Comtrex multi-symptom (acetaminophen,guaifenesin)

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Comtrex multi-symptom (acetaminophen,guaifenesin) Medicine

Overdose

Paracetamol

Liver damage is possible in adults who have taken 10 g or more of paracetamol. Ingestion of 5 g of more of paracetamol may lead to liver damage if the patient has risk factors (see below).

Risk factors

If the patient:

(a) Is on long-term treatment with carbamazepine, phenobarbitone, phenytoin, primidone, rifampicin, St John's Wort or other drugs that induce liver enzymes.

Or

(b) Regularly consumes ethanol in excess of recommended amounts.

Or

(c) Is likely to be glutathione depleted, e.g. eating disorders, cystic fibrosis, HIV infection, starvation, cachexia.

Symptoms

Symptoms of paracetamol overdose in the first 24 hours are pallor, nausea, vomiting, anorexia and abdominal pain. Liver damage may become apparent 12 to 48 hours after ingestion. Abnormalities of glucose metabolism and metabolic acidosis may occur. In severe poisoning, hepatic failure may progress to encephalopathy, haemorrhage, hypoglycaemia, cerebral oedema and death. Acute renal failure with acute tubular necrosis, strongly suggested by loin pain, haematuria and proteinuria, may develop even in the absence of severe liver damage. Cardiac arrhythmias and pancreatitis have been reported.

Management

Immediate treatment is essential in the management of paracetamol overdose. Despite a lack of significant early symptoms, patients should be referred to hospital urgently for immediate medical attention. Symptoms may be limited to nausea or vomiting and may not reflect the severity of overdose or the risk of organ damage. Management should be in accordance with established treatment guidelines. See BNF overdose section.

Treatment with activated charcoal should be considered if the overdose has been taken within 1 hour. Plasma paracetamol concentration should be measured at 4 hours or later after ingestion (earlier concentrations are unreliable). Treatment with N-acetylcysteine may be used up to 24 hours after ingestion of paracetamol, however, the maximum protective effect is obtained up to 8 hours post-ingestion. The effectiveness of the antidote declines sharply after this time. If required the patient should be given intravenous N-acetylcysteine, in line with the established dosage schedule. If vomiting is not a problem, oral methionine may be a suitable alternative for remote areas, outside hospital. Management of patients who present with serious hepatic dysfunction beyond 24 hours from ingestion should be discussed with the NPIS or a liver unit.

Phenylephrine hydrochloride

Features of severe overdose of phenylephrine include haemodynamic changes and cardiovascular collapse with respiratory depression. Treatment includes early gastric lavage and symptomatic and supportive measures. Hypertensive effects may be treated with an i.v. alpha-receptor blocking agent.

Phenylephrine overdose is likely to result in: nervousness, headache, dizziness, insomnia, increased blood pressure, nausea, vomiting, mydriasis, acute angle closure glaucoma (most likely to occur in those with closed angle glaucoma), tachycardia, palpitations, allergic reactions (e.g. rash, urticaria, allergic dermatitis), dysuria, urinary retention (most likely to occur in those with bladder outlet obstruction, such as prostatic hypertrophy).

Additional symptoms may include, hypertension, and possibly reflex bradycardia. In severe cases confusion, hallucinations, seizures and arrhythmias may occur. However the amount required to produce serious phenylephrine toxicity would be greater than that required to cause paracetamol-related liver toxicity.

Treatment should be as clinically appropriate. Severe hypertension may need to be treated with alpha blocking medicinal products such as phentolamine.

Contraindications

-

- Severe coronary heart disease and cardiovascular disorders.

- Hypertension.

- Hyperthyroidism.

- Contraindicated in patients currently receiving or within two weeks of stopping therapy with monoamine oxidase inhibitors.

Incompatibilities

None known.

Undesirable effects

Paracetamol

Adverse effects of paracetamol are rare, but hypersensitivity including skin rash may occur. There have been a few reports of blood dyscrasias including thrombocytopenia, leucopenia, pancytopenia, neutropenia and agranulocytosis, but these were not necessarily causally related to paracetamol.

