Contents

Paracetamol

Indication

Suspension: For the reduction of fever.For the temporary relief of minor aches and pains including headache, toothache, muscular ache, backache, and aches and pains associated with flu.Injection: Useful in conditions where a rapid predictable blood level is required as in high grade fever in children predisposed to febrile convulsions.High grade fever in patients who cannot tolerate oral medications.As an analgesic, in postoperative patients where oral medication is not possible.

Dosage / Direction For Use

Susp 120 mg/5 mL Childn 7-12 yr 2-3 tsp, 3-6 yr 1-2 tsp, 1-2 yr 1 tsp. 250 mg/5 mL Childn 7-12 yr 1-1½ tsp, 3-6 yr ½-1 tsp, 1-2 yr ½ tsp. Drops Childn 1-2 yr 1-1.2 mL. Infant 7 mth-<1 yr 1 mL, 4-6 mth 0.6-1 mL, 0-3 mth 0.3-0.6 mL. All oral doses should be given 4 hrly. Inj 150 mg/mL Based in 10 mg/kg body wt/day, given via slow IV push or deep IM inj, every 4-6 hr/day. Adult 2-4 mL. Childn 7-12 yr 1.25-2 mL, 3-6 yr 1-1.25 mL, 1-2 yr 0.75-1 mL, 6-12 mth 0.5-0.75 mL, <6 mth 0.25-0.5 mL. May be given while symptoms persist, but not to exceed 5 doses in each 24-hr period for not >5 days unless directed by a physician.

Overdosage

Paracetamol in massive overdosage may cause hepatic toxicity in some patients. In adults and children older than 12 years, hepatic toxicity may occur following ingestion of greater than 7.5 to 10g over a period of 8 hours or less. Fatalities are infrequent (less than 3-4% of untreated cases) and have rarely been reported with overdoses of less than 15 grams. In children less than 12 years old, an acute overdosage with a paracetamol dose of less than 150 mg/kg body weight has not been associated with hepatic toxicity. Early symptoms following a potentially hepatotoxic overdose may include: nausea, vomiting, diaphoresis, and general malaise.Clinical and laboratory evidence of hepatic toxicity may not be apparent until 48 to 72 hours after ingestion. In adults and children over 12 years, any individual presenting with an unknown amount of paracetamol ingested or with a questionable or unreliable history about the time of ingestion should have a plasma paracetamol level drawn and be treated with N-acetylcysteine. Do not await results of assays for plasma paracetamol levels before initiating treatment with N-acetylcysteine. A plasma paracetamol assay should be obtained as early as possible, but no sooner than four hours following ingestion. Liver function studies should be obtained initially and repeated at 24-hour intervals.Serious toxicity or fatalities have been extremely infrequent following acute paracetamol overdose in young children, possibly because of differences in the way they metabolize paracetamol. In children, the maximum potential amount ingested can be more easily estimated. If more than 150 mg/kg or an unknown amount of paracetamol was ingested, obtain a plasma paracetamol level as soon as possible, but not sooner than four hours following ingestion. If an assay cannot be obtained and the estimated paracetamol ingestion exceeds 150 mg/kg, dosing with N-acetylcysteine should be initiated and continued for a full course of therapy.Suspension: The following additional procedures are recommended. Promptly initiate gastric decontamination of the stomach.

Administration

May be taken with or without food.

Contraindication

–

Special Precaution

Suspension: Paracetamol should be given with care to patients with impaired kidney function.Injection: Administer with caution in patients with preexisting anemia since cyanosis may not be apparent despite dangerously high blood methemoglobin concentrations.Administration to patients with renal or hepatic impairment may result in accumulation of hepatotoxic conjugates.

Adverse Reactions

Paracetamol very rarely aggravates bronchospasm in patients who are sensitive to aspirin and other non-steroidal anti-inflammatory drugs. Although paracetamol does not normally produce methemoglobinemia or hemolysis even after overdosage or in patients with glucose-6-phosphate dehydrogenase deficiency, there have been isolated reports of these complications.Suspension: Paracetamol, when taken within therapeutic levels, have low incidence of side effects. Skin rashes and minor gastrointestinal disturbances have been reported.Injection: Paracetamol has low incidence of side effects when used within therapeutic doses. Minor gastrointestinal disturbances have been reported. Dermatologic reactions like pruritic maculopapular rash and urticaria have been reported. Other sensitivity reactions including laryngeal edema, angioedema and anaphylactoid reactions may occur rarely.Hepatotoxicity can occur after ingestion of a single toxic dose or multiple excessive doses of paracetamol. Substantial elevations in alanine aminotransferase (ALT) occurred after receiving paracetamol in a dosage of 4g daily for two weeks.Prolonged administration of large doses of paracetamol may lead to thrombocytopenia, leukopenia, agranulocytosis, and pancytopenia. Physical dependence does not develop even with prolonged use.

