progressive, disappearance of side effects over a period of several weeks. However, constipation and sweating often persist.
Drug Abuse And Dependence
Methadone contains methadone, a mu-agonist opioid with an abuse liability similar to other opioid agonists and is a Schedule II controlled substance. Methadone and other opioids used in analgesia have the potential for being abused and are subject to criminal diversion.
Drug addiction is characterized by compulsive use, use for non-medical purposes, and continued use despite harm or risk of harm. Drug addiction is a treatable disease, utilizing a multi-disciplinary approach, but relapse is common.
"Drug-seeking" behavior is very common in addicts and drug abusers. Drug-seeking tactics include emergency calls or visits near the end of office hours, refusal to undergo appropriate examination, testing or referral, repeated claims of lost prescriptions, tampering with prescriptions and reluctance to provide prior medical records or contact information for other treating physician(s). "Doctor shopping" (visiting multiple prescribers) to obtain additional prescriptions is common among drug abusers and people suffering from untreated addiction. However, it should be important to note that preoccupation with achieving adequate pain relief can be appropriate behavior in a patient with poor pain control.
Physical Dependence and Tolerance
Abuse and addiction are separate and distinct from physical dependence and tolerance. Physicians should be aware that addiction may not be accompanied by concurrent tolerance and symptoms of physical dependence in all addicts. In addition, abuse of opioids can occur in the absence of true addiction and is characterized by misuse for non-medical purposes, often in combination with other psychoactive substances. Methadone, like other opioids, has been diverted for non-medical use. Careful record-keeping of prescribing information, including quantity, frequency, and renewal requests is strongly advised.
Proper assessment of the patient, proper prescribing practices, periodic re-evaluation of therapy, and proper dispensing and storage are appropriate measures that help to limit abuse of opioid drugs.
Infants born to mothers physically dependent on opioids may also be physically dependent and may exhibit respiratory difficulties and withdrawal symptoms (see PRECAUTIONS, Pregnancy, Labor and Delivery).
Read the entire FDA prescribing information for Methadone Hydrochloride (methadone) »
Additional Methadone Hydrochloride Information
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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