Acute pancreatitis after ingestion of above normal amounts.

Phenylephrine hydrochloride

High blood pressure with headache and vomiting, probably only in overdose. Rarely palpitations. Also, rare reports of allergic reactions and occasionally urinary retention in males.

Reporting of Suspected Adverse Reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: http:www.mhra.gov.uk/yellowcard

Preclinical safety data

No preclinical findings of relevance have been reported.

Therapeutic indications

For the relief of the symptoms of colds and influenza, including the relief of aches and pains and nasal congestion, sore throat and lowering of temperature.

Pharmacodynamic properties

ATC Code

N02BE51 - paracetamol, combinations excluding psycholeptics.

Paracetamol

Paracetamol has both analgesic and antipyretic activity which is believed to be mediated principally through its inhibition of prostaglandin synthesis within the central nervous system.

Phenylephrine

Phenylephrine is a postsynaptic alpha-receptor agonist with low cardioselective beta-receptor affinity and minimal central stimulant activity. It is a recognised decongestant and acts by vasoconstriction to reduce oedema and nasal swelling.

Pharmacokinetic properties

Paracetamol

After oral dosing paracetamol is absorbed rapidly and completely mainly from the small intestine producing peak plasma levels after 15-20 minutes. The systemic availability is subject to first-pass metabolism and varies with dose between 70% and 90%. The drug is rapidly and widely distributed throughout the body and is eliminated from plasma with a T½ of approximately 2 hours. The major metabolites are glucuronide and sulphate conjugates (>80%) which are excreted in urine.

Phenylephrine

Phenylephrine is absorbed from the gastrointestinal tract, but has reduced bioavailability by the oral route due to first pass metabolism. It retains activity as a nasal decongestant when given orally, the drug distributing through the systemic circulation to the vascular bed of the nasal mucosa. When taken by mouth as a nasal decongestant phenylephrine is usually given at intervals of 4 to 6 hours.

Name of the medicinal product

Comtrex Multi-Symptom (Acetaminophen,Guaifenesin)

Qualitative and quantitative composition

Guaifenesin; Acetaminophen

Special warnings and precautions for use

Use with caution in patients with Raynaud's Phenomenon or diabetes. Each sachet contains approximately 2.6 g of carbohydrate. Due to its aspartame content this product should not be given to patients with phenylketonuria. Care is advised in the administration of paracetamol to patients with severe renal or severe hepatic impairment. The hazard of overdose is greater in those with non-cirrhotic alcoholic liver disease. Patients should be advised not to take other paracetamol-containing products concurrently.

Label warnings: Do not exceed the stated dose. Keep out of the reach of children. Contains paracetamol (panel). If symptoms persist consult your doctor. If you are pregnant or are being prescribed medicine by your doctor, seek his advice before taking this product. Total sugars 2.6 g. Contains aspartame. Do not take with any other paracetamol-containing products. Immediate medical advice should be sought in the event of an overdose, even if you feel well.

Leaflet: Immediate medical advice should be sought in the event of an overdose, even if you feel well, because of the risk of delayed, serious liver damage. Contains a source of phenylalanine. May be harmful for people with phenylketonuria. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicinal product.

Effects on ability to drive and use machines

Lemsip Cold & Flu Breathe Easy has no or negligible influence on ability to drive or use machinery.

Dosage (Posology) and method of administration

Patients should consult a doctor or a pharmacist if symptoms persist for more than 3 days, or worsen.

Posology

Adults, the elderly and children aged 16 and over: Content of one sachet dissolved by stirring in hot water and sweetened to taste.

Dose may be repeated every 4-6 hours as required.

Do not take more than 4 sachets in 24 hours.

Do not give to children under 16 years of age.

Elderly Population: No dosage adjustment is considered necessary in the elderly.

Method of Administration

Oral administration after dissolution in water.

Special precautions for disposal and other handling

Oral administration, after dissolution in hot water.