Methadone Side Effects
Not all side effects for methadone may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.
For the Consumer
Applies to methadone: oral liquid, oral solution, oral tablet, oral tablet for suspension
In addition to its needed effects, some unwanted effects may be caused by methadone. In the event that any of these side effects do occur, they may require medical attention.
You should check with your doctor immediately if any of these side effects occur when taking methadone:Incidence not known
- Black, tarry stools
- bleeding gums
- blood in the urine or stools
- blurred vision
- bulging soft spot on the head of an infant
- change in the ability to see colors, especially blue or yellow
- changes in skin color
- chest discomfort or pain
- coughing that sometimes produces a pink frothy sputum
- decreased urine output
- difficult or troubled breathing
- difficult, fast, noisy breathing, sometimes with wheezing
- difficulty with swallowing
- dilated neck veins
- dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
- dry mouth
- extreme fatigue
- fast, slow, or irregular heartbeat
- hives, itching, or skin rash
- increased sweating
- increased thirst
- irregular heartbeat recurrent
- irregular, fast or slow, or shallow breathing
- loss of appetite
- muscle pain or cramps
- nausea or vomiting
- numbness or tingling in the hands, feet, or lips
- pale or blue lips, fingernails, or skin
- pinpoint red spots on the skin
- puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
- swelling of the face, fingers, feet, or lower legs
- trouble sleeping
- trouble urinating
- unusual bleeding or bruising
- unusual tiredness or weakness
- weight gain
Some of the side effects that can occur with methadone may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:Incidence not known
- Absent, missed, or irregular menstrual periods
- blurred or loss of vision
- confusion about identity, place, and time
- decreased interest in sexual intercourse
- disturbed color perception
- double vision
- false or unusual sense of well-being
- halos around lights
- inability to have or keep an erection
- lack or loss of strength
- loss in sexual ability, desire, drive, or performance
- night blindness
- overbright appearance of lights
- redness, swelling, or soreness of the tongue
- stopping of menstrual bleeding
- tunnel vision
- weight changes
For Healthcare Professionals
Applies to methadone: compounding powder, injectable solution, oral concentrate, oral solution, oral tablet, oral tablet dispersible
Other neurologic side effects are rare, but include tardive dyskinesia and choreic movements.
Nervous system side effects have included agitation, confusion, disorientation, dysphoria, euphoria, seizures, sleepiness or insomnia, and dizziness.
Cardiovascular side effects have included hypotension, bradycardia, arrhythmias, bigeminal rhythms, cardiomyopathy, ECG abnormalities, extrasystoles, flushing, heart failure, palpitations, phlebitis, QT interval prolongation, syncope, T-wave inversion, tachycardia, torsade de pointes, ventricular fibrillation, ventricular tachycardia and edema. Rare cases of cardiac arrest have also been reported.
Methadone may cause contraction of the sphincter of Oddi, which may increase intrabiliary pressure and worsen, rather than relieve, biliary colic.
Gastrointestinal side effects have included constipation, abdominal pain, biliary tract spasm, dry mouth, glossitis, and appetite abnormalities.
Other side effects have included increased sweating which has been common after chronic methadone use.
Hypersensitivity side effects to methadone are rare, and have included rash, pruritus, and edema.
One study has suggested that detoxification from methadone maintenance therapy may result in the development of an organic mood syndrome in many patients.
Psychiatric side effects have included psychological dependence. A case of obsessive compulsive symptoms precipitated by methadone tapering has been reported.
Endocrine side effects have included stimulation of thyroxine binding globulin (TBG), resulting in increased TBG, total T3 and T4, but unaltered free T3 and T4. Hyperprolactinemia has also been associated with methadone therapy.
Genitourinary side effects have included amenorrhea, antidiuretic effect, reduced libido and/or potency, urinary hesitancy, and urinary retention.
Respiratory side effects have included pulmonary edema, respiratory depression, and a blunted response to hypercarbia.
A case of rhabdomyolysis and subsequent acute renal failure following ingestion of large doses of methadone has been reported.
Hematologic side effects associated with methadone have included mild lymphocytosis and increased serum protein, albumin, and globulin.
General side effects including asthenia, edema, and headache have been reported.
Metabolic side effects including hypokalemia, hypomagnesemia, and weight gain have been reported.
Ocular side effects have included visual disturbances.
More about methadone
- Methadone concentrate
- Methadone dispersible tablets
- Methadone solution
- Methadone tablets for oral suspension
- Methadone (Advanced Reading)
Related treatment guides
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