Bladder Anti-Spasmodic Injections
Anti-Spasmodics for the overactive bladder
Recent evidence has shown that preparations of anti-spasmodic agents can be very effective in treating overactive bladder and detrusor instability. There are differences in the activity of units in different preparations.
Relief from the symptoms of overactive bladder last about 6 months with a range of 4-9 months. Treatment will need to be repeated on an ongoing basis to have continuation of symptom relief.
Commercially available preparations of anti-spasmodic agents include:
- Botox™ (onabotulinum toxin A).
- Dysport™ (abobotulinumtoxin A).
- *Xeomin™ (incobotulinum toxin A).
- *Myobloc™ (rimabotulinumtoxin B).
There is very little data on these preparations.
How do anti-spasmodic agents work?
Acetylcholine is the principle neurotransmitter at the presynaptic terminal of nerves in the parasympathetic nerve system. Anti-spasmodics prevents the presynaptic release of acetylcholine into the nerve terminal. Thus, acetylcholine is prevented from acting on postsynaptic receptors resulting in complete or partial paralysis of the muscles supplied; in this case, the detrusor muscle primarily responsible for bladder contractility.
Other mechanisms of action:
- Mediation of the intrinsic and spinal reflexes thought to cause neurogenic detrusor overactivity.
- Modification of efferent (motor) pathways.
Symptoms and outcomes that have been shown to be improved by anti-spasmodics include:
- Reduction in urinary frequency and nocturia.
- Reduction in continence pad use.
- Increase in quality of life outcome measures.
- Increase in bladder capacity.
- Reduction in urinary urgency and urgency incontinence.
Indications for bladder anti-spasmodic treatment
- Neurogenic detrusor overactivity.
- Non-neurogenic detrusor overactivity.
Failure to respond to or tolerate therapies including:
- Pelvic floor retraining
- Selective beta 3-adrenoceptor agonist (Betmiga)
- Bladder hydrodilatation
The absence of:
- Myasthenia gravis or Eaton-Lambert Syndrome
- An active or untreated bladder infection
- Know allergy to Botulinum Toxin A
Side-effects associated with bladder anti-spasmodic treatment:
- Urinary tract infection (17%).
- Inability to empty bladder (temporary; 10%).
- Erythema multiforme.
- Generalised weakness.
What does anti-spasmodic treatment involve?
Surgery can take place as an;
- Office procedure
- Day case procedure
- In patient procedure
The anti-spasmodic is administered via the operating channel of a cystoscopy. The cystoscope used can be a:
- Flexible or
- Rigid cystoscopy
but needs to have an operating channel.
- Oral antibiotics from 3 days prior to procedure.
- Intravenous antibiotics at time of surgery.
- Oral antibiotics for 3 days after procedure.
- The recommended dose is 100 Units of anti-spasmodic agent.
- The recommended dilution is 100 Units/10 mL with 0.9% non-preserved saline solution.
- Reconstituted anti-spasmodic (100 Units/10 mL) is injected into the detrusor muscle via a flexible or rigid cystoscope, avoiding the trigone.
- The needle is inserted approximately 2 mm into the detrusor, and 20 injections of 0.5 mL each (total volume of 10 mL) are spaced approximately 1 cm apart.
After the injections have been completed, the bladder is observed to ensure that there is no excessive bleeding taking place. The bladder is then emptied.
After the injections are given, patients are required to demonstrate their ability to void prior to being discharged. The patient is observed for at least 30 minutes post-injection and until a spontaneous void has occurred.
Patients are considered for reinjection when the clinical effect of the previous injection has diminished, but no sooner than 12 weeks from the prior bladder injection.