Name of the CNS depressants-Synthetics narcotics Drugs
- Methaedone
- Mepheridine
1. Methaedone
| Methaedone |
| Availability Injection: 10 mg/ml Oral solution: 5 mg/5 ml, 10 mg/5 ml, 10 mg/ml (concentrate) Tablets: 5 mg, 10 mg Tablets (dispersible diskettes): 40 mg |
| Indications and dosages ➣ Opioid detoxification Adults: Initially, 15 to 20 mg/day P.O. to suppress withdrawal. Additional doses may be necessary if symptoms aren’t suppressed or if they reappear. Most patients are adequately stabilized on total daily dosage of 40 mg given in single or divided doses; however, some may need higher dosages. When patient is stable for 2 to 3 days, decrease dosage gradually at 2-day intervals. If patient can’t tolerate oral doses, give I.M. or subcutaneously (usually at about 25% of total daily P.O. dosage) in two injections. ➣ To maintain opioid abstinence Adults: Oral dosage highly individualized based on control of abstinence symptoms without respiratory depression or marked sedation. If patient can’t tolerate oral doses, give I.M. or subcutaneously (usually at about 25% of total daily P.O. dosage) in two injections. ➣ Chronic and severe pain Adults: For chronic pain, 2.5 to 10 mg P.O., I.M., or subcutaneously q 3 to 4 hours as needed; adjust dosage and dosing interval as needed. For severe chronic pain (as in terminal illness), 5 to 20 mg P.O. q 6 to 8 hours. Children: Dosage individualized |
Mechanism of Action
Binds with and activates opioid receptors (primarily mu receptors) in spinal cord and higher levels of CNS to produce analgesia and euphoric effects.
Pharmacokinetics
- Bioavailability: 36-100%
- Peak plasma time: 1-7.5 hr
- Protein bound: 85-90%
- Metabolized in liver via N-demethylation
- Half-life: 8-59 hr
- Excretion: Urine
Administration
- Mix dispersible tablets with 120 ml of water or orange juice, citrus Tang, or other acidic fruit beverage.
- Dilute 10 mg/ml of oral solution with water or other liquid to at least 30 ml. In detoxification and maintenance of opioid withdrawal, dilute solution in at least 90 ml of fluid.
- When used parenterally, I.M. route is preferred. Rotate injection sites.
- For detoxification and maintenance, give oral solution only, to reduce potential for parenteral abuse, hoarding, and accidental ingestion.
- Know that patients who can’t take oral drugs because of nausea or vomiting during detoxification or maintenance should be hospitalized and given methadone parenterally
Contraindications
- Hypersensitivity to drug or other opioid agonists
Precautions:
- Head trauma; severe renal, hepatic, or pulmonary disease; hypothyroidism; adrenal insufficiency; undiagnosed abdominal pain; prostatic hypertrophy; urethral stricture; toxic psychosis; Addison’s disease; cor pulmonale; increased intracranial pressure; severe inflammatory bowel disease; severe CNS depression; hypercapnia; seizures; fever; alcoholism
- Recent renal or hepatic surgery
- Elderly or debilitated patients
- Pregnant patients, patients in labor, or breastfeeding patients.
Adverse reactions
- CNS: amnesia, anxiety, confusion, poor concentration, delirium, delusions, depression, dizziness, drowsiness, euphoria, fever, hallucinations, headache, insomnia, lethargy, lightheadedness, malaise, psychosis, restlessness, sedation, clouded sensorium, syncope, tremor,seizures, coma
- CV: hypotension, palpitations, edema, bradycardia,shock, cardiac arrest
- EENT: visual disturbances
- GI: nausea, vomiting, constipation, ileus, biliary tract spasm, gastroesophageal reflux, indigestion, dysphagia, dry mouth, anorexia
- GU: urinary hesitancy, urinary retention, prolonged labor, difficult ejaculation, erectile dysfunction
- Hematologic: anemia, leukopenia, thrombocytopenia
- Musculoskeletal: joint pain
- Respiratory: depressed cough reflex, hypoventilation, wheezing, asthma exacerbation, atelectasis, pulmonary edema, bronchospasm, respiratory depression or arrest, apnea
- Skin: urticaria, pruritus, flushing, pallor, diaphoresis
- Other: allergic reaction, hiccups, facial or injection site edema, pain, physical or psychological drug dependence, withdrawal symptoms
Patient monitoring
- Assess patient for relief of severe, chronic pain requiring around-theclock dosing. Tailor dosage to patient’s pain level and drug tolerance.
- Monitor CNS, respiratory, and cardiovascular status.
- Watch for deepening sedation, which may increase with successive doses.
- Evaluate bowel and bladder function. Give laxatives if appropriate.
