Dimetapp PE Sinus Pain
Tablets
Phenylephrine Hydrochloride & Paracetamol
PRODUCT INFORMATION
Product description
Dimetapp PE Sinus Pain tablets are white to off-white round tablets with break-line on one side.
Each tablet contains:
Phenylephrine hydrochloride 5mg and Paracetamol 500mg.
The tablet also contains cellulose-microcrystalline, magnesium stearate, starch-pregelatinised
maize, povidone, crospovidone and water-purified.
Refer to presentation for a complete description of the dosage form.
Pharmacology
Dimetapp PE Sinus Pain tablets contain phenylephrine, a synthetic sympathomimetic amine, which
acts directly on alpha adrenergic receptors; and paracetamol, a p-aminophenol derivative that is
thought to produce analgesia through a central inhibition of prostaglandin synthesis.
Pharmacokinetics:
Phenylephrine has low oral bioavailability owing to irregular absorption and first-pass metabolism
in the gastrointestinal tract and liver by the enzyme monoamine oxidase (MAO). Following oral
administration nasal decongestion may occur within 15 or 20 minutes and may persist for 2-4 hours.
The half-life of phenylephrine is 2-3 hours.
Paracetamol is readily absorbed from the gastrointestinal tract with peak plasma concentrations
occurring about 10 to 60 minutes after oral administration. Paracetamol is distributed into most body
tissues. Paracetamol crosses the placenta and is present in breast milk. Plasma-protein binding is
negligible at usual therapeutic concentrations but increases with increasing doses. The elimination
half-life of paracetamol varies from 1 to 3 hours.
Paracetamol is metabolised predominantly in the liver and excreted in the urine mainly as the
inactive glucuronide and sulfate conjugates. Less than 5% is excreted as unchanged paracetamol.
The metabolites of paracetamol include a minor hydroxylated intermediate, which has hepatotoxic
activity. This intermediate metabolite is detoxified by conjugation with glutathione, however, it can
accumulate following paracetamol overdosage (more than 150mg/kg or 10g total paracetamol
ingested) and if left untreated can cause irreversible liver damage.
Paracetamol is metabolised differently by premature infants, newborns, infants and young children
compared to adults, the sulfate conjugate being predominant.
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Pharmacodynamics/Mechanism of action:
Phenylephrine has direct sympathomimetic activity and is an effective decongestant in the upper
respiratory tract. It elicits a response in the effector tissue by directly stimulating alpha adrenergic
adrenoreceptors.
Sympathomimetic agents are used as nasal decongestants to provide symptomatic relief. They act
by causing vasoconstriction resulting in redistribution of local blood flow, which reduces oedema of
the nasal mucosa, thus improving ventilation, drainage and nasal stuffiness.
Paracetamol is a p-aminophenol derivative that exhibits analgesic and antipyretic activity. It does
not possess anti-inflammatory activity. Paracetamol is thought to produce analgesia through a
central inhibition of prostaglandin synthesis.
Indications
Relief from the symptoms of sinus headache, sinus pain, nasal and sinus congestion. Symptomatic
relief from colds and flu including headaches, body aches and pains. Reduces fever.
Contraindications
Dimetapp PE Sinus Pain tablets are contraindicated for use in patients:
• with known hypersensitivity or idiosyncratic reaction to phenylephrine, paracetamol or any of the
other ingredients in the product
• with severe hypertension or coronary artery disease
• taking or have taken in the last two weeks a monoamine oxidase inhibitor (MAOI)
Do not use in children under 12 years.
Precautions
Dimetapp PE Sinus Pain tablets should be used with caution in patients with:
• cardiovascular disease (including ischaemic heart disease, hypertension, bradycardia,
tachycardia, arteriosclerosis and coronary artery disease)
• thyroid disease
• diabetes mellitus
• glaucoma
• prostatic hypertrophy
• impaired hepatic function
• impaired renal function
Patients should not exceed recommended dosage.
Patients should not take this product if symptoms get worse or lasts longer than few days, unless
directed by a doctor
This product should not be taken with another cough and cold medicine unless directed by a doctor.
This product should be kept out of reach of children.
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Use in pregnancy
Category B2: The active ingredient of Phenylephrine in Dimetapp PE Sinus Pain tablets has been
taken by only a limited number of pregnant women or women of childbearing age, without an
increase in the frequency of malformation or other direct or indirect harmful effects on the human
fetus having been observed. Studies in animals are inadequate, or may be lacking, but available
data shows no evidence of an increased occurrence of fetal damage. Safety in pregnancy has not
been established, therefore Dimetapp PE Sinus Pain tablets should not be used in pregnant
women, or those likely to become pregnant, unless the potential benefits to the patient are weighed
against the possible risk to the foetus.
