Oxybutynin 2.5mg Tablets
SUMMARY OF PRODUCT CHARACTERISTICS
1 NAME OF THE MEDICINAL PRODUCT
Oxybutynin 2.5mg Tablets
2 QUALITATIVE AND QUANTITATIVE COMPOSITION
1 tablet contains 2.5 mg of oxybutynin hydrochloride.
For the full list of excipients see section 6.1.
3 PHARMACEUTICAL FORM
Tablet
Embossed with ”OBC” on one side and ”2.5” on the other.
4 CLINICAL PARTICULARS
4.1 Therapeutic indications
Urinary incontinence, urgency and frequency in the unstable bladder, whether due to neurogenic bladder disorders (detrusor hyperreflexia) in conditions such as multiple sclerosis and spina bifida, or to idiopathic detrusor instability (motor urge incontinence).
Paediatric population
Oxybutynin hydrochloride is indicated in children over 5 years of age for:
- Urinary incontinence, urgency and frequency in unstable bladder conditions due to idiopathic overactive bladder or neurogenic bladder disorders (detrusor overactivity).
- Nocturnal enuresis associated with detrusor overactivity, in conjunction with non-drug therapy, when other drug treatment has failed.
4.2 Posology and method of administration
Tablets to be taken orally.
Adults:
The usual dose is 5mg two or three times a day. This may be increased to a maximum of 5mg four times a day to obtain a clinical response provided the side effects are tolerated.
Older People (including frail elderly):
The elimination half-life is increased in the elderly. Therefore, a dose of 2.5 mg twice a day, particularly if the patient is frail, is likely to be adequate. This dose may be titrated upwards to 5 mg two times a day to obtain a clinical response provided the side effects are well tolerated.
Paediatric population:
Children (under 5years of age):
Not recommended.
Children (over 5 years of age):
Neurogenic bladder:
The usual dose is 2.5mg twice a day. This dose may be titrated upwards to 5 mg two or three times a day to obtain a clinical response provided the side effects are tolerated.
Nocturnal enuresis:
The usual dose is 2.5mg twice a day. This dose may be titrated upwards to 5mg two or three times a day to obtain a clinical response provided the side effects are tolerated. The last dose should be given before bedtime.
4.3 Contraindications
• Hypersensitivity to oxybutynin or to any of the excipients listed in section 6.1.
• Patients with bladder outflow obstruction where urinary retention may be precipitated.
• Gastro-intestinal obstructive disorders, intestinal atony or paralytic ileus.
• Toxic megacolon.
• Severe ulcerative colitis.
• Myasthenia gravis.
• Narrow-angle glaucoma or shallow anterior chamber.
4.4 Special warnings and precautions for use
Oxybutynin should be used with caution in the frail elderly and in patients with autonomic neuropathy (such as those with Parkinson’s disease), severe gastrointestinal motility disorders, hepatic or renal impairment, as they may be more sensitive to the effects of the product, particularly the CNS and psychiatric adverse reactions.
Anticholinergics should be used with caution in elderly patients due to the risk of cognitive impairment.
Gastrointestinal disorders: Anticholinergic medicinal products may decrease gastrointestinal motility and should be used with caution in patients with gastrointestinal obstructive disorders, intestinal atony and ulcerative colitis.
Oxybutynin may aggravate tachycardia (and thus hyperthyroidism, congestive heart failure, cardiac arrhythmia, coronary heart disease, hypertension), cognitive disorders and symptoms of prostatic hypertrophy.
Anticholinergic CNS effects (e.g. hallucinations, agitation, confusion, somnolence) have been reported; monitoring recommended especially in first few months after initiating therapy or increasing the dose; consider discontinuing therapy or reducing the dose if anticholinergic CNS effects develop.
Since oxybutynin can cause narrow-angle glaucoma, patients should be advised to contact a physician immediately if they are aware of a sudden loss of visual acuity or ocular pain.
Oxybutynin may reduce salivary secretions which could result in dental caries, parodontosis or oral candidiasis.
When oxybutynin is used in high environmental temperatures, this can cause heat prostration due to decreased sweating.
