Intravesical Gentamicin Treatment

Introduction

This leaflet provides information about gentamicin administration directly into the bladder (i.e. intravesical administration). It will cover the indication, duration, clinical benefits and possible side-effects of therapy.

What is intravesical Gentamicin and what is it used for?

Gentamicin is an antibiotic used to treat and prevent infection caused by bacteria in the urinary system.

You have been prescribed gentamicin for the management of recurrent urinary tract infections. It will be administered via the intravesical route (i.e. instilled directly into the bladder via a catheter) rather than into a vein, the route used for acute or severe infections causing symptoms such as fevers. Your Consultant Urologist will have explained this to you prior to starting therapy.

What are the benefits of intravesical gentamicin treatment?

Administering gentamicin directly into the bladder means that it works directly at the site of infection.

As gentamicin is not administered/circulating in the bloodstream, other advantages include:

• Prevention of some common side-effects (e.g. nausea, vomiting, diarrhoea)
• No need for regular monitoring of blood gentamicin levels, which requires a blood test
• Being trained and assessed to self-administer intravesical gentamicin in the comfort of your own home, if you are able to do this

The aim of treatment is to reduce the need for hospital admission (to receive antibiotics via a vein) and to reduce how often you get UTIs.

What are the alternatives to this treatment?

Your doctor will already have tried other preventative measures and treatments to reduce your risk of urinary infection. Intravesical gentamicin is used if other treatments for recurrent urinary tract infections have been unsuccessful in improving your symptoms and preventing recurring urinary infections, such as long-term use of low dose oral antibiotics, oral agents such as Hipprex and D-mannose, use of cranberry capsules, and increased oral fluid intake. Alternative bladder instillations which can be used are Hyacyst (sodium hyaluronate) and iAluril (sodium hyaluronate and chondroitin sulphate).

Before starting intravesical gentamicin

Please inform your Urology Consultant / Urology nurse if you think you have any of the following as you will not be given gentamicin if:

• You are allergic (hypersensitive) to gentamicin
• You have myasthenia gravis (this is a disease that causes muscle weakness)

You will be tested for an active urine infection with a urine sample dipstick test. If this is strongly positive for infection you will be given a course of antibiotic treatment and the gentamicin treatment will be rescheduled

Please also inform your consultant/nurse if:

• You are pregnant, may be pregnant or are planning to have a baby
• You are breastfeeding, or planning to breastfeed
• You have any muscle weakness problems
• You experience severe diarrhoea
• You develop severe skin reactions
• You know (or think) you have a mitochondrial disease (certain conditions may increase risk of hearing loss with this antibiotic)

How is intravesical gentamicin given?

The dose of gentamicin (80mg) is diluted to 50ml with sterile sodium chloride 0.9%. This solution is then administered directly into the bladder (intravesical) using a small, thin, single-use catheter. It is then left in the bladder, ideally overnight if you are using this at home, or for as long as possible if you have attended a urology clinic for the treatment (with the aim of retaining the treatment for a minimum of one hour). You would be advised to reduce your fluid intake for 1 hour before and after the treatment to reduce the need to pass urine whilst the treatment is in the bladder. After this time, it is passed out of the body when you next urinate. It can also be removed using clean intermittent catheterisation, if you use a catheter to empty your bladder.

How long is the course of treatment?

You should expect to receive intravesical gentamicin for a total of 24 weeks. This will include 11 instillations overall, at the following frequency:

• Weekly for 4 weeks
• Fortnightly for 8 weeks
• Monthly for 12 weeks

Administration will initially be done in clinic by a urology CNS (clinical nurse specialist). You will then continue to attend clinic for your treatment, or you will receive teaching to support self-administration of intravesical gentamicin in your own home. You may have already had similar teaching for previous therapies (e.g. iAluril). The urology nurse will make sure you are confident with self-administration of intravesical gentamicin and provide you with all the equipment required.

Prescriptions for gentamicin will be written in your clinic appointments and supplies will be made from Addenbrooke’s Outpatient Pharmacy.

Monitoring

Routine monitoring of gentamicin levels is not required as it is not being administered directly to the bloodstream. Any blood monitoring performed will be at the discretion of your treating consultant.

Possible side effects of Intravesical Gentamicin

Like all medicines, gentamicin can cause side effects, although these are very rare and not everybody gets them. Intravesical gentamicin is well-tolerated by most patients. However, some patients may develop significant side effects. These include:

• Local irritation of the bladder lining. If you experience discomfort or notice blood in your urine, please contact the urology CNS.
• Dizziness or ringing in the ear (Tinnitus). This risk is reduced as gentamicin is not being administered directly into the bloodstream, but please seek medical attention if you notice these symptoms or worsening of existing symptoms. You may need a blood test to check gentamicin levels.

Contacting us

If you have any further questions or need advice, please contact:

• Indira Horil Roy Urology Clinical Nurse Specialist 01223 274 608
• Ellen Gunaseelan Urology Clinical Support Nurse 01223 274 608

MyChart

We would encourage you to sign up for MyChart. This is the electronic patient portal at Cambridge University Hospitals that enables patients to securely access parts of their health record held within the hospital’s electronic patient record system (Epic). It is available via your home computer or mobile device

More information is available on the My Chart section of our website.