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Other Topics EXAM 3
Other Topics EXAM 3 - Ruscin Urinary Incontinence
33
Pharmacology
Graduate
04/17/2012

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Term
urinary incontinence
Definition
the involuntary loss of urine severe enough to have social and/or hygienic consequences - not a disease, but a symptoms with many causes

10 million Americans suffer from UI

15-35% of community dwelling elderly and 50+% of nursing home residents suffer from UI

costs conservatively $16 billion annually

UI is NOT a normal consequence of aging

UI is underdiagnosed due to patient reluctance to report

prevalence rates are twice as high in women as in men
Term
risk factors for UI (not well defined)
Definition
immobility

gender

parity

UTIs

menopause

GU surgery

lack of postpartum exercise

various medications

**NOT CHRONIC BACTERIURIA OR AGE**
Term
clinical, psychological, and social impact
Definition
rashes

pressure sores

skin and urinary tract infections

odor

restriction of activity

embarrassment, isolation, depressive symptoms

sexual dysfunction

instituionalization
Term
UI physiology
Definition
lower urinary tract is a high volume, low pressure system

intravesicular pressure = bladder volume

intraabdominal pressure

detrusor tone

intraurethral pressure

to maintain continence, intraurethral pressure must exceed intravesicular pressure
Term
stress incontinence
Definition
dysfunction of the bladder outlet (urethral sphincter weakness) leading to transient loss of small amounts of urine when intra-abdominal pressure increases

coughing, laughing, sneezing, bending, lifting

posterior urethrovesicular angle changes (parity, surgery)

strength or responsiveness of urethral sphincter

patients often dry at night
Term
detrusor instability/overactive bladder (OAB) and urge incontinence
Definition
most common type (70%); unstable bladder, spastic bladder

CNS dysregulation, stroke, PD, AD, neoplasm, NPH

hyperreflexia of afferent pathways

deconditioned voiding reflexes

clinical features: urgency, frequency, nocturia, frequent small volume voiding

no characteristic features on physical exam, although CNS dysfunction may be apparent
Term
overflow incontinence
Definition
occurs when intravesicular pressures exceed intraurethral pressures - ONLY at HIGH volumes

bladder outlet obstruction - BPH, neoplasm

impaired afferent sensation

diabetic neuropathy (bladder doesn't empty completely), spinal cord lesions below T-11

muscle relaxants, calcium channel blockers, anticholinergics

clinical features: palpable or percussable bladder, suprapubic tenderness, lower urinary flow rates, post-void residual urine
Term
functional incontinence
Definition
the inability of a normally continent person to reach the toilet in time to avoid an accident

musculoskeletal limitation - joint pain, arthritis, muscle weakness

unfamiliar setting, lack of conventional toilet facilities

clinical features: accidents on the way to the toilet and early morning incontinence are suggestive of this type
Term
iatrogenic incontinence
Definition
may aggravate or unmask above causes

potent fast acting diuretics - lasix

sedative hypnotics, neuroleptics

muscle relaxants

alpha1 agonists - PPA, pseudoephedrine
pinch the urethra bladder neck = overflow incontinence

alpha1 antagonists - terazosin, prazosin
in females relax the urethra sphincter; beneficial in males with BPH

anticholinergics
parasympathetic innervation = contraction of bladder
parasympathetic antagonism = relaxation of bladder

calcium channel blockers
Term
UI evaluation and diagnosis
Definition
medial history/labs/urodynamics

urinary complaints (frequency, low flow)

MMSE, depression screening

glucose, urinalysis, urine culture

post void residual (PVR)

cystometry
volume at first contraction
maximal cystometric capacity

urinary flow measurement

urethral pressure profile

imaging studies - IVP (intravenous pyelogram) to look for physical barriers
Term
post void residual (PVR)
Definition
amount of urine remaining in the bladder following attempt by the patient to empty the bladder

normal < 50 mL

increased > 50 mL

KNOW THE CUTOFFS

assessed by straight catheter placement post void or estimated with bladder scanner
Term
UI physical exam
Definition
abdominal, pelvic, rectal, neurological

rectal exam to rule out fecal impaction, BPH

pelvic exam - atrophic vaginitis

neurological damage (upper motor neurons)

abdominal tenderness (overflow incontinence)
Term
goals of urinary incontinence management
Definition
goals should be individualized based on underlying disease states and disabilities

reduce wetting episodes

improve ADLs and QOL

reduce complications such as falls, pressure ulcers, and pharmacologic ADRs

reduce caregiver burden

reduce cost of direct and indirect continence care

cure or diminish UI and its symptoms, including physical discomfort from UI or comorbid conditions
Term
UI non pharmacologic treatments
Definition
scheduling regiments/timed voiding

prompted voiding

bladder training

pelvic floor exercise/Kegel exercises

vaginal weight training

biofeedback

pessaries/bladder neck support prostheses

[image]

