This information is intended for use by health professionals

1. Name of the medicinal product


Nytol Original 25mg Tablets

Numark Sleep Aid 25mg Tablets

Superdrug Sleep Aid 25mg Tablets

Sleepeaze 25mg Tablets

Asda Night Time Sleep Aid 25mg Tablets

Morrisons Sleep Aid 25mg Tablets

Tesco Sleep Aid 25mg Tablets

2. Qualitative and quantitative composition

Nytol contains 25mg Diphenhydramine Hydrochloride per tablet.

3. Pharmaceutical form

Tablets to be taken orally.

4. Clinical particulars
4.1 Therapeutic indications

An aid to the relief of temporary sleep disturbance.

4.2 Posology and method of administration

Oral administration only.

Two tablets to be taken 20 minutes before going to bed, or as directed by a physician.

Do not exceed the stated dose or frequency of dosing.

Do not use in children under 16 years.

This medication should not be used continuously for more than 2 weeks without consulting a doctor.

4.3 Contraindications

Hypersensitivity to the active substance or to any of the excipients listed in section 6.1 Nytol is contraindicated in those with the following conditions: stenosing peptic ulcer, pyloroduodenal obstruction.

4.4 Special warnings and precautions for use

Nytol should be used with caution in patients with myasthenia gravis, epilepsy or seizure disorders, narrow-angle glaucoma, prostatic hypertrophy, urinary retention, asthma, bronchitis and chronic obstructive pulmonary disease (COPD), moderate to severe hepatic impairment and moderate to severe renal impairment.

Tolerance may develop with continuous use. Seek medical advice if sleeplessness persists, as insomnia may be a symptom of serious underlying medical illness.

This medication should not be used continuously for more than 2 weeks without consulting a doctor.

May increase the effects of alcohol, therefore alcohol should be avoided.

Avoid use of other antihistamine-containing preparations, including topical antihistamines and cough and cold medicines.

Use with caution in the elderly, who are more likely to experience adverse effects. Avoid use in elderly patients with confusion.

Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.

Keep out of the sight and reach of children.

4.5 Interaction with other medicinal products and other forms of interaction

Diphenhydramine may potentiate the sedative effects of alcohol and other CNS depressants (e.g. tranquillizers, hypnotics and anxiolytics).

Monoamine oxidase inhibitors(MAOI) prolong and intensify the anticholinergic effects of diphenhydramine. The product should be used with caution with MAOIs or within 2 weeks of stopping an MAOI.

As diphenhydramine has some antimuscarinic activity, the effects of some anticholinergic drugs (e.g. atropine, tricyclic antidepressants) may be potentiated therefore medical advice should be sought before taking diphenhydramine with such medicines.

Diphenhydramine is an inhibitor of the cytochrome p450 isoenzyme CYP2D6. Therefore, there may be a potential for interaction with drugs which are primarily metabolised by CYP2D6, such as metoprolol and venlafaxine.

Diphenhydramine should not be used in patients receiving any of the above drugs unless directed by a doctor.

4.6 Fertility, pregnancy and lactation


Diphenhydramine crosses the placenta. Because animal reproduction studies are not always predictive of human response and since there is inadequate experience with use of diphenhydramine in pregnant women, the potential risk for humans is unknown. Use of sedating antihistamines during the third trimester may result in reactions in the newborn or premature neonates. This drug is not recommended during pregnancy. Consult a doctor before use.


Diphenhydramine has been detected in breast milk, but the effect of this on breastfed infants is unknown. Nytol is not recommended for use during lactation. Consult a doctor before use.

4.7 Effects on ability to drive and use machines

Nytol is a hypnotic and will produce drowsiness or sedation soon after the dose has been taken. It may also cause dizziness, blurred vision, cognitive and psychomotor impairment. These can seriously affect the patient's ability to drive and use machines. If affected, do not drive or operate machinery.

4.8 Undesirable effects

Specific estimation of the frequency of adverse events for OTC products is inherently difficult (particularly numerator data). Adverse reactions which have been observed in clinical trials and which are considered to be common (occurring in > 1/100 to < 1/10) or very common (occurring in > 1/10) are listed below by MedDRA System Organ Class. The frequency of other adverse reactions identified during post- marketing use is unknown, but these reactions are likely to be uncommon (occurring in > 1/1,000 to <1/100) or rare (occurring in < 1/1,000).