- Monitor detoxification treatment closely. Short-term detoxification shouldn’t exceed 30 days; long-term detoxification, 180 days.
- Assess patient on maintenance therapy for successful rehabilitation. Know that maintenance therapy should be part of comprehensive treatment plan that includes medical, vocational rehabilitative, employment, educational, and counseling services.
Patient teaching
- Instruct patient to promptly report severe adverse reactions.
- Tell patient he may take drug with food if GI upset occurs.
- Tell ambulatory patient to change positions slowly to avoid orthostatic hypotension.
- Caution patient not to discontinue drug abruptly.
- Advise patient to avoid driving and other hazardous activities, because drug may cause drowsiness or dizziness.
- Tell female patient to inform prescriber if she’s pregnant or breastfeeding.
- As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.
Nursing Considerations
- Before giving methadone, make sure opioid antagonist and equipment for administering oxygen and controlling respiration are nearby.
- Before therapy begins, assess patient’s current drug use, including all prescription and OTC drugs
- Dilute oral concentrate with water or another liquid to volume of at least 30 ml, but preferably to 90 ml or more, before administration. Dissolve dispersible tablets in water or another liquid before giving.
- Monitor patient for expected excessive drowsiness, unsteadiness, or confusion during first 3 to 5 days of therapy, and notify prescriber if effects continue to worsen or persist beyond this time
- Watch for drug tolerance, especially in patients with a history of chronic drug abuse, because methadone can cause physical and psychological dependence.
- Monitor patient for pain because maintenance dosage doesn’t provide pain relief; patients with tolerance to opiate agonists, including those with chronic cancer pain, may require a higher dosage.
- Monitor patients who are pregnant or who have liver or renal impairment for increased adverse effects from methadone because drug may have a prolonged duration and cumulative effect in these patients. Methadone may prolong labor by reducing strength, duration, and frequency of uterine contractions, so expect dosage to be tapered before third trimester of pregnancy. Breast-feeding mothers on maintenance therapy put their infants at risk of withdrawal symptoms if they abruptly stop breast-feeding or discontinue methadone therapy. Methadone also accumulates in CNS tissue, increasing the risk of seizures in infants.
- Check plasma amylase and lipase levels in patients who develop biliary tract spasms because levels may increase up to 15 times normal. Notify prescriber immediately of any significant or sustained increase.
- Monitor patients who have head injuries or other conditions that may increase intracranial pressure (ICP) because methadone may further increase ICP.
- Assess patient for withdrawal symptoms and tolerance to therapy because physiologic dependence can occur with longterm methadone use. Avoid abrupt discontinuation because withdrawal symptoms will occur within 3 to 4 days after last dose.
- Monitor patients, especially the elderly, for cardiac arrhythmias, hypotension, hypovolemia, orthostatic hypotension, and vasovagal syncope because methadone may produce cholinergic effects in patients with cardiac disease, resulting in bradycardia and peripheral vasodilation; dosage decrease may be indicated.
- Monitor patients with prostatic hypertrophy, urethral stricture, or renal disease for urine retention and oliguria because methadone can increase tension of detrusor muscle.
- Be prepared to treat patient’s symptoms of anxiety, and be aware that anxiety may be confused with symptoms of opioid abstinence and that methadone doesn’t have antianxiety effects.
2.Mepheridine
| Mepheridine |
| Availability Injection: 10 mg/ml, 25 mg/ml, 50 mg/ ml, 75 mg/ml, 100 mg/ml Oral solution: 500 mg/5 ml Syrup: 50 mg/5 ml Tablets: 50 mg, 100 mg |
| Indications and dosages ➣ Moderate to severe pain Adults: 50 to 150 mg P.O., I.M., or subcutaneously q 3 to 4 hours as needed Children: 1.1 to 1.8 mg/kg P.O., I.M., or subcutaneously q 3 to 4 hours, not to exceed 100 mg/dose ➣ Preoperative sedation Adults: 50 to 100 mg I.M. or subcutaneously 30 to 90 minutes before anesthesia Children: 1 to 2.2 mg/kg I.M. or subcutaneously 30 to 90 minutes before anesthesia. Don’t exceed adult dosage. ➣ Support of anesthesia Adults: Fractional doses (such as 10 mg/ml) by repeated slow I.V. injections or continuous I.V. infusion of a more dilute solution (such as 1 mg/ml). Dosages should be individualized. ➣ Analgesia during labor Adults: 50 to 100 mg I.M. or subcutaneously when contractions are regular. May repeat q 1 to 3 hours. |
Mechanism of Action
Binds with opiate receptors in the spinal cord and higher levels of the CNS. In this way, meperidine stimulates mu and kappa receptors, which alters the perception of and emotional response to pain.