Use in lactation
Paracetamol is excreted in small amounts (<0.2%) in breast milk but it is not known whether
phenylephrine is distributed into breast milk, therefore Dimetapp Sinus Pain tablets are not
recommended for breastfeeding mothers unless the potential benefits to the patient are weighed
against the possible risk to the infant.
Interaction with other medicines
The following interactions with Phenylephrine/Paracetamol have been noted:
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Monoamine oxidase inhibitors (MAOIs) and antidepressant medication eg tricyclic
antidepressants - may cause a serious increase in blood pressure or hypertensive crisis
Other sympathomimetic agents, such as decongestants, appetite suppressants and
amphetamine-like psychostimulants – may cause an increase in blood pressure and additive
effects
Methyldopa and β-blockers – may cause an increase in blood pressure
Anticoagulant drugs (warfarin) – dosage may require reduction if paracetamol and
anticoagulants are taken for a prolonged period of time
The risk of paracetamol toxicity may be increased in patients receiving other potentially
hepatotoxic drugs or drugs that induce liver microsomal enzymes such as alcohol and
anticonvulsant agents
Paracetamol absorption is increased by substances that increase gastric emptying, e.g.
metoclopramide
Paracetamol absorption is decreased by substances that decrease gastric emptying e.g.
propantheline, antidepressants with anticholinergic properties and narcotic analgesics
Paracetamol may increase chloramphenicol concentrations
Paracetamol excretion may be affected and plasma concentration altered when given with
probenecid
Colestyramine reduces the absorption of paracetamol if given within1 hour of paracetamol
Adverse reactions
The following adverse reactions may be associated with the use of Phenylephrine/Paracetamol
containing products:
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Blood system – Haematological reactions
Cardiac disorders – Palpitations, tachycardia
Gastrointestinal disorders – Nausea , vomiting
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Immune system disorders – Hypersensitivity
Nervous system disorders – Dizziness, headache, psychomotor hyperactivity, tremors,
hallucinations
Psychiatric disorders – Excitability, insomnia, irritability, nervousness, restlessness, anxiety
Skin and subcutaneous tissue disorders – Rashes, urticaria. Very rare cases of serious skin
reactions (including severe cutaneous reactions such as Stevens-Johnson Syndrome, Toxic
Epidermal Necrolysis, and Acute Generalized Exanthematous Pustulosis) have been reported
Vascular disorders – Increased blood pressure, hypertension
Children and the elderly are more likely to experience adverse effects than other age groups.
Dosage
Adults and children 12 years and over:
Take 2 tablets swallowed whole with water. Repeat dose if necessary every 4-6 hours.
Do not exceed 8 tablets in 24 hours.
Adults should not take this product for more than a few days at a time except on medical advice.
Children should not use for more than 48 hours, except on medical advice.
Do not use in children under 12 years.
Overdosage
The following signs or symptoms may be associated with an overdose of
Phenylephrine/Paracetamol:
Cardiac disorders
Bradycardia, palpitations, tachycardia
Gastrointestinal disorders
Nausea, vomiting
Nervous system disorders
Convulsions, dizziness, tremors
Psychiatric disorders
Anxiety, irritability, nervousness, restlessness, insomnia
Vascular disorders
Increased blood pressure, hypertension
In case of overdose, immediately contact the Poisons Information Centre (in Australia, call 13 11 26;
in New Zealand call 0800 764 766) for advice, or go to a hospital straight away even if you feel well
because of the risk of delayed, serious liver damage.
Overdosage with paracetamol if left untreated can result in severe, sometimes fatal liver damage
and rarely, acute renal tubular necrosis.
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Presentation
Dimetapp PE Sinus Pain tablets are white to off-white round tablets in blister pack.
Pack sizes:
Australia: 10’s, 20’s, 24’s & 30’s (Registered); 30’s (Marketed)
New Zealand: 30’s (Registered & Marketed)
Storage
Store below 25°C.
Poison Schedule
Dimetapp PE Sinus Pain tablets are:
Pharmacy Medicine (S2): 30’s.
Not scheduled: 10’s, 20’s & 24’s.
Name and Address of Sponsor
Pfizer Australia Pty Limited
38-42 Wharf Road
West Ryde, NSW 2114 Australia
Australia ☎Toll Free 1800 555 057
Web: www.dimetapp.com.au
Pfizer New Zealand Ltd
Level 3, Pfizer House
14 Normanby Road
Mt Eden, Auckland
New Zealand
New Zealand ☎Toll Free 0800 447 400
Web: www.dimetapp.co.nz
Date of TGA Approval:
25 Aug 2010
Date of Last Amendment:
09 Mar 2015
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CDS: PE 5.0 Page - 5