NOTE: you will achieve MUCH better results controlling incontinence symptoms when behavioral interventions are used in combination with medication therapies. medications alone have been shown to be of minor benefit when used alone, especially in patients in nursing home settings

CAUTION: any drug used to treat incontinence can make it worse if the diagnosis is wrong or the patient has more than 1 type of incontinence
Term
treatment of stress incontinence
Definition
aim: increase resistance to sudden increases in intra-abdominal pressure

Kegal exercises

topical estrogens for atrophic vaginitis

pseudoephedrine 15 to 60 mg TID
pinches the neck of the bladder
ADR: dizziness, increased BP, insomnia, HA
contraindications: HTN, arrhythmias, MI/CAD, hyperthyroidism


duloxetine (Cymbalta) - dual inhibitor of serotonin and NE
FDA approved in 2004 for depression and diabetic neuropathy
not FDA approved for stress incontinence
40-80 mg/day in 1-2 doses has been shown to improve symptoms of stress incontinence in several studies
ADRs: HA, insomnia, constipation, dry mouth, dizziness, fatigue, increased BP
reserved for patients with other underlying conditions (concurrent depression or neuropathy)
Term
treatment of overflow incontinence
Definition
aim: to improve complete bladder drainage

prazosin 1-5 mg BID to TID

terazosin 1-10 mg HS

doxazosin 1-8 mg HS

phenoxybenzamine 10 mg QD-TID
ADRs: hypotension, tachycardia, impotence

bethanechol 10 mg TID
ADRs: diarrhea, flushing, cramping
cholinergic agonist = contraction of the bladder
used for a patient with atonic bladder (long standing diabetes)

5 alpha reductase inhibitors (finasteride, dutasteride)
Term
acute urinary retention (AUR)
Definition
painful

initial management by catheterization (often in ER setting)

refractory urinary retention may require surgical intervention
Term
American Urological Association - Symptom Index (AUA-SI)
Definition
scale: 0 (not at all) to 5 (almost always)

symptoms:

incomplete emptying

frequency

intermittency

urgency

weak stream

straining

nocturia
Term
alpha blockers for BPH
Definition
TERAZOSIN (HYTRIN)

MOA: long acting alpha1 blocker

t1/2 = 12 hours

time to onset: days to weeks

recommended HS

non selective, will also lower BP

titration required

possible interactions with PDE5 inhibitors

DOXAZOSIN (CARDURA)

MOA: long acting alpha1 blocker

t1/2 = 22 hours

time to onset: days to weeks

non selective, will also lower BP

titration required

possible interactions with PDE5 inhibitors

TAMSULOSIN (FLOMAX)

MOA: long acting alpha1a blocker

t1/2 = 9-15 hours

time to onset: days

recommended ~30 minutes after same meal each day

selective - relaxes the urethra and prostate tissue, but does NOT lower BP

titration may or may not be required

possible interactions with PDE5 inhibitors

ALFUZOSIN (UROXATRAL)

MOA: long acting alpha1 blocker

t1/2 = 9 hours

time to onset: days

recommended with same meal each day

titration not required

should not be administered with potent 3A4 inhibitors (ketoconazole)

possible interactions with PDE5 inhibitors

SILODOSIN (RAPAFLO)

MOA: long acting alpha1a blocker

t1/2 = 13.5 hours

time to onset: days

recommended with same meal each day

selective - relaxes the urethra and prostate tissue, but does NOT lower BP

titration not required

possible interactions with PDE5 inhibitors

inhibitors of 3A4 and Pgp increase exposure

according to the AUA guidelines, the alpha blockers are "similarly effective"; however the ADRs appear slightly different
Term
treatment of detrusor instability (OAB)
Definition
aim: eliminate or reduce uninhibited detrusor contractions

anticholinergics:
decrease detrusor contractions
increase bldder capacity
decrease symptoms of urgency
ADRs such as dry mouth, constipation, cognitive impairment are common
study variables: urgency episodes, incontinence episodes, volume voided, volume at first contraction, maximal cystometric capacity
efficacy is similar between agents, difference is with the ADRs of the different anticholinergics

