Instructions
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Clinical Pearl We are now going to examine some of the pharmacological treatment options. However, it should be noted that when possible both pharmacological and non-pharmacological treatment options should be used concurrently.
Pharmacological Options
Antimuscarinic
agents
Alpha-adrenergic
antagonist
Beta-3
adrenergic agonist
Botulinum
toxin A
Antimuscarinic or anticholinegic agents are recommended by the Agency for Health Research and Quality (the AHRQ), formerly known as the Agency for Health Care Policy and Research (the AHCPR), as the first line of therapy for UUI and OAB. How these medicines work is interesting. They interfere with impulses from the parasympathetic nerves that cause the detrusor muscle of the bladder to contract. This causes the detrusor muscle to relax and the receptors responsible for bladder contraction to be inhibited. Drug class options are listed above. Antimuscarinics
Antimuscarinics
are used to address the following four issues:
1. Inhibiting overactive detrusor contractions 2. Increasing bladder capacity and the time between each void 3. Decreasing day and nighttime voiding frequency 4. Decreasing the number of urge urinary incontinence episodes The actions of antimuscarinics are shown below as reported by Paul Taylor in 2005. (Taylor, P. Pharmacologic Management of Overactive Bladder. JWOCN. Supplement 1.2005;32:516-523) UUI episodes decreased from 40-70% for those with wet OAB. These muscarinic receptors are found throughout the body and contribute to unwanted adverse effects experienced. These adverse effects are more problematic in the elderly and occur more frequently and tend to be more severe. Contraindications for these types of medications include urinary and gastric retention and uncontrolled narrow-angle glaucoma. Adverse Effects of Antimuscarinics
Dry
mouth
Constipation
Blurred
vision
Sedation
Cognitive
impairment
EKG
changes
Decreased
sweating
Dry mouth in addition to being bothersome can contribute to tooth decay and poor fitting dentures. Chronic use of these medications can cause tooth loss and tooth decay as well. Constipation can increase the risk of UTIs due to incomplete bladder emptying, and increase the risk of bladder prolapse in women. Blurred vision and sedation have significant safety implications in terms of accidents and injuries while walking or driving. Cognitive impairment may manifest as acute confusion (delirium), short term memory impairment or nightmares. EKG changes most commonly are related to Q-T interval prolongation (this is the interval between the start of the Q wave and the end of the T wave in the hearts electrical cycle). Decreased sweating can be quite dangerous in the summer months and contribute to hyperthermia. It is a good idea to teach your clients that these medications take a couple of weeks before an effect is seen.
Antimuscarinics seen in your clinical practice
Darifenacin
(Enablex)
Oxybutynin
(Ditropan, Oxytrol)
Solifenacin
(VESIcare)
Tolterodine
(Detrol)
Trospium
(Sanctura)
The drugs listed are all available in tablet form. Oxybutynin also comes in a transdermal patch, a 10% gel, a bladder instillation solution and an OTC formulation. And all of these, with the exception of Trospium, are metabolized via the cytochrome P450 system and may contribute to adverse drug-drug interactions. It is thought that Trospium, since it is eliminated unchanged, may have a lower potential for drug-drug interactions. It is more water soluble and is less likely to cross the blood brain barrier. Of note, there are fewer complaints of dry mouth with topical Oxybutynin than the oral formulation. Rick Fields-Gardner |
