Appetite suppressants and amphetamine-like psycho-stimulants: risk of hypertension.

Oxytocin: risk of hypertension.

Enhances effects of anticholinergic drugs (such as TCAs).

Should not be given with other sympathomimetics such as decongestants, and thyroid hormones. Should not be given to patients undergoing general anaesthesia as them may induce ventricular arrhythmias.

Guaifenesin

If urine is collected within 24 hours of a dose of guaifenesin a metabolite of guaifenesin may cause a colour interference with laboratory determinations of urinary 5-hydroxyindoleacetic acid (5-HIAA) and vanillylmandelic acid (VMA).

4.6 Pregnancy and lactation
Since the product is intended only for use in children, information on its use in pregnancy and lactation is not relevant.

4.7 Effects on ability to drive and use machines
No adverse effects known.

4.8 Undesirable effects
Guaifenesin

The following side effects may be associated with the use of guaifenesin:

Gastrointestinal disorders: nausea, vomiting, gastrointestinal discomfort.

Immune system disorders: hypersensitivity reactions.

Pseudoephedrine

Cardiovascular disorders: tachycardia, palpitations, other cardiac dysrythmias.

Gastrointestinal disorders: nausea and/or vomiting, dry mouth.

General disorders and administration site conditions: irritability, thirst, tolerance with dependence has been reported with prolonged administration of pseudoephedrine-containing preparations.

Immune system disorders: hypersensitivity reactions, including cross-sensitivity that may occur with other sympathomimetics.

Musculoskeletal and connective tissue disorders: muscular weakness.

Nervous system disorders: headache, giddiness, tremor, anxiety, restlessness, excitability, insomnia, hallucinations (particularly in children) and paranoid delusions.

Psychiatric disorders: sleep disturbance.

Renal and urinary disorders: difficulty in micturition including urinary retention.

Skin and subcutaneous tissue disorders: skin reactions including rash, sweating.

Vascular disorders: hypertension.

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: www.mhra.gov.uk/yellowcard.
4.9 Overdose
Symptoms of overdosage include headache, nausea, vomiting, tachycardia, urinary retention, hallucinations, coma, tremor, excitement, convulsions, respiratory depression, hypertension and arrhythmias.

Initial treatment consists of either emesis or gastric lavage, if appropriate. Otherwise treatment should be symptomatic and supportive, including the administration of a beta blocker if supraventricular tachycardia supervenes.

5. Pharmacological properties
5.1 Pharmacodynamic properties
Pseudoephedrine acts directly on both alpha and to a lesser extent beta adrenergic receptors. It is believed that the alpha adrenergic effects result from inhibition of the production of cyclic AMP by inhibition of the enzyme adenyl cyclase, whereas beta adrenergic eff