M3 and M2 muscarinic receptors predominate in the bladder

M3 is responsible for the contractions (stimulate M3 = contraction)

stimulate M2 = relax the bladder

enablex and vesicare are considered M3 selective drugs; the predominant effect of these drugs are on the bladder (cause less constipation, dry mouth, and cognitive impairments)

oxybutynin (Ditropan) 2.5-5 mg BID-TID

oxybutynin XL (Ditropan XL) 5-30 mg QD

oxybutynin patch (Oxytrol) 3.9 mg 2x/week
doesn't have as many ADRs as the PO form

tolterodine (Detrol) 1-2 mg BID
metabolized by 2D6 to the active form (a portion of the population are 2D6 poor metabolizers)

tolterodine LA (Detrol LA) 2-4 mg QD

trospium chloride (Sactura) 20 mg QD-BID

solifenacin (Vesicare) 5-10 mg QD

darifenacin (Enablex) 7.5-15 mg QD

fesoterodine (Toviaz) 4-8 mg QD
prodrug that is metabolized outside the 2D6 system (serine esterases instead)
Term
treatment of detrusor instability (OAB):

oxybutynin
Definition
oral administration - DEO metabolite

DEO thought to be related to ADRs

DEO highest with oxybutynin IR
60-80% dry mouth

DEO lowest with oxybutynin patch/gel
10-15% dry mouth
bypass first pass metabolism

TRANSDERMAL OXYBUTYNIN

patch (matrix) - drug is mixed into the adhesive layer

dose delivery rate is 3.9 mg oxybutnin per day

patch placed on skin, drug passes through skin into bloodstream (bypass first pass metabolism)

administer 1 patch every 3-4 days
replaceing the patch the same 2 days each week (Sunday and Wednesday) may improve compliance

rotate application to abdomen, hip, or bottock

bathing should not affect adhesion

new oxybutynin gel product FDA approved (Gelnique)
Term
treatment of detrusor instability (OAB):

tolterodine
Definition
metabolized via 2D6 to active substance 5 hydroxy methyl tolterodine (5-HMT)

poor metabolizers may have poor response to tolterodine
Term
treatment of detrusor instability (OAB):

Sanctura (trospium chloride)
Definition
MOA: antimuscarinic

indication: OAB (urgency, frequency, UUI)

20 mg BID (20 mg QD is CrCl < 30 ml/min)

ADME:
<10% absorbed - empty stomach/1 hour before meals
mainly non-CYP450 metabolism

monitoring/side effects:
dry mouth, constipation, dyspepsia, headache

chemically it is polar so it cannot cross the BBB very well; less cognitive problems associated with Sanctura

possible interaction with drugs that may compete for renal tubular secretion: digoxin, morphine, metformin, vancomycin

cautions/contraindications: urinary retention, gastric retention, narrow angle glaucoma

FDA approval based on two 12 week trials
decrease in frequency vs. placebo
decrease in urge incontinence vs. placebo
increase in volume voided vs. placebo
Term
treatment of detrusor instability (OAB):

Vesicare (solifenacin)
Definition
MOA: antimuscarinic (M3 selective)

indication: OAB (urgency, frequency, UUI)

ADME:
well absorbed; with or without food
metabolism by 3A4 - inducers or inhibitors of 3A4 can alter kinetics

monitoring/ADRs: dry mouth, constipation, blurred vision, urinary retention, dry eyes

Vesicare can cause a lot of constipation (first studied as a drug for IBS)

cautions/contraindications: urinary retention, gastric retention, narrow angle glaucoma

3 fecal impaction/intestinal obstructions in trials

FDA approval based on four 12 week trials
decrease in frequency vs. placebo
decrease in urge incontinence vs. placebo
increase in volume voided vs. placebo
Term
treatment of detrusor instability (OAB):

Enablex (darifenacin)
Definition
MOA: antimuscarinic (M3 selective)

indication: OAB (urgency, frequency, UUI)