Anticholinergic medicinal products should be used with caution in patients who have hiatus hernia/gastro-oesophageal reflux and/or who are concurrently taking medicinal products (such as bisphosphonates) that can cause or exacerbate oesophagitis.
Paediatric population
There is limited evidence supporting the use of oxybutynin in children with monosymptomatic nocturnal enuresis (not related to detrusor overactivity). The use of oxybutynin in children under 5 years of age is not recommended; it has not been established whether oxybutynin can be safely used in this age group.
In children over 5 years of age, oxybutynin hydrochloride should be used with caution as they may be more sensitive to the effects of the product, particularly the CNS and psychiatric adverse reactions.
Lactose warning: Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.
4.5 Interaction with other medicinal products and other forms of interaction
The anticholinergic activity of oxybutynin is increased by concurrent use of other anticholinergics or medicinal products with anticholinergic activity, such as amantadine and other anticholinergic antiparkinsonian medicinal products (e.g.
biperiden, levodopa), antihistamines, antipsychotics (e.g. phenothiazines, butyrophenones, clozapine), quinidine, digitalis, tricyclic antidepressants, atropine and related compounds like atropinic antispasmodics and dipyridamole.
By reducing gastric motility, oxybutynin may affect the absorption of other drugs.
Oxybutynin is metabolised by cytochrome P 450 isoenzyme CYP 3A4. Concomitant administration with a CYP3A4 inhibtor can inhibit oxybutynin metabolism and increase oxybutynin exposure.
Oxybutynin may antagonize prokinetic therapies.
Concomitant use with cholinesterase inhibitors may result in reduced cholinesterase inhibitor efficacy.
Patients should be informed that alcohol may enhance the drowsiness caused by anticholinergic agents such as oxybutynin (see section 4.7).
4.6 Fertility, pregnancy and lactation
Pregnancy:
There are no adequate data from the use of oxybutynin in pregnant women. Animal studies are insufficient with respect to effects on pregnancy, embryonal/foetal development, parturition or postnatal development (see section 5.3). The potential risk for humans is unknown. Oxybutynin should not be used during pregnancy unless clearly necessary.
Breast-feeding:
When oxybutynin is used during lactation, a small amount is excreted in mother's milk. Use of oxybutynin during breast feeding is therefore not recommended.
4.7 Effects on ability to drive and use machines
Oxybutynin may cause drowsiness or blurred vision. Patients should be cautioned regarding activities requiring mental alertness such as driving, operating machinery or performing hazardous work while taking this drug.
4.8 Undesirable effects
List of adverse reactions:
Very common (>1/10); common (>1/100 to <1/10); uncommon (>1/1,000 to <1/100); rare (>1/10,000 to <1/1,000); very rare (<1/10,000), not known (cannot be estimated from the available data).
Infections and infestations
Not known: urinary tract infection
constipation, nausea, dry mouth diarrhoea, vomiting
Very common: Common: Uncommon: Not known:
abdominal discomfort, anorexia, decreased appetite, dysphagia gastroesophageal reflux disease
Psychiatric disorders Common: confusional state
Not known: agitation, anxiety, hallucinations, nightmares, paranoia, cognitive
disorders in elderly
Nervous system disorders
Very common: dizziness, headache, somnolence Not known: cognitive disorders, convulsions
Cardiac disorders
Not known: tachycardia, arrhythmia
Injury, poisoning and procedural complications Not known: heat stroke
Eye disorders Common: dry eyes
Not known: angle closure glaucoma, mydriasis, ocular hypertension, vision
blurred
Renal and urinary disorders Common: urinary retention
Vascular disorders Common: flushing
Skin and subcutaneous tissue disorders Very common: dry skin
Not known: angioedema, rash, urticaria, hypohidrosis, photosensitivity
Immune system disorders Not known: hypersensitivity
Other frequently reported side effects (>1 %) to oxybutynin are: facial flushing and difficulty in micturition. The incidence of facial flushing is more marked in children than adults. The occurrence of these effects may be reduced by lowering the dose. Excitatory CNS symptoms may occur during therapy with oxybutynin including restlessness, hallucinations, disorientation and convulsions. Children may be more liable to such effects.
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
The symptoms of overdosage with oxybutynin progress from an intensification of the usual adverse effects of CNS disturbances (from restlessness and excitement to psychotic behaviour), circulatory changes (flushing, fall in blood pressure, circulatory failure etc), respiratory failure, paralysis and coma.
Measures to be taken are:
1) immediate gastric lavage
2) physostigmine by slow intravenous injection
Adults: 0.5 to 2.0 mg i.v. slowly, repeated if necessary, up to a maximum of 5 mg. Children: 30 pg/kg i.v. slowly, repeated if necessary, up to a maximum of 2 mg.
Fever should be treated symptomatically with tepid sponging or ice packs.
In pronounced restlessness or excitation, diazepam 10 mg may be given by intravenous injection, tachycardia may be treated with intravenous injection of propranolol, and urinary retention can be managed by catheterisation.
In the event of progression of the curare-like effect to the paralysis of the respiratory muscles, mechanical ventilation will be required.
5 PHARMACOLOGICAL PROPERTIES
5.1 Pharmacodynamic properties
Oxybutynin hydrochloride is a synthetic, tertiary amine with an anticholinergic and antispasmodic (papaverine-like) effect on smooth muscle. Oxybutynin has both direct antispasmodic action on the smooth muscle of the bladder detrusor as well as anticholinergic action in blocking the muscarinic effects of acetylcholine on smooth muscle.
These properties cause relaxation of the detrusor muscle of the bladder and in patients with an unstable bladder, oxybutynin increases bladder capacity and reduces the incidence of spontaneous contractions of the detrusor muscle.
5.2. Pharmacokinetic Properties
Following oral administration, oxybutynin hydrochloride is rapidly absorbed from the gastrointestinal tract. Following a single dose of 5 mg p.o. peak plasma concentrations of 8 ng/ml were reached in less than 1 hour. The spasmolytic effect begins after 30 - 60 min, reaches a maximum level after 3 -6 hours and the effect lasts for a total of 6 - 10 hours. Oxybutynin is subject to an extensive first-pass effect. The bioavailability of orally administered oxybutynin hydrochloride is 2 % - 11 %.
Elimination is mainly by means of extensive hepatic metabolism (predominantly hydrolysis to 2,3-cyclohexylphenyl-glycolic acid and 4-hydroxy-cyclohexyl-phenylglycolic acid and de-ethylation). Cytochrome P 3A4 is involved in the metabolism of oxybutynin hydrochloride. Depending on the individual disposition, there can be considerable inter individual fluctuations in oxybutynin metabolism. The main metabolites are the inactive metabolite 2,2-phenylcyclohexylglycolic acid and the active metabolite N-desethyloxybutynin, which possesses comparable pharmacological activity to oxybutynin.
Elimination of oxybutynin is biphasic. The elimination half-life is 1 - 2 hours. The elimination half-life of the metabolite N-desethyloxybutynin is 2 - 3 hours. No accumulation occurs with repeated administration.
In elderly patients, the elimination half-life can be prolonged from 2 - 3 hours to 5 hours, due to increased bioavailability. Undesirable effects (side-effects) can thereby be intensified and may make a dose reduction necessary.
5.3. Preclinical Safety Data
Toxicological effects are solely increased pharmacological actions. Oxybutynin did not show mutagenic or carcinogenic effects.
In studies on embryonal toxicity heart defects and an increased incidence of skeleton anomalies (75mg/kg/day, rats) were observed in single cases.
6 PHARMACEUTICAL PARTICULARS
6.1 List of excipients
Lactose monohydrate, powdered cellulose, talc, magnesium stearate.
6.2. Incompatibilities
Not applicable.
6.3.
24 months.
6.4.
6.5
6.6
Nature and contents of container
Alu-Alu blister
HDPE bottles with PP closure and desiccant Pack sizes:
7, 14, 15, 20, 28, 30, 30x1, 56, 60, 98, 100, 120 gastro-resistant tablets (blister packs)
7, 14, 15, 20, 28, 30, 30x1, 56, 60, 100, 120 gastro-resistant tablets (HDPE bottles)
Not all pack sizes may be marketed.
Instruction for Use, Handling and Disposal
Not applicable
7
9 DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION
21/11/2005
10 DATE OF REVISION OF THE TEXT
30/05/2014