Pharmacokinetics
- Bioavailability: 50-60%; hepatic impairment, 80-90%
- Peak plasma time: SC, 40-60 min; IM, 30-50 min
- Protein bound: 65-75%
- Metabolized in liver via hydrolysis, partial conjugation with glucuronic acid, N-demethylation
- Half-life: 2.5-4 hr (adults); 7-11 hr (liver disease)
- Excretion: Urine (primarily)
Administration
- Give I.M. injection slowly into large muscle. Preferably, use diluted solution.
- Give oral solution or syrup in a half glass of water to avoid topical anaesthetic effect on mucous membranes.
- Be aware that drug is compatible with 5% dextrose and lactated Ringer’s solution, dextrose-saline solution combinations, and 2.5%, 5%, or 10% dextrose in water. 2Know that drug is not compatible with soluble barbiturates, aminophylline, heparin, morphine sulfate, methicillin, phenytoin, sodium bicarbonate, iodide, sulfadiazine, or sulfisoxazole.
- Don’t give for chronic pain control, because of potential toxicity and dependence
Contraindications
- Hypersensitivity to drug or bisulfites (with some injectable products)
- MAO inhibitor use within past 14 days
Precautions:
- Head trauma; increased intracranial pressure (ICP); severe renal, hepatic, or pulmonary disease; hypothyroidism; adrenal insufficiency; extensive burns; alcoholism; supraventricular tachycardia; seizure disorders
- Undiagnosed abdominal pain or prostatic hyperplasia
- Elderly or debilitated patients
- Pregnant patients (not recommended before labor)
- Labor (drug may cause respiratory depression in neonate)
- Breastfeeding patients
- Children.
Adverse reactions
- CNS: confusion, sedation, dysphoria, euphoria, floating feeling, hallucinations, headache, unusual dreams, seizures
- CV: hypotension, bradycardia, cardiac arrest, shock
- EENT: blurred vision, diplopia, miosis
- GI: nausea, vomiting, constipation, ileus, biliary tract spasms
- GU: urinary retention Respiratory: respiratory depression, respiratory arrest
- Skin: flushing, sweating, induration
- Other: pain at injection site, local irritation, physical or psychological drug dependence, drug tolerance
Patient monitoring
- Monitor vital signs. Don’t give drug if patient has significant respiratory or CNS depression.
- Reassess patient’s pain level after administration. 2Watch for seizures, agitation, irritability, nervousness, tremors, twitches, and myoclonus in patients at risk for normeperidine accumulation (such as those with renal or hepatic impairment).
- Use with extreme caution in patients with head injury. Drug may increase ICP and cause adverse reactions that obscure clinical course.
- Closely monitor patients with acute abdominal pain. Drug may obscure diagnosis and clinical course of GI condition.
- Evaluate bowel and bladder function.
- With long-term or repeated use, watch for psychological and physical drug dependence and tolerance.
- With pediatric patients, stay alert for increased risk of seizures.
Patient teaching
- Tell patient using oral solution or syrup to take drug with a half-glass of water to minimize local anesthetic effect.
- Caution patient to avoid driving and other hazardous activities, because drug may cause dizziness or drowsiness.
- Advise patient to avoid alcohol.
- Instruct ambulatory patient to change position slowly to avoid orthostatic hypotension.
- Tell female patient to inform prescriber if she is pregnant or breastfeeding.
- As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.
Nursing Considerations
- Use meperidine with extreme caution in patients with acute abdominal conditions, hepatic or renal disorders, hypothyroidism, prostatic hyperplasia, seizures, or supraventricular tachycardia.
- To minimize local anesthetic effect, dilute meperidine syrup with water before use.
- Give I.V. dose slowly by direct injection or as a slow continuous infusion. Mix with D5W, normal saline solution, or Ringer’s or lactated Ringer’s solution.
- Keep naloxone available when giving I.V. meperidine.
- Be aware that subcutaneous injection is painful and isn’t recommended.
- Be aware that oral form of meperidine is less than half as effective as parenteral meperidine. Give I.M. form when possible, and expect to increase dosage when switching patient to oral form.
- Monitor patient’s respiratory and cardiovascular status during treatment. Notify prescriber immediately and expect to discontinue drug if respiratory rate falls to less than 12 breaths/minute or if respiratory depth decreases.
- Monitor patient’s bowel function to detect constipation and assess the need for stool softeners.
- Assess for signs of physical dependence and abuse.
- Expect withdrawal symptoms to occur if drug is abruptly withdrawn after longterm use
REFERENCES
- Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
- McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
- April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
- Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
- Nursebro.com, Search – Nursebro
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