Methadose

methadone

Dolophine

Metadol

Methadose

Indications

Action

Pharmacokinetics

Time/action profile (analgesic effect)

Contraindications/Precautions

Adverse Reactions/Side Effects

Central nervous system

• confusion (most frequent)
• sedation (most frequent)
• dizziness
• dysphoria
• euphoria
• floating feeling
• hallucinations
• headache
• unusual dreams

Ear, Eye, Nose, Throat

• blurred vision
• diplopia
• miosis

Respiratory

• respiratory depression

Cardiovascular

• torsades de pointes (life-threatening)
• hypotension (most frequent)
• bradycardia
• QT interval prolongation

Gastrointestinal

• constipation (most frequent)
• nausea
• vomiting

Genitourinary

• urinary retention

Dermatologic

• flushing
• sweating

Miscellaneous

• physical dependence
• psychological dependence
• tolerance

Interactions

Drug-Drug interaction

Route/Dosage

Availability (generic available)

Nursing implications

Nursing assessment

• Pain: Assess type, location, and intensity of pain prior to and 1–2 hr (peak) following administration. When titrating opioid doses, increases of 25–50% should be administered until there is either a 50% reduction in the patient’s pain rating on a numeric or visual analogue scale or the patient reports satisfactory pain relief. A repeat dose can be safely administered at the time of the peak if previous dose is ineffective and side effects are minimal. Cumulative effects of this medication may require periodic dose adjustments.
  • Doses of methadone for patients on methadone maintenance only prevent withdrawal symptoms; no analgesia is provided. Additional opioid doses are required for treatment of pain.
• An equianalgesic chart (see ) should be used when changing routes or when changing from one opioid to another.
• Assess BP, pulse, and respirations before and periodically during administration. If respiratory rate is < 10/min, assess level of sedation. Dose may need to be decreased by 25–50%. Initial drowsiness will diminish with continued use.
• Assess bowel function routinely. Prevention of constipation should be instituted with increased intake of fluids and bulk and with laxatives to minimize constipating effects. Stimulant laxatives should be administered routinely if opioid use exceeds 2–3 days, unless contraindicated.
• Prolonged use may lead to physical and psychological dependence and tolerance. This should not prevent patient from receiving adequate analgesia. Most patients who receive methadone for pain do not develop psychological dependence. Progressively higher doses may be required to relieve pain with long-term therapy.
• Assess for history of structural heart disease, arrhythmia, and syncope. Obtain a pretreatment ECG to measure QTc interval and follow-up ECG within 30 days and annually. Additional ECGs recommended if dose >100 mg/day or if patients have unexplained syncope or seizures. If QTc interval is >450 ms but <500 ms, discuss potential risks and benefits with patients and monitor more frequently. If the QTc interval >500 ms, consider discontinuing or reducing dose; eliminating contributing factors (drugs that promote hypokalemia) or using an alternative therapy.
• Opioid Detoxification: Assess patient for signs of opioid withdrawal (irritability, runny nose and eyes, abdominal cramps, body aches, sweating, loss of appetite, shivering, unusually large pupils, trouble sleeping, weakness, yawning). Methadone maintenance is undertaken only by federally approved treatment centers. This does not preclude maintenance for addicts hospitalized for other conditions and who require temporary maintenance during their care.
• Lab Test Considerations: May ↑ plasma amylase and lipase levels.
If an opioid antagonist is required to reverse respiratory depression or coma, naloxone is the antidote. Dilute the 0.4-mg ampule of naloxone in 10 mL of 0.9% NaCl and administer 0.5 mL (0.02 mg) by direct IV push every 2 min. For children and patients weighing < 40 kg, dilute 0.1 mg of naloxone in 10 mL of 0.9% NaCl for a concentration of 10 mcg/mL and administer 0.5 mcg/kg every 2 min. Titrate dose to avoid withdrawal, seizures, and severe pain.

Potential Nursing Diagnoses

Implementation

• high alert: Accidental overdose of opioid analgesics has resulted in fatalities. Before administering, clarify all ambiguous orders; have second practitioner independently check original order and dose calculations.
• Do not confuse methadone with dexmethylphenidate, ketorolac, Mephyton (phytonadione), Metadate ER/CD (methylphenidate), or methylphenidate.
• Explain therapeutic value of medication prior to administration to enhance the analgesic effect.
  • Regularly administered doses may be more effective than prn administration. Analgesic is more effective if administered before pain becomes severe. For patients in chronic severe pain, the oral solution containing 5 or 10 mg/5 mL is recommended on a fixed dose schedule.
  • Coadministration with nonopioid analgesics may have additive analgesic effects and may permit lower doses.
  • Medication should be discontinued gradually after long-term use to prevent withdrawal symptoms.
• Oral: Doses may be administered with food or milk to minimize GI irritation.
  • Dilute each dose of 10 mg/mL oral concentrate with at least 30 mL of water or other liquid prior to administration.
  • Diskettes (dispersible tablets) are to be dissolved and used for detoxification and maintenance treatment only. Available only to licensed detoxification/maintenance programs.
• Subcutaneous: Intramuscular: IM is the preferred parenteral route for repeated doses. Subcut administration may cause tissue irritation.

Patient/Family Teaching

• Instruct patient on how and when to ask for and take pain medication.
• Instruct patient to take methadone exactly as directed. If dose is less effective after a few weeks, do not increase dose without consulting health care professional.
• May cause drowsiness or dizziness. Advise patient to call for assistance when ambulating or smoking and to avoid driving or other activities requiring alertness until response to medication is known.
• Inform patient of the potential for arrhythmias and emphasize the importance of regular ECGs.
• Caution patient to notify health care professional if signs of overdose (difficult or shallow breathing, extreme tiredness or sleepiness, blurred vision, inability to think, talk, or walk normally, and feelings of faintness, dizziness, or confusion) occur. Methadone has a prolonged action causing increased risk of overdose.
• Advise patient to change positions slowly to minimize orthostatic hypotension.
• Advise patient to tell health care professional what medications they are taking and to avoid taking new Rx, OTC, vitamins, or herbal products without consulting health care professional. Caution patient to avoid concurrent use of alcohol or other CNS depressants with this medication.
• Encourage patient to turn, cough, and breathe deeply every 2 hr to prevent atelectasis.

Evaluation/Desired Outcomes

• Decrease in severity of pain without a significant alteration in level of consciousness or respiratory status.
• Prevention of withdrawal symptoms in detoxification from heroin and other opioid analgesics.