This information is intended for use by health professionals

1. Name of the medicinal product

Benylin Dual Action Night Cough & Congestion

Benylin Mucus Cough Night

2. Qualitative and quantitative composition

Each 5 ml contains Diphenhydramine hydrochloride 14 mg, Guaifenesin 100 mg and Levomenthol 1.1 mg.

For a full list of excipients, see section 6.1.

3. Pharmaceutical form

A clear red syrup with no insoluble matter.

4. Clinical particulars
4.1 Therapeutic indications

For the night time relief of cough, associated congestive symptoms and aiding restful sleep.

4.2 Posology and method of administration

For oral use.

Adults and children aged 12 years and over:

Patients may start with two 5 ml spoonfuls at bedtime followed by two 5 ml spoonfuls every 6 hours.

Or two 5 ml spoonfuls four times a day.

Do not take more than 4 doses (1 dose = two 5 ml spoonfuls) in 24 hours.

Children under 12 years:

This medicine is contraindicated in children under the age of 12 years (see section 4.3).

Elderly (over 65 years):

As for adults.

Do not exceed the stated dose.

Keep out of the reach and sight of children.

4.3 Contraindications

Known hypersensitivity to the product or any of its constituents.

This product should not be administered to patients currently receiving monoamine oxidase inhibitors (MAOIs) or those patients who have received treatment with MAOIs within the last two weeks.

Not to be used in children under the age of 12 years.

4.4 Special warnings and precautions for use

This product should be not used for persistent or chronic cough, such as occurs with asthma, or where cough is accompanied by excessive secretions, unless directed by a physician.

Subjects with moderate to severe renal or hepatic dysfunction or urinary retention should exercise caution when using this product (see section 5.2).

This product contains diphenhydramine and should be used with caution in patients with narrow-angle glaucoma or symptomatic prostatic hypertrophy.

Avoid alcoholic drink.

The label contains the following statements:

May cause drowsiness. If affected, do not drive or operate machinery.

Avoid alcoholic drink. Do not use if bottle seal is broken when purchased. Keep bottle tightly closed. Do not store above 30°C. Keep out of the reach and sight of children. As with all medicines, if you are pregnant consult your doctor or pharmacist before taking this product.

4.5 Interaction with other medicinal products and other forms of interaction

This product contains diphenhydramine and therefore may potentiate the effects of alcohol, codeine, antihistamines and other CNS depressants.

As diphenhydramine possesses some anticholinergic activity, the effects of anticholinergics (e.g. some psychotropic drugs and atropine) may be potentiated by this product. This may result in tachycardia, dry mouth, gastrointestinal disturbances (e.g. colic), urinary retention and headache.

4.6. Pregnancy and lactation

As with any other medicine, care should be taken in administration during pregnancy. This product has not been associated with adverse effects in the human foetus or suckling infant.

4.7 Effects on ability to drive and use machines

This preparation may cause drowsiness. If affected, the patient should not drive or operate machinery.

4.8 Undesirable effects

Diphenhydramine may cause drowsiness, dizziness, gastrointestinal disturbance; dry mouth nose and throat; difficulty in urination or blurred vision. Less frequently it may cause palpitations, tremor, convulsions or paraesthesia. Hypersensitivity reactions have been reported, in particular, skin rashes, erythema, urticaria and angiodema.

Gastro-intestinal discomfort, nausea and vomiting have occasionally been reported with guaifenesin particularly in large doses.

Adverse reactions to levomenthol at the low concentration present are not anticipated.

4.9 Overdose

Gastric lavage in the conscious patient and intensive supportive therapy where necessary, as with cases of overdose with antihistaminic drugs.

5. Pharmacological properties
5.1 Pharmacodynamic properties

Diphenhydramine is a potent antihistamine and antitussive with anticholinergic and sedative properties. Recent experiments have shown that the antitussive action is discrete from H1-receptor blockade and is located in the brain stem.

Guaifenesin is reported to reduce the viscosity of tenacious sputum and is used as an expectorant.

Levomenthol has mild local anaesthetic and decongestant properties.

5.2 Pharmacokinetic properties

Diphenhydramine is well absorbed in the gastro-intestinal tract. Peak serum levels are reached at between 2 - 2.5 hours after an oral dose. Duration of activity is between 4 - 8 hours. The drug is widely distributed throughout the body, including the CNS, and some 78% is bound to plasma proteins. Estimates of the volume of distribution lie in the range 3.3 - 6.8 l/kg.

Diphenhydramine experiences extensive first-pass metabolism, undergoing two successive N-Demethylations; the resultant amine is then oxidised to a carboxylic acid. Values for plasma clearance lie in the range 600 - 1300 ml/min and the terminal elimination half life lies in the range 3.4 - 9.3 hours. Little unchanged drug is excreted in the urine.

Pharmacokinetic studies in elderly subjects indicate no major differences in drug distribution or elimination compared with younger adults.

Guaifenesin is readily absorbed after oral administration. It is rapidly metabolised by oxidation to β-(2-methyoxy-phenoxy) lactic acid. About 40% of a dose is excreted as this metabolite in the urine in 3 hours.

After absorption Levomenthol is conjugated in the liver and excreted both in the urine and bile as the glucuronide.

Renal Dysfunction

The results of a review on the use of diphenhydramine in renal failure suggest that in moderate to severe renal failure, the dose interval should be extended by a period dependant on glomerular filtration rate (GFR)

Hepatic Dysfunction

After intravenous administration of 0.8 mg/kg Diphenhydramine, a prolonged half-life was noted in patients with chronic liver disease which correlated with the severity of the disease. However, the mean plasma clearance and apparent volume of distribution were not significantly affected.

5.3 Preclinical safety data

There are no pre-clinical data of relevance to the prescriber which are additional to those already included in other sections of the SPC.

6. Pharmaceutical particulars
6.1 List of excipients

Sodium benzoate (E211)


Glucose liquid


Citric acid monohydrate

Sodium citrate

Saccharin sodium

Ethanol 96%

Caramel (E150d)

Ponceau 4R (E124)

Concentrated raspberry essence

Natural sweetness enhancer


Purified water

6.2 Incompatibilities

None known

6.3 Shelf life

24 months

6.4 Special precautions for storage

Do not store above 30°C. Do not refrigerate or freeze.

6.5 Nature and contents of container

125, 150 or 300 ml amber glass bottles with a 2 piece plastic child resistant, tamper evident closure fitted with a polyterephtalate ethylene faced aluminium/expanded polyethylene laminated wad

6.6 Special precautions for disposal and other handling

None applicable.

Administrative data
7. Marketing authorisation holder

McNeil Products Limited

Foundation Park

Roxborough Way


Berkshire SL6 3UG

United Kingdom

8. Marketing authorisation number(s)

PL 15513/0050

9. Date of first authorisation/renewal of the authorisation

16 June 1997 / 27 July 2001

10. Date of revision of the text

11 January 2012