This information is intended for use by health professionals

1. Name of the medicinal product

Myotonine Tablets 25 mg

2. Qualitative and quantitative composition

Each 25 mg tablet weighs 440 mg; total active ingredient 25 mg bethanechol chloride USPXXIV.

For the full list of excipients, see section 6.1.

3. Pharmaceutical form

Each 25 mg tablet is white, flat with bevelled edge and with a cross score and the embossment “MY25”.

4. Clinical particulars
4.1 Therapeutic indications

Urinary retention -acute postoperative, postpartum and neurogenic.

Reflux oesophagitis.

4.2 Posology and method of administration


Paediatric population

The experience with children is limited; therefore no recommended dose is given.


10 mg - 25 mg 3-4 times daily. Taken ½ hr before food.

Occasionally it may be felt necessary to initiate therapy with a 50 mg dose.


Adult dosage administered with caution.

Method of administration

Administration orally by tablets.

4.3 Contraindications

Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.

Intestinal or urinary obstruction, recent myocardial infarction, recent intestinal anastomosis.

4.4 Special warnings and precautions for use

A severe cholinergic reaction is likely to occur if bethanechol chloride is administered IV or IM. This reaction has also rarely occurred in cases of hypersensitivity or overdose.

4.5 Interaction with other medicinal products and other forms of interaction

Pharmacological interactions may occur with the following when bethanechol is administered. Quinidine and procainamide which may antagonise cholinergic effects, cholinergic drugs which may have an additive effect, particularly cholinesterase inhibitors.

When administered to patients receiving ganglionic blocking compounds, a critical fall in blood pressure may occur preceded by severe abdominal symptoms.

4.6 Fertility, pregnancy and lactation

Should not be used during pregnancy or lactation.

4.7 Effects on ability to drive and use machines

In some cases the ability to drive and operate machinery may be impaired.

4.8 Undesirable effects

Nausea, vomiting, sweating and intestinal colic.

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:

4.9 Overdose

Symptoms: Include nausea, salivation, lachrymation, eructation, involuntary defecation and urination, transient dyspnoea, palpitation, bradycardia and peripheral vasodilation leading to hypertension, transient heart block and a feeling of constriction under the sternum.

Procedure: The stomach should be emptied by aspiration and lavage.

Give atropine sulphate 1-2 mg intravenously, intramuscularly or subcutaneously to control muscarinic effects. This dose may be repeated every 2-4 hours as necessary.

Supportive treatment includes intravenous administration of diazepam 5-10 mg, muscle twitching may be controlled by small doses of tubocararine (together with assisted respiration), oxygen may be required.

5. Pharmacological properties
5.1 Pharmacodynamic properties

Pharmacotherapeutic group: Parasympathomimetics, Choline esters, Bethanechol,

ATC code: N07AB02

Mechanism of action

Bethanechol is a synthetic choline ester of carbamic acid which possesses a significant acetyl choline-like activity. It is active after oral administration. As a consequence of the very slow hydrolysation by acetylcholinesterase, bethanechol has a prolonged action as has been demonstrated on the urinary tract. The onset of action after oral administration of bethanechol chloride occurs within one hour.

Pharmacodynamic effects

The major pharmacological effects of bethanechol result from interaction of the drug with muscarinic receptor sites of smooth muscles, especially those of the urinary bladder and gastrointestinal tract. In addition, minor but important nicotinic effects have been noted.

5.2 Pharmacokinetic properties

In usual therapeutic doses, bethanechol does not cross the blood brain barrier.

Studies addressing pharmacokinetic-pharmacodynamic association are not available.

5.3 Preclinical safety data

None stated.

6. Pharmaceutical particulars
6.1 List of excipients

Calcium sulfate dihydrate BP

Maize starch BP

Purified talc BP

6.2 Incompatibilities

None known.

6.3 Shelf life

3 years

6.4 Special precautions for storage


Keep out of reach of children.

6.5 Nature and contents of container

The container consists of blister strips of PVC/aluminium foil packed in boxes.

Each container holds 100 tablets.

6.6 Special precautions for disposal and other handling

None stated.

7. Marketing authorisation holder

Glenwood GmbH

Jensenstr. 6

81679 München


8. Marketing authorisation number(s)

PL 22824/0006

9. Date of first authorisation/renewal of the authorisation

04 December 1973 / 20 March 2015

10. Date of revision of the text