Paracetamol, Orphenadrine citrate.
Norpriexia: Each film-coated tablet contains: Paracetamol, BP 450 mg, Orphenadrine Citrate, BP 35 mg.
Norpriexia Forte: Each film-coated tablet contains: Paracetamol, BP 650 mg, Orphenadrine Citrate, BP 35 mg.
Pharmacology: Paracetamol, a para-aminophenol derivative, is a peripherally acting analgesic with antipyretic and weak anti-inflammatory activity. Orphenadrine, is a skeletal muscle relaxant and is postulated to act on cerebral motor center or on the medulla through an atropine-like central action. It has anticholinergic, local anaesthetic effects and some antihistaminic effects.
Pharmacodynamics: Mechanism of Action: Orphenadrine is a skeletal muscle relaxant. Paracetamol is an analgesic and antipyretic.
Pharmacokinetics: Paracetamol: is a readily absorbed from the gastrointestinal tract with peak plasma concentration occurring about 10 to 60 minutes after oral doses. Paracetamol is distributed into most body tissues. It crosses the placenta and is present in breast milk. Plasma-protein binding is negligible at usual therapeutic concentration but increases with the increasing concentrations. The elimination half-life of Paracetamol varies from about 1 to 3 hours. Paracetamol is metabolised mainly in the liver and excreted in the urine mainly as the glucuronide and sulfate conjugates. Less than 5% is excreted as unchanged Paracetamol. A minor hydroxylated metabolite (N-acetyl-p-benzoquinoneimine), is usually produced very small amounts by cytochrome P450 isoenzymes (mainly CYP2E1 and CYP3A4) in the liver and kidney. It is usually detoxified by conjugation with glutathione but may accumulate after Paracetamol overdosage and cause tissue damage.
Orphenadrine: is readily absorbed from the gastrointestinal tract, it is almost completely metabolised to at least 8 metabolites. It is mainly excreted in the urine as metabolites and small amount of unchanged drug. The half-life of orphenadrine has been reported to be 14 hours.
Paracetamol: has analgesic and antipyretic properties and used for the short-term treatment of moderate pain, particularly after surgery, and for fever.
Orphenadrine: is also used as to relieve pain due to skeletal muscle spasm sand with the paracetamol used in the treatment of musculoskeletal and joint disorder.
Usual Oral Dose: Two Tablets, three or four times daily.
Or as prescribed by the physician.
Symptoms and Signs: Orphenadrine overdosage: Known symptoms with orphenadrine include tachycardia, excitement, confusion and delirium leading to coma. Convulsions, dilated pupils and urinary retention may occur.
Paracetamol overdosage: Toxic symptoms following an overdose with paracetamol include vomiting, abdominal pain, hypotension, sweating, central simulation with exhilaration and convulsions in children, drowsiness, respiratory depression, cyanosis and coma. In adults, hepatotoxicity may occur after ingestion of a single dose of paracetamol 10 to 15 g; a dose of 25 g or more is potentially fatal.
Symptoms during the first two days of acute poisoning by paracetamol do not reflect the potential seriousness of the intoxication. Major manifestations of liver failure such as jaundice, hypoglycemia and metabolic acidosis may take at least three days to develop.
Treatment: Prompt treatment is essential when there are no obvious symptoms.
In cases of overdosage, methods of reducing absorption of ingested medicine are important.
Prompt administration of activated charcoal 50 g in 150 mL of water and 150 mL sorbitol 50% solution by mouth may reduce absorption. It is recommended that intravenous fluids such as normal saline be given concurrently. Gastric lavage is indicated if the patient is unwillingly or unable to drink an activated charcoal/sorbitol mixture.
If the history suggests that paracetamol 150 mg/kg body weight or 15 g total or more has been ingested, administer the following antidote: Intravenous acetylcysteine 20%: Administer acetylcysteine immediately without waiting for positive urine test or plasma level results if 8 hours or less since overdose ingestion. Initial dose 150 mg/kg over 15 minutes, followed by continuous infusion of 50 mg/kg in glucose 5% 500 mL over four hours and 100 mg/kg in glucose 5% 1 l over 16 hours. If more than eight hours have been elapsed since the overdose was taken, the antidote may be less effective. Convulsions and delirium respond to relatively large doses of diazepam, preferably by mouth.
Adequate hydration of the patient is important.
Hypersensitivity to the active substance or to any of the excipients.
Paracetamol should be given with care to patients with impaired kidney or liver function. It should also be given with care to patients with alcohol dependence. Caution is advised for patients with impaired kidney or liver function, or in patients with cardiac failure, coronary insufficiency, cardiac arrhythmias and tachycardia.
Pregnancy: Paracetamol + Orphenadrine is not recommended for use during pregnancy.
Lactation: It is unknown whether Orphenadrine is excreted during lactation. However it is established that Paracetamol is excreted into the breast milk. one to two hours after oral administration.
Adverse effects of Paracetamol are rare and usually mild, although haematological reactions including thrombocytopenia, leucopenia, pancytopenia, neutropenia, and agranulocytosis have been reported. Skin rashes and other hypersensitivity reactions occur occasionally.
Orphenadrine adverse effects include dryness of mouth with difficulty in swallowing and talking, thirst, reduced bronchial secretions, dilations of the pupils with loss of accommodation and photophobia, flushing and dryness of skin, transient bradycardia followed by tachycardia with palpitation and arrhythmias and difficulty in micturition as well as reduction in the tone and motility of the gastrointestinal tract leading to constipation.
The risk of Paracetamol toxicity may be increased in patients receiving other potentially hepatotoxic drugs or drugs that induce liver microsomal enzymes. The absorption of Paracetamol may be accelerated by drugs such as metoclopramide. Excretion may be affected and plasma concentrations altered when given with Probenecid.
Colestyramine reduces the absorption of Paracetamol if given within 1 hour of Paracetamol.
Orphenadrine is an inhibitor of the cytochrome P450 isoenzymes CYP2B6 which is involved in the metabolism of bupropion to its major metabolites, should be used with caution in patients also receiving bupropion.
Store at temperatures not exceeding 30°C.
M03BC51 - orphenadrine, combinations ; Belongs to the class of ethers. Used as centrally-acting muscle relaxants.
Norpriexia Forte FC tab
100's
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