ADME:
bioavailability about 20% can be taken with or without food
metabolism via 2D6 and 3A4

monitoring/ADRs:
dry mouth, constipation, blurred vision, dyspepsia, abdominal pain

15 mg dose has a big jump in ADRs; 7.5 mg for older patients

cautions/contraindications: urinary retention, gastric retention, narrow-angle glaucoma

FDA approval based on four 12 week trials
decrease in frequency vs. placebo
decrease in urge incontinence vs. placebo
increase in volume voided vs. placebo

one study showed increased warning time

one study showed no effects on cognition; this study was done on patients with no cognitive problems (not studied in patients with cognitive problems or at risk for cognitive problems)
Term
treatment of detrusor instability (OAB):

Toviaz (fesoterodine)
Definition
MOA: antimuscarinic (non-selective)

indication: OAB (urgency, frequency, UUI)

dose: 4 mg QD, may increase to 8 mg QD
swallowed whole, do not crush or chew; with or without food
do not exceed 4 mg QD if taking 3A4 inhibitor or if CrCl < 30 ml/min

ADME:
metabolized by nonspecific esterases to 5-OH methyl tolterodine (active)
bioavailability 52%
active metabolite metabolized via 2D6 and 3A4 to inactive compounds

ADRs: dry mouth, constipation, blurred vision, dyspepsia, abdominal pain

no clinical advantage unless the patient is a poor metabolizer (2D6)
Term
effects of anticholinergic treatments for OAB
Definition
reduce incontinence episodes by > 50%

reduce frequency episodes by about 20%

increase bladder storage (volume voided)

decrease urgency episodes

may decrease nocturia
Term
anticholinergic ADRs of OAB treatments
Definition
dry mouth

dry eyes

constipation

urinary retention (if dose too high)

CNS/cognitive side effects

iris/ciliary body = blurred vision

lacrimal gland = dry eyes

salivary glands = dry mouth

heart = tachycardia

stomach = dyspepsia

colon = constipation

bladder = retention

muscarinic receptors are widely distributed throughout the body

in addition to the bladder, these receptors are located in a variety of organs of the parasympathetic nervous system, as well as in the CNS

common CNS ADRs are dizziness, somnolence, and impaired memory and cognition
Term
use of anticholinergic agents in patients with dementia/AD
Definition
cholinergic system is damaged in dementia and AD

those with dementia/AD are sensitive to cognitive impairment induced by drugs with anticholinergic properties

ADRs related to:
total anticholinergic "load"
baseline cognitive function
individual pharmacokinetic and pharmacodynammic variability

when appropriate, the goal is to eliminate the use of anticholinergic agents or substitute with an agent that has less anticholinergic effects
Term
roles of muscarinic receptor subtypes in the CNS
Definition
all 5 muscarinic receptor subtypes are expressed in the brain, and are located both pre and post synaptically on cholinergic neurons and on interneurons

M1
selective impairments of memory function
working memory, consolidation
M1 receptors play a critical role in modulating cognitive function

M2
learning and memory deficits; antagonists shown to enhance memory and facilitates recovery from brain injury
thought to be involved in inhibition of ACh release

M3
no major deficits in learning, memory, or cognitive function

M4
antagonists shown to enhance ACh levels in striatum

M5
no major deficits in learning, memory, or cognitive function
Term
passive and active efflux transport across the BBB
Definition
increased lipophilicity = increased diffusion

increased charge/polarity = decreased diffusion

decreased molecular bulkiness = increased diffusion

also present in the BBB are a number of protein transport systems, which act as either active efflux systems for certain molecules (P-glycoprotein (Pgp) pump) or mediate influx of nutrients
Term
comparison of antimuscarinic OAB medications' ability to cross BBB
Definition
unlike oxybutynin, tolterodine, and darifenacin, which are tertiary amines, trospium has a quaternary amine structure. as such, trospium has a highly positive charge, is hydrophilic in nature, and is not thought to cross the BBB under normal physiological conditions

darifenacine is selective for the M3 receptor subtype and is a known substrate for the Pgp efflux pump
Term
treatment of functional incontinence
Definition
aim: remove underlying cause - sedative hypnotic drugs

scheduled bathroom visits

bedside commode

assist with functional disabilities (walkers)
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