Body System

Undesirable effect


General disorders and administration site conditions



Immune system disorders

Hypersensitivity reactions including rash, urticaria, dyspnoea and angioedema


Psychiatric disorders*

confusion, paradoxical excitation (e.g. increased energy, restlessness, nervousness)


Nervous system disorders

sedation, drowsiness, disturbance in attention, unsteadiness, dizziness, convulsions, headache, paraesthesia, dyskinesias, hypoesthesia, restless leg syndrome



Eye disorders

blurred vision


Cardiac disorders

tachycardia, palpitations


Respiratory, thoracic and mediastinal disorders

thickening of bronchial secretions


Gastrointestinal disorders

dry mouth

gastrointestinal disturbance including nausea, vomiting



Musculoskeletal and connective tissue disorders

muscle twitching


Renal and urinary disorders

urinary difficulty, urinary retention


* The elderly are more prone to confusion and paradoxical excitation.

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, website: or search for MHRA Yellow Card in the Google Play or Apple app Store.

4.9 Overdose

Overdose is likely to result in effects similar to those listed under adverse reactions. Additional symptoms may include mydriasis, fever, flushing, agitation, tremor, dystonic reactions, hallucinations and ECG changes. Large overdose may cause rhabdomyolysis, convulsions, delirium, toxic psychosis, arrhythmias, coma and cardiovascular collapse.

Treatment should be supportive and directed towards specific symptoms. Convulsions and marked CNS stimulation should be treated with parenteral diazepam.

5. Pharmacological properties
5.1 Pharmacodynamic properties

Diphenhydramine is an ethanolamine-derivative antihistamine. It is an antihistamine with anticholinergic and marked sedative effects. It acts by inhibiting the effects on H1-receptors.

Diphenhydramine is effective in reducing sleep onset (ie, time to fall asleep) and increasing the depth and quality of sleep.

5.2 Pharmacokinetic properties


Diphenhydramine hydrochloride is rapidly absorbed following oral administration. Apparently it undergoes first-pass metabolism in the liver and only about 40-60% of an oral dose reaches systematic circulation as unchanged Diphenhydramine.


It is rapidly distributed throughout the whole body. Peak plasma concentrations are attained within 1-4 hours. The sedative effect also appears to be maximal within 1-3 hours after administration of a single dose.

It is positively correlated with the plasma drug concentration.


Diphenhydramine is approx 80-85% bound to plasma proteins. Diphenhydramine is rapidly and almost completely metabolised. The drug is metabolised principally to Diphenylmetoxyacetic acid and is also dealkylated.

The metabolites are conjugated with glycine and glutamine and excreted in urine. Only about 1% of a single dose is excreted unchanged in urine.


The elimination half-life ranges from 2.4-9.3 hours in healthy adults. The terminal elimination half-life is prolonged in liver cirrhosis.

5.3 Preclinical safety data

None stated.

6. Pharmaceutical particulars
6.1 List of excipients

Anhydrous lactose

Stearic acid, powder

Microcrystalline cellulose

Silicon dioxide

Maize starch

6.2 Incompatibilities

Not applicable.

6.3 Shelf life

Nytol has a shelf-life of 4 years in HDPE bottles and 3 years in blister packs.

6.4 Special precautions for storage

Store in a dry place.

6.5 Nature and contents of container

High density polyethylene bottles with a polypropylene closure and cotton wool wadding, or an aclar/polyethylene/PVC or PVC/PVDC strip with a heat sealable aluminium foil. Bottles of 16 or 20 tablets and strips of 4, 8, 16, 20 or 24 tablets.

6.6 Special precautions for disposal and other handling

Not applicable.

7. Marketing authorisation holder

Omega Pharma Ltd.

1st Floor

32 Vauxhall Bridge Road



United Kingdom

8. Marketing authorisation number(s)

PL 02855/0071

9. Date of first authorisation/renewal of the authorisation

21 September 1992 / 29 October 2002

10. Date of revision of the text

March 2021