Pethin

Adults:

Adult Dosage: Analgesia: Dosage should be adjusted according to the severity of pain and the response of the patient and also depends on patient profile eg: age, weight, sex, previous exposure to narcotics. 25 to 100 mg by IM (preferred) or S.C. injection, every 3 to 4 hours. 25 to 50 mg slow IV injection, every 3 to 4 hours  Usual dose is 200 mg/day by the IV route. Intravenous injection should be made very slowly, preferably using a diluted solution. For continuous intravenous infusion adequate analgesia should be established prior to commencement of the infusion. A dosage of 0.3 mg/kg/hr is recommended as the initial intravenous infusion rate. Clinical experience suggests that patients with normal renal function receiving more than 1000 mg/24 hrs pethidine are at particular risk of developing pethidine associated neurotoxicity (PAN). Patients receiving over 800 mg/24 hrs pethidine should usually be monitored for early signs of norpethidine toxicity Obstetric Analgesia: 50 to 100 mg by IM (preferred) or S.C. injection, administered when pain becomes regular. May be repeated 3 to 4 times at one to three hour intervals if necessary. Maximum of 4 doses in 24 hoursAnaesthesia Adjunct: As premedication, intramuscular (preferred) or subcutaneous, 50 to 100 mg thirty to ninety minutes prior to anaesthesia. As an adjunct to anaesthesia, intravenous, by repeated slow injection of fractional doses of a solution diluted to 10 mg per mL. Dosage by this route should not exceed 25 to 50 mg. Dosage must be titrated to the needs of the patient, depending on the premedication given, the type of anaesthesia, and the nature and duration of the surgical procedure.Patient-Controlled Analgesia: Patient-controlled analgesia (PCA) allows patients to assess their own level of pain and consequently titrate the amount of pethidine they require for adequate pain control against sedation and other side effects. Adequate analgesia should be established prior to commencement of PCA. The dosages and time intervals are preset into a microprocessor-controlled infusion pump. When the patient experiences pain, a button is depressed by the patient and a dose of pethidine is administered intravenously. If the patient should depress the button before the preset time interval (lockout interval) has elapsed, no extra drug is administered. For adults, demand doses, of 5 mg to a maximum of 20 mg pethidine have been given via PCA using a lockout interval of 6 to 20 minutes. Along with the self-administered dose of pethidine, some syringe pumps also deliver a background continuous infusion of pethidine at a basal rate. Some PCA pumps allow a maximum dosage over a defined period to be preset in order to avoid patient overdosage. The demand dosage and lockout interval should be determined according to the patient’s analgesic requirements. Patients receiving a background infusion of pethidine should generally receive a smaller demand dose relative to equivalent patients utilising a demand dose only. Clinical experience suggests that patients with normal renal function receiving more than 1000 mg/24hrs pethidine are at particular risk of developing pethidine associated neurotoxicity (PAN). Patients receiving over 800 mg/24hrs pethidine should usually be monitored for early signs of norpethidine toxicity. Pethidine-associated neurotoxicity is dose related, so pethidine should not be used for periods greater than 24 to 36 hours Paediatric Dose: Analgesia: Intramuscular (preferred) or subcutaneous, 0.5 to 2 mg per kg of body weight, not to exceed 100 mg, every three to four hours as needed. Preoperative: Intramuscular (preferred) or subcutaneous, 1 to 2 mg per kg of body weight, not to exceed 100 mg, thirty to ninety minutes prior to anaesthesia. Neonates: Excretion and metabolism of pethidine in the neonate is reduced compared with adults. Safety has not been established in neonates and due to lack of data, no dosage regimen can be recommended.