meperidine hydrochloride (pethidine)

(me per' i deen)



Pregnancy Category C

Controlled Substance C-II


Drug class

Opioid agonist analgesic


Therapeutic actions

Acts as agonist at specific opioid receptors in the CNS to produce analgesia, euphoria, sedation; the receptors mediating these effects are thought to be the same as those mediating the effects of endogenous opioids (enkephalins, endorphins).



        Oral, parenteral: Relief of moderate to severe acute pain

        Parenteral: Preoperative medication, support of anesthesia, and obstetric analgesia


Contraindications and cautions

        Contraindicated with hypersensitivity to opioids, diarrhea caused by poisoning (before toxins are eliminated), bronchial asthma, COPD, cor pulmonale, respiratory depression, anoxia, kyphoscoliosis, acute alcoholism, increased intracranial pressure, pregnancy, seizure disorder, renal dysfunction. Contraindicated in premature infants.

        Use cautiously with acute abdominal conditions, CV disease, supraventricular tachycardias, myxedema, delirium tremens, cerebral arteriosclerosis, ulcerative colitis, fever, Addison's disease, prostatic hypertrophy, urethral stricture, recent GI or GU surgery, toxic psychosis, labor or delivery (opioids given to the mother can cause respiratory depression of neonate; premature infants are especially at risk), renal or hepatic dysfunction, lactation.


Available forms

Tablets—50, 100 mg; syrup—50 mg/mL; injection—25, 50, 75, 100 mg/mL




        Relief of pain: Individualize dosage; 50–150 mg IM, subcutaneously, or PO q 3–4 hr as needed. Diluted solution may be given by slow IV injection. IM route is preferred for repeated injections.

        Preoperative medication: 50–100 mg IM or subcutaneously, 30–90 min before beginning anesthesia.

        Support of anesthesia: Dilute to 10 mg/mL, and give repeated doses by slow IV injection, or dilute to 1 mg/mL and infuse continuously. Individualize dosage.

        Obstetric analgesia: When contractions become regular 50–100 mg IM or subcutaneously; repeat q 1–3 hr.


Contraindicated in premature infants.

        Relief of pain: 1.1–1.75 mg/kg IM, subcutaneously, or PO up to adult dose q 3–4 hr as needed.

        Preoperative medication: 1.1–2.2 mg/kg IM or subcutaneously, up to adult dose, 30–90 min before beginning anesthesia.


Use caution; respiratory depression may occur in elderly, the very ill, those with respiratory problems. Reduced dosage may be needed.








15 min

60 min

2–4 hr


10–15 min

30–60 min

2–4 hr



5–7 min

2–4 hr


Metabolism: Hepatic; T1/2: 3–8 hr

Distribution: Crosses placenta; enters breast milk

Excretion: Urine


IV facts

Preparation: Dilute parenteral solution prior to IV injection using 5% dextrose and lactated Ringer's; dextrose-saline combinations; 2.5%, 5%, or 10% dextrose in water, Ringer's, or lactated Ringer's; 0.45% or 0.9% sodium chloride; 1/6 molar sodium lactate.

Infusion: Administer by slow IV injection over 4–5 min or by continuous infusion when diluted to 1 mg/mL.

WARNING: Incompatibilities: Do not mix meperidine solutions with solutions of barbiturates, aminophylline, heparin, morphine sulfate, methicillin, phenytoin, sodium bicarbonate, iodide, sulfadiazine, sulfisoxazole.

Y-site incompatibilities: Do not give with cefoperazone, mezlocillin, minocycline, tetracycline.


