What are Kentera patches used for?

• Urinary incontinence, urgency and frequency in adults 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.

How do Kentera patches work?

• Kentera patches contain the active ingredient oxybutynin hydrochloride, which is a type of medicine called an anticholinergic (or antimuscarinic) muscle relaxant. It works by relaxing the involuntary muscle that is found in the wall of the bladder.
• The muscle in the wall of the bladder is called the detrusor muscle. It 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.
• Kentera patches are applied to the skin of the hip, abdomen or buttock. The oxybutynin is steadily absorbed from the patch through the skin into the bloodstream. The patches are designed to be changed twice a week (every three to four days).

How do I use Kentera patches?

• One Kentera patch should be applied twice a week (every three to four days). You should always change your patch on the same two days each week, eg Monday and Thursday.
• The patches should be applied to a clean, dry, unbroken, non-irritated area of skin on the hip, abdomen or buttock.
• Don't stick the patch on straight after a hot bath or shower, wait for the skin to cool down first. Don't use talc, creams or moisturisers before applying the patch as they may prevent it sticking. The patches should be worn underneath your clothing and should not be exposed to the sun, eg when sunbathing. Avoid putting the patch on areas where it may be rubbed by tight clothing, eg waistbands.
• You should only wear one Kentera patch at a time. Each patch should worn for three to four days and then removed. The new patch should be applied to a different place on the hip, abdomen or buttock, and you should avoid using the same site for seven days.
• Kentera patches should not be divided, cut or damaged in any way.
• You can exercise, shower, bath and swim while wearing the patch, as long as you don't rub the patch when washing. However, avoid soaking for long periods in a hot bath as this may make the patch come unstuck.
• Removed Kentera patches should be folded in half, sticky side innermost, and placed inside the open sachet or a piece of tin foil, for careful disposal away from children. Do not flush used patches down the toilet. Used patches may still contain some active ingredient that may be harmful to children or the aquatic environment.
• If you forget to change your Kentera patch on your usual day, remove the old patch as soon as you remember and apply a new one to a new spot on your abdomen, hips or buttocks. You should then change this new patch on the same day you would usually change it, even if you have worn it for less than three or four days.

What should I know before using Kentera patches?

• 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 using this medicine, for example a reduced ability to see fine detail, seeing haloes around lights or blurred vision.
• Oxybutynin may reduce sweating, which can increase your susceptibility to overheat in hot environments, or if you have a high temperature (fever). Discuss ways to minimise this risk with your doctor or pharmacist.

Who should not use Kentera patches?

• Children and adolescents under 18 years of age.
• 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 blood disorders called porphyrias.
• Kentera patches 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 using Kentera patches and inform your doctor or pharmacist immediately.

Kentera patches 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 use Kentera patches while pregnant or breastfeeding?

• The safety of  oxbutynin for use during pregnancy has not been established. Kentera patches 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. The manufacturer states that Kentera patches are not recommended for use in breastfeeding mothers. Seek further medical advice from your doctor.

What are the possible side effects of Kentera patches?

• Itching at the patch application site.
• Dry mouth.
• Constipation.
• Diarrhoea.
• Headache.
• Dizziness.
• Blurred vision.
• Feeling sleepy.
• Feeling sick.
• Abdominal pain.
• Urinary tract infection.
• Skin reaction at patch application site, such as redness or rash.

Can I use Kentera patches 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 Kentera patches. Similarly, check with your doctor or pharmacist before taking any new medicines while using Kentera, 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 Kentera patches are used in combination with other medicines that can have anticholinergic effects, such as the following:

• amantadine
• anticholinergic medicines for Parkinson's symptoms, eg procyclidine, orphenadrine, trihexiphenidyl
• antipsychotic medicines, eg haloperidol, chlorpromazine, clozapine
• antispasmodic medicines, eg hyoscine, atropine
• codeine
• disopyramide
• 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:

• cisapride
• domperidone
• metoclopramide.

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
• pilocarpine.

If you experience a dry mouth as a side effect of Kentera patches 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.

References:

https://www.scottishmedicines.org.uk/medicines-advice/oxybutynin-39mg24h-transdermal-patch-kentera-fullsubmission-19005/

https://www.netdoctor.co.uk/medicines/liver-kidney-urinary-system/a6841/kentera-patches-oxybutynin/

https://www.medicines.org.uk/emc/product/6411/smpc

https://www.medicines.ie/medicines/kentera-oxybutynin-transdermal-patch-32573/smpc

https://www.ema.europa.eu/en/documents/overview/kentera-epar-summary-public_en.pdf

https://www.drugs.com/uk/kentera.html