Summary of medicine characteristics - TRIHEXYPHENIDYL TABLETS 2 MG, ARTANE TABLETS 2 MG
Trihexyphenidyl Tablets 2mg
Artane Tablets 2mg
2 QUALITATIVE AND QUANTITATIVE COMPOSITION
2 QUALITATIVE AND QUANTITATIVE COMPOSITIONTrihexyphenidyl 2mg contains 2mg trihexyphenidyl hydrochloride BP.
For a full list of excipients, see section 6.1.
3. PHARMACEUTICAL FORM
4.1. Therapeutic Indications
4.3 Contraindications
Hypersensitivity to trihexyphenidyl or any of the other ingredients.
4.4 Special warnings and precautions for use
Precautions: Since the use of trihexyphenidyl may, in some cases, continue indefinitely, the patient should be under careful observation over the long term. It should be administered with care to avoid allergic or other untoward reactions.
Except in the case of vital complications, abrupt discontinuation of the drug should be avoided.
Incipient glaucoma may be precipitated by para-sympatholytic drugs such as trihexyphenidyl.
Hypertension, cardiac, liver or kidney disorders are not contra-indicated, but such patients should be followed closely. As trihexyphenidyl may provoke or exacerbate tardive dyskinesia, it is not recommended for use in patients with this condition.
Trihexyphenidyl should be used with caution in patients with glaucoma, obstructive disease of the gastro-intestinal or genito-urinary tracts, and in elderly males with possible prostatic hypertrophy.
Since trihexyphenidyl has been associated with the clinical worsening of myasthenia gravis, the drug should be avoided or used with great caution in patients with this condition.
Since certain psychiatric manifestations such as confusion, delusions and hallucinations, all of which may occur with any of the atropine-like drugs, have been reported rarely with trihexyphenidyl, it should be used with extreme caution in elderly patients (see Dosage and Administration).
Warnings: Trihexyphenidyl may be the subject of abuse (on the basis of hallucinogenic or euphoriant properties, common to all anti-cholinergic drugs) if given in sufficient amounts.
4.5 Interaction with other medicinal products and other forms of interaction
Extra care should be taken when trihexyphenidyl is given concomitantly with phenothiazines, clozapine, antihistamines, disopyramide, nefopam and amantadine because of the possibility of increased antimuscarinic side-effects.
Synergy has been reported between trihexyphenidyl and tricyclic antidepressants, probably because of an additive effect at the receptor site. This can cause dry mouth, constipation and blurred vision. In the elderly, there is a danger of precipitating urinary retention, acute glaucoma or paralytic ileus.
Monoamine oxidase inhibitors can interact with concurrently administered anticholinergic agents including trihexyphenidyl. This can cause dry mouth, blurred vision, urinary hesitancy, urinary retention and constipation.
In general, anticholinergic agents should be used with caution in patients who are receiving tricyclic antidepressants or monoamine oxidase inhibitors. In patients who are already on antidepressant therapy the dose of trihexyphenidyl should be initially reduced and the patient reviewed regularly.
Trihexyphenidyl may be antagonistic with the actions of metoclopramide and domperidone on gastro-intestinal function.
The absorption of levodopa may possibly be reduced when used in conjunction with trihexyphenidyl.
Trihexyphenidyl may be antagonistic with the actions of parasympathomimetics.
4.6 Pregnancy and lactation
Pregnancy: There is inadequate information regarding the use of trihexyphenidyl in pregnancy. Animal studies are insufficient with regard to effects on pregnancy, embryonal/foetal development, parturition and postnatal development. The potential risk for humans is unknown. Trihexyphenidyl should not be used during pregnancy unless clearly necessary.
Lactation: It is unknown whether trihexyphenidyl is excreted in human breast milk. The excretion of trihexyphenidyl in milk has not been studies in animals. Infants may be very sensitive to the effects of antimuscarinic medications. Trihexyphenidyl should not be used during breast-feeding.
4.7. Effects on Ability to Drive and Use Machines
Can cause blurring of vision, dizziness and mild nausea. Also mental confusion in some cases.
4.8 Undesirable effects
Modern clinical data required to determine the frequency of undesirable effects are lacking for trihexyphenidyl. Minor side effects such as dryness of mouth, constipation, blurring of vision, dizziness, mild nausea or nervousness will be experienced by 30–50% of all patients. These reactions tend to become less pronounced as treatment continues. Patients should be allowed to develop a tolerance using the smaller initial dose until an effective level is reached.
Immune system disorders: Hypersensitivity.
Psychiatric disorders: Nervousness, restlessness, confusional states, agitation, delusions, hallucinations, insomnia, especially in the elderly and patients with arteriosclerosis. The development of psychiatric disturbances may necessitate discontinuation of treatment.
Euphoria may occur. There have been reports of abuse of trihexyphenidyl due to its euphoric and hallucinogenic properties.
Nervous system disorders: Dizziness.
Impairment of immediate and short-term memory function has been reported. Worsening of myasthenia gravis may occur (see section 4.4).
Eye disorders: Dilatation of the pupils with loss of accommodation and photophobia, raised intraocular pressure (see section 4.4).
Cardiac disorders: Tachycardia.
Respiratory, thoracic and mediastinal disorders: Decreased bronchial secretions.
Gastrointestinal disorders: Dry mouth with difficulty swallowing, constipation, nausea, vomiting.
Skin and subcutaneous tissue disorders: Flushing and dryness of skin, skin rashes.
Renal and urinary disorders: Urinary retention, difficulty in micturition.
General disorders: Thirst, pyrexia.
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 or search for ‘MHRA Yellow Card’ in the Google Play or Apple App Store.
4.9 Overdose
4.9 OverdoseSymptoms: Symptoms of overdose with antimuscarinic agents include flushing and dryness of the skin, dilated pupils, dry mouth and tongue, tachycardia, rapid respiration, hyperpyrexia, hypertension, nausea, vomiting. A rash may appear on the face or upper trunk. Symptoms of CNS stimulation include restlessness, confusion, hallucinations, paranoid and psychotic reactions, incoordination, delirium and occasionally convulsions. In severe overdose, CNS depression may occur with coma, circulatory and respiratory failure and death.
Treatment: Treatment should always be supportive. An adequate airway should be maintained. Diazepam may be administered to control excitement and convulsions but the risk of central nervous system depression should be considered. Hypoxia and acidosis should be corrected. Antiarrhythmic drugs are not recommended if dysrhythmias occur.
5.1 Pharmacodynamic properties
Trihexyphenidyl hydrochloride is an anticholinergic agent. It is an antispasmodic drug which exerts a direct inhibitory effect on the parasympathetic nervous system. It diminishes salivation, increases the heart rate, dilates the pupils and reduces spasm of smooth muscle.
5.2. Pharmacokinetic Properties
Trihexyphenidyl hydrochloride is well absorbed from the gastrointestinal tract. It disappears rapidly from the plasma and tissues and does not accumulate in the body during continued administration of conventional doses.
5.3. Preclinical Safety Data
5.3. Preclinical Safety DataNone stated.
6.1
Calcium hydrogen phosphate
Magnesium stearate
Starch pregelatinized
Starch
6.2. Incompatibilities
None.
6.3. Shelf Life
60 months.
6.4. Special Precautions for Storage
Store below 25°C. Store in the original package in order to protect from moisture.
6.5. Nature and Contents of Container
HDPE bottle with a child-resistant closure. Pack sizes of 28, 30, 56, 60, 84, 100 and 1000 tablets.
Not all pack sizes may be marketed.