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Week 8
seminar
Urinary System Disorders and
Calculating ‘Desired-Doses’
(chapter-28 and chapter-9)
The Urinary System
 Made up of Organs which form & excrete urine
(see Fig.28-1 on pg 585)
 (2)
Kidneys
 (2)
Ureters

Bladder

Urethra
Common symptoms of Urinary
System Disorders
 Anorexia, Nausea, Vomiting
 Fatigue, Lethargy, Malaise
 Dysuria, urgency, frequency, hematuria
 Pain in lower-back (kidney area), flank (sides)
 Fever, disorientation
Common Side-effects of Rx’s for
Urinary System Disorders
 Drying of secretions
 Drowsiness, dizziness, sedation
 Rash, hives, ‘urticaria’
 GI effects (nausea, vomiting, diarrhea)
 Headache
 Discoloration of urine (see Table 28-1, p.585)
UrinarySystem DRUG therapy
 See Chart @ top of page-584 in Textbook
 Diuretics – modify kidney function
 Electrolytes/Fluids (“replacement therapy”)
(see Table 28-2 on page-586) … examples …
 Sodium
 Potassium
 Calcium
 Magnesium
… more detail, next slide
Electrolyte imbalance effects
Electrolyte
level
symptoms
SODIUM
high
Edema, thirst, high temp, flushing
low
Stomach-cramps, vomiting, diarrhea
high
Abdominal-distension, diarrhea
low
Paralysis, weakness, muscle function
high
Anorexia, nausea, coma, weakness
low
Muscle-cramp/twitching, numbness/tingling
of fingers, toes, lips
high
Flushing, sweating, low temp, cardiac
depression
low
Abnormal heart rhythms, neurotoxicity
POTASSIUM
CALCIUM
MAGNESIUM
Urinary Tract Infections (UTI)
 Most common bacterial infection in the U.S.
 10 – 20% of females have a UTI during
lifetime
 E.Coli causes ~90% of all cultured UTI’s
 Upper UTI (kidneys/ureters) - symptoms
include> *lower-back/flank pain *fever
*headache *nausea/vomiting
 Lower UTI (bladder/urethra) - symptoms
include> *frequency *urgency *dysuria
*hematuria *oliguria *incontinence
Some causes of UTI’s
 Anything that results in urine being ‘held’ in the
bladder (more common in females …sorry ladies!)
 If you gotta go … you BETTER go!
 Dietary factors – certain foods (see Box 28-1 p587)
 Enlarged Prostate (males) – constricts the
urethra, causing urine to be ‘retained’ in the
bladder
 Female ‘Plumbing’ – due to the short length of
urethra, and the proximity of the urethra, vagina,
and the anus
UTI - Drug Therapy
 Anti-Bacterials (sulfa-drugs, trimethoprim)
kill bