Oxybutynin is a medicine that relaxes an overactive bladder and reduces the need to urinate - read on for advice on its use, warnings and side effects.
Pharmacist - M.B.A. (Public Health) D.I.C.
What is oxybutynin used for? Urinary…
What is oxybutynin used for?
- Urinary incontinence, urgency and frequency in people with unstable bladder conditions. The condition may have no known cause (idiopathic bladder instability), or may be due to problems with the nerve supply to the bladder (neurogenic bladder), for example following a spinal cord injury, or as a result of conditions affecting the nervous system such as spina bifida or multiple sclerosis.
- Bedwetting (nocturnal enuresis) associated with an overactive bladder in children aged five years and over. Oxybutynin is used in combination with other non-drug therapy and only when other approaches have not been successful.
How does oxybutynin work?
- Oxybutynin hydrochloride is a type of medicine called an anticholinergic (or antimuscarinic) muscle relaxant. It works by relaxing the involuntary detrusor muscle that is found in the wall of the bladder.
- The detrusor muscle can sometimes contract in uncontrollable spasms, and this is often referred to as having an overactive or unstable bladder. The overactive detrusor muscle can cause an increase in the number of times you need to pass urine, uncontrollable urges to pass urine, or involuntary leakage of urine (urinary incontinence).
- By relaxing the detrusor muscle, oxybutynin reduces unstable, involuntary contractions of the bladder and thereby increases the capacity of the bladder to hold urine. This in turn reduces the need to pass urine.
How do I take oxybutynin?
- The dose of oxybutynin that is prescribed and how often to take it will vary from person to person. It is important to follow the instructions given by your doctor. These will also be printed on the dispensing label that your pharmacist has put on the medicine.
- Oxybutynin tablets and liquid can be taken either with or without food.
- If you forget to take a dose, take it as soon as you remember, unless it is nearly time for your next dose. In this case leave out the missed dose and take the next dose as usual when it is due. Do not take a double dose to make up for a missed dose.
- Keep taking this medicine as prescribed until your doctor tells you to stop.
What should I know before taking oxybutynin?
- Oxybutynin may cause drowsiness, dizziness and blurred vision. If affected do not drive or operate machinery.
- Oxybutynin may rarely cause the pressure in your eyeball to increase. Contact your doctor immediately if you experience eye pain or a sudden change in your eyesight while taking oxybutynin, for example a reduced ability to see fine detail, seeing haloes around lights or blurred vision.
- Oxybutynin may reduce sweating, which can make you more likely to overheat in hot environments, or if you have a high temperature (fever). Discuss ways to minimise this risk with your doctor or pharmacist.
- Oxybutynin is not licensed for use in children under five years of age and for this reason the leaflets provided with the medicine will say that the medicine is not recommended for children under five. However, specialists do sometimes prescribe oxybutynin off-licence to treat certain urinary problems in children. If your child has been prescribed this medicine and you want further information you should ask your doctor or pharmacist.
Who should not take oxybutynin?
- People with an obstruction to the outflow of urine from the bladder and difficulty passing urine (urinary retention).
- People with a blockage in the stomach or intestines, or inactivity in the intestines that prevents material moving through the gut (gastrointestinal obstruction, intestinal atony or paralytic ileus).
- People with severe inflammation of the bowel and back passage (ulcerative colitis).
- People with a sudden expansion of the large intestine seen in advanced ulcerative colitis or Crohn's disease (toxic megacolon).
- People with closed angle glaucoma.
- People with a condition called myasthenia gravis in which there is abnormal muscle weakness.
- People with rare inherited disorders called porphyrias.
- Oxybutynin tablets and liquid should not be used if you are allergic to any of their ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop taking oxybutynin and inform your doctor or pharmacist immediately.
Oxybutynin should be used with caution in
- Elderly people.
- People with kidney or liver problems.
- People with gastro-oesophageal reflux, eg due to a hiatus hernia.