Adverse effects

        CNS: Light-headedness, dizziness, sedation, euphoria, dysphoria, delirium, insomnia, agitation, anxiety, fear, hallucinations, disorientation, drowsiness, lethargy, impaired mental and physical performance, coma, mood changes, weakness, headache, tremor, seizures, miosis, visual disturbances, suppression of cough reflex

        CV: Facial flushing, peripheral circulatory collapse, tachycardia, bradycardia, arrhythmia, palpitations, chest wall rigidity, hypertension, hypotension, orthostatic hypotension, syncope

        Dermatologic: Pruritus, urticaria, laryngospasm, bronchospasm, edema

        GI: Nausea, vomiting, dry mouth, anorexia, constipation, biliary tract spasm, increased colonic motility in patients with chronic ulcerative colitis

        GU: Ureteral spasm, spasm of vesical sphincters, urinary retention or hesitancy, oliguria, antidiuretic effect, reduced libido or potency

        Local: Tissue irritation and induration (subcutaneous injection)

        Major hazards: Respiratory depression, apnea, circulatory depression, respiratory arrest, shock, cardiac arrest

        Other: Sweating, physical tolerance and dependence, psychological dependence



        Potentiation of effects with barbiturate anesthetics; decrease dose of meperidine when coadministering

        WARNING: Severe and sometimes fatal reactions (resembling opioid overdose; characterized by seizures, hypertension, hyperpyrexia) when given to patients receiving or who have recently received MAOIs; do not give meperidine to patients on MAOIs

        Increased likelihood of respiratory depression, hypotension, profound sedation, or coma with phenothiazines

        Elevated biliary tract pressure may cause increases in plasma amylase, lipase; determinations of these levels may be unreliable for 24 hr after administration of opioids


Nursing considerations


        History: Hypersensitivity to opioids, diarrhea caused by poisoning, bronchial asthma, COPD, cor pulmonale, respiratory depression, anoxia, kyphoscoliosis, acute alcoholism, increased intracranial pressure; acute abdominal conditions, CV disease, supraventricular tachycardias, myxedema, seizure disorders, delirium tremens, cerebral arteriosclerosis, ulcerative colitis, fever, Addison's disease, prostatic hypertrophy, urethral stricture, recent GI or GU surgery, toxic psychosis, renal or hepatic dysfunction, pregnancy, lactation

        Physical: T; skin color, texture, lesions; orientation, reflexes, bilateral grip strength, affect, pupil size; P, auscultation, BP, orthostatic BP, perfusion; R, adventitious sounds; bowel sounds, normal output; frequency and pattern of voiding, normal output; ECG; EEG; thyroid, liver, kidney function tests



        Administer to lactating women 4–6 hr before the next feeding to minimize the amount in milk.

        WARNING: Keep opioid antagonist and facilities for assisted or controlled respiration readily available during parenteral administration.

        WARNING: Use caution when injecting subcutaneously into chilled areas of the body or in patients with hypotension or in shock; impaired perfusion may delay absorption; with repeated doses, an excessive amount may be absorbed when circulation is restored.

        Reduce dosage of meperidine by 25%–50% in patients receiving phenothiazines or other tranquilizers.

        Give each dose of the oral syrup in half glass of water. If taken undiluted, it may exert a slight local anesthetic effect on mucous membranes.

        Reassure patient that addiction is unlikely; most patients who receive opiates for medical reasons do not develop dependence syndromes.

        WARNING: Use meperidine with extreme caution in patients with renal dysfunction or those requiring repeated dosing due to accumulation of normeperidine, a toxic metabolite that may cause seizures.


Teaching points

        Take drug exactly as prescribed.

        Avoid alcohol, antihistamines, sedatives, tranquilizers, OTC drugs.

        Do not take leftover medication for other disorders, and do not let anyone else take this prescription.

        You may experience these side effects: Nausea, loss of appetite (take with food and lie quietly, eat frequent small meals); constipation (request a laxative); dizziness, sedation, drowsiness, impaired visual acuity (avoid driving, performing other tasks that require alertness, visual acuity).

        Report severe nausea, vomiting, constipation, shortness of breath, or difficulty breathing.


Adverse effects in Italic are most common; those in Bold are life-threatening.