Drug Interaction

Susp/Drops: Alcohol, anticoagulants, phenobarb, aspirin, chloramphenicol, desipramine, doxorubicin. Inj: Phenothiazine & other antipyretic therapy.

Storage

Store at temperatures not exceeding 30°C.Suspension: Protect from light.

Description

uspension: Each mL Naprex Suspension (Oral Drops) contains: Paracetamol 100 mg (Alcohol free).Each 5 mL (1 teaspoonful) Naprex Suspension contains: Paracetamol 120 mg (Alcohol free).Each 5 mL (1 teaspoonful) Naprex 250 Suspension contains: Paracetamol 250 mg (Alcohol free).This good tasting paracetamol suspension uses the TasteRite technology of PediaTech which significantly reduces the bitterness of medicine. This pleasant-tasting formulation allows easy administration of paracetamol especially in children.Injection: Each mL contains Paracetamol 150 mg.Paracetamol (Naprex) 150 mg/mL Solution for Injection (IM/IV) (300 mg/2 mL Injection) is free from extraneous matter, filled in a 2 mL amber ampule with white dot.

Action

Pharmacology: Pharmacodynamics: Mechanism of Action: Paracetamol exhibits analgesic and antipyretic activity by inhibiting prostaglandin synthesis. It produces analgesia by elevating the pain threshold and antipyresis through its action on the hypothalamic heat-regulating center.In therapeutic doses, the analgesic and antipyretic action of paracetamol is comparable to that of aspirin. Paracetamol dose not adversely affect platelet function and hemostasis.Pharmacokinetics: Suspension: Paracetamol is rapidly and completely absorbed after oral administration. Peak Plasma concentrations occur between 15 minutes to two hours after ingestion. The absolute oral bioavailability of paracetamol is about 80% and is independent of dose in the range of 5 to 20 mg/kg.Paracetamol is not bound to plasma proteins to any extent. The concentrations of paracetamol in saliva are similar to those in plasma. Concentrations in whole blood are up to 20% higher and in breast milk about 20% lower than the plasma concentration. Paracetamol crosses the placenta.Paracetamol is extensively metabolized in the liver and the total body clearance is about 5 mL/kg/min. The clearance of paracetamol is reduced and the half-life increased following a hepatotoxic overdose. Prolongation beyond 4 hours usually indicates impending liver damage.Two to five percent of a therapeutic dose of paracetamol is excreted unchanged in the urine. Its renal clearance is about 10 mL/min and is weakly dependent on urine flow rate but on pH.Injection: The pharmacokinetics of paracetamol after a single 1000 mg intravenous dose (as a 20 mg/mL solution over 5 minutes) was measured in six healthy male subjects. Data was interpreted as a two-compartment open model. The decline in plasma paracetamol concentration (Ct) after intravenous administration appeared to be bi-exponential. An initial rapid fall over the first 1.5 hours was followed by a mono-exponential decline over the remaining 4.5 hours of observation. The half-life (T1/2α) of the first exponential ranged from 0.15 to 0.53 hour (mean = 0.32 hour) and that of the second exponential (T½β) ranged from 2.24 to 3.30 hours (mean = 2.50 hours). Plasma clearance (Vp) ranged from 264 to 505 mL/min (mean = 352±40 mL/min). The area under the plasma concentration time curve (AUC) was measured to be 50.5±5.7 µg/mL.h.Paracetamol is not bound to plasma proteins by any extent. The concentrations of paracetamol in saliva are similar to those in plasma. Concentrations in whole blood are up to 20% higher and in breast milk about 20% lower than the plasma concentration. Paracetamol crosses the placenta.Paracetamol is extensively metabolized in the liver. About 80 to 85% of paracetamol in the body undergoes conjugation principally with glucuronic acid and to lesser extent with sulfuric acid. Small quantities of paracetamol are metabolized by a cytochrome P-450 microsomal enzyme to a reactive intermediate metabolite (N-acetyl-p-benzoquinoneimine) which is further metabolized via conjugation with glutathione and ultimately excreted in urine as mercapturic acid and cysteine conjugates of paracetamol. This intermediate metabolite is suggested to be responsible for paracetamol-induced liver necrosis; high doses of paracetamol may deplete glutathione so that inactivation of this toxic metabolite is decreased. At high paracetamol doses, the capacity for conjugation with glucuronic acid and sulfuric acid may be exceeded, resulting in increased metabolism of paracetamol by alternative pathways. Following a hepatotoxic overdose, the clearance of paracetamol is reduced and the half-life increased. Prolongation beyond four hours usually indicates impending liver damage.Two to five percent of a therapeutic dose of paracetamol is excreted unchanged in the urine. Its renal clearance is about 10 mL/min and is weakly dependent on urine flow rate but not on pH.