A-Z Drug Facts > Methadone Hydrochloride

Methadone Hydrochloride

Pronouncation: (METH-uh-dohn HIGH-droe-KLOR-ide)
Class: Opioid analgesic

Trade Names:
Dolophine Hydrochloride
- Tablets 5 mg
- Tablets 10 mg
- Injection 10 mg/mL

Trade Names:
Methadose
- Tablets 5 mg
- Tablets 10 mg
- Tablets, dispersible 40 mg
- Concentrate, oral 10 mg/mL

Metadol (Canada)

Pharmacology

Feedback for Methadone Hydrochloride As a treatment for... Avg User Ratings [?] Opiate Withdrawal 9.4 17 comments  Rate it! Pain 8.3 21 comments  Rate it! Compare with other drugs.

Relieves pain by stimulating opiate receptors in CNS; also causes respiratory depression, peripheral vasodilation, inhibition of intestinal peristalsis, sphincter of Oddi spasm, stimulation of chemoreceptors that cause vomiting and increased bladder tone.

Pharmacokinetics

Distribution

Protein binding is high.

Metabolism

Methadone is metabolized hepatically and in intestinal mucosa.

Elimination

The primary route for elimination is renal; minor route is biliary. The t _½ is 15 to 30 h (repeated dosing).

Onset

Onsets of action are 30 to 60 min (oral) and 10 to 20 min (IM).

Peak

Times to peak effect are 90 to 120 min (oral), 60 to 120 min (IM), and 15 to 30 min (IV).

Duration

Durations are 4 to 6 h (repeated oral dosing), 4 to 5 h (IM). and 3 to 4 h (IV).

Indications and Usage

Management of severe pain; detoxification and temporary maintenance treatment of narcotic addiction.

Contraindications

Standard considerations.

Dosage and Administration

Pain
Adults

IM/SC/PO 2.5 to 10 mg every 3 to 4 h as needed. May need higher doses in patients with severe pain or tolerance.

Detoxification
Adults

PO 15 to 20 mg initially to suppress withdrawal symptoms. Additional doses may be needed.

Patients Physically Dependent on High Doses of Narcotics

PO 40 mg/day may be given for 2 to 3 days; decrease dose every 1 to 2 days.

Maintenance

PO 20 to 40 mg initially to suppress withdrawal symptoms in patients who are heavy heroin users. Additional 10 mg doses can be given as needed. Adjust dose as tolerated and required, up to 120 mg/day.

Storage/Stability

Store at room temperature (59° to 86°F) in light-resistant container.

Drug Interactions

Barbiturate anesthetics

Drug actions may be additive.

Cimetidine, protease inhibitors

Monitor for increased respiratory and CNS depression.

CNS depressants (eg, tranquilizers, sedatives, alcohol)

Additive CNS depression.

Fluvoxamine

Monitor for increased CNS depression when taken with methadone. Monitor for signs and symptoms of withdrawal when fluvoxamine is discontinued.

Hydantoins, rifampin, barbiturates

May decrease effectiveness of methadone.

Urinary acidifiers

May increase renal clearance of methadone.

Laboratory Test Interactions

Increased amylase and lipase may occur up to 24 h after dose.

Adverse Reactions

Cardiovascular

Hypotension; palpitations; bradycardia; tachycardia.

CNS

Lightheadedness; euphoria; dysphoria; headache; insomnia; dizziness; sedation; disorientation; incoordination.

Dermatologic

Sweating; pruritus; urticaria.

GI

Nausea; vomiting; constipation; abdominal pain; dry mouth.

Genitourinary

Urinary retention or hesitancy.

Hematologic

Thrombocytopenia.

Respiratory

Laryngospasm; depression of cough reflex.

Miscellaneous

Tolerance; psychological and physical dependence with chronic use.

Precautions

Warnings Use in withdrawal syndromes must be dispensed by approved pharmacy/maintenance programs. Avoid use of narcotic antagonist as it may precipitate an acute withdrawal syndrome.

Pregnancy

Pregnancy category undetermined. Methadone use has been associated with low infant birthweight.

Lactation

Excreted in breast milk.

Children

Not recommended for children; dosage is not well defined.

Renal Function

May need to decrease dose in patients with renal function impairment.

Hepatic Function

May need to decrease dose in patients with hepatic impairment.

Special Risk Patients

Use drug with caution in patients with myxedema, acute alcoholism, acute abdominal conditions, ulcerative colitis, decreased respiratory reserve, head injury or increased intracranial pressure, hypoxia, supraventricular tachycardia, depleted blood volume or circulatory shock.

Drug dependence

Methadone has abuse potential.

Obstetrical analgesia

Do not use methadone for obstetrical analgesia. Its long duration of action increases the probability of neonatal respiratory depression.

Treatment of drug addiction

Methadone for detoxification should not be given for more than 21 days and treatment should not be repeated within 4 wk. More than 3 wk in methadone treatment of narcotic dependence is considered maintenance therapy; only approved programs can provide this therapy.

Overdosage

Symptoms

Miosis, respiratory and CNS depression, cool/clammy skin, skeletal muscle flaccidity, circulatory collapse, seizures, cardiopulmonary arrest, apnea, hypotension, coma, death.

Patient Information

• Tell patient to take methadone regularly, as prescribed. If dose is missed, tell patient to take as soon as possible. If close to next dose, wait and take next regularly scheduled dose.
• Advise patient that drug may cause dizziness, drowsiness, or blurred vision and to use caution while driving or performing other hazardous tasks.
• Caution patient to avoid intake of alcoholic beverages or other CNS depressants.
• If constipation occurs, tell patient to increase fluids and fiber or to use fiber laxative.
• Explain that use of methadone before pain becomes acute will allow it to alleviate pain better.
• Caution patient to avoid sudden position changes to prevent orthostatic hypotension.
• Explain types and potential significance of sympathomimetic side effects.

Link to this page

Printable Version

Email Page

Add to my drug list