- People taking medicines that can cause or worsen reflux oesophagitis, eg bisphosphonates such as alendronate.
- People who are constipated.
- Men with an enlarged prostate gland (benign prostatic hyperplasia).
- People with an overactive thyroid gland (hyperthyroidism).
- People with high blood pressure (hypertension).
- People with heart disease, such as heart failure, an irregular heartbeat (arrhythmia), fast heart rate (tachycardia) or angina.
- People with disorders of the involuntary nervous system (autonomic neuropathy).
Can I take oxybutynin while pregnant or breastfeeding?
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of oxybutynin for use during pregnancy has not been established. It is not recommended for use during pregnancy, unless the potential benefits to the mother outweigh any possible risks to the developing baby. Seek medical advice from your doctor.
- The safety of oxybutynin for use during breastfeeding has not been fully established. It is not recommended for use by breastfeeding mothers. Seek further medical advice from your doctor.
What are the possible side effects of oxybutynin?
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with oxybutynin. Just because a side effect is stated here, it does not mean that all people taking oxybutynin will experience that or any side effect.
Very common (affect more than 1 in 10 people)
- Feeling sleepy.
- Blurred vision.
- Feeling sick.
- Dry mouth.
- Dry skin.
Common (affect between 1 in 10 and 1 in 100 people)
- Dry eyes.
- Inability to empty the bladder.
Uncommon (affect between 1 in 100 and 1 in 1000 people)
- Abdominal discomfort.
- Loss of appetite.
- Difficulty swallowing.
Frequency not known
- Heartburn or indigestion (acid reflux).
- Difficulty passing urine.
- Urinary tract infection.
- Feeling anxious or agitated.
- Seeing or hearing things that are not really there (hallucinations).
- Feeling disorientated.
- Problems with learning, memory, understanding or problem solving.
- Convulsions (fits).
- Reduced sweating. See above.
- Heat stroke.
- Skin reactions such as rash, itching or increased sensitivity to sunlight.
- Faster than normal heartbeat (tachycardia).
- Irregular heartbeat (arrhythmias).
- Dilated pupils.
- Raised pressure in the eye (narrow angle glaucoma).
Talk to your doctor, nurse or pharmacist if you want any more information about the possible side effects of oxybutynin.
Can I take oxybutynin with other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with oxybutynin. Similarly, check with your doctor or pharmacist before taking any new medicines while taking oxybutynin, to make sure that the combination is safe.
There may be an increased risk of side effects such as dry mouth, blurred vision, drowsiness, constipation and difficulty passing urine if oxybutynin is taken with other medicines that can have antimuscarinic effects, such as the following:
- anticholinergic medicines for Parkinson's symptoms, eg procyclidine, orphenadrine, trihexiphenidyl
- antipsychotic medicines, eg haloperidol, chlorpromazine, clozapine
- antispasmodic medicines, eg hyoscine, atropine
- other anticholinergic medicines for urinary incontinence, eg tolterodine, solifenacin, propiverine
- MAOI antidepressants, eg phenelzine, tranylcypromine
- sedating antihistamines, eg brompheniramine, chlorphenamine, hydroxyzine
- tricyclic antidepressants, eg amitriptyline, clomipramine.
- Oxybutynin may reduce the absorption of levodopa (used for treating Parkinson's disease) from the gut.
Oxybutynin may oppose the effects of the following medicines on the gut:
If oxybutynin is used in combination with medicines that work by increasing the action of acetylcholine, such as those listed below, these medicines may oppose each other's effects:
- donepezil, galantamine or rivastigmine used to treat Alzheimer's disease
- neostigmine, distigmine or pyridostigmine used for myasthenia gravis
If you experience a dry mouth while taking oxybutynin you may find that medicines that are designed to dissolve and be absorbed from under the tongue, eg sublingual glyceryl trinitrate (GTN) tablets for angina, become less effective. This is because the tablets do not dissolve properly in a dry mouth. To resolve this, drink a mouthful of water before taking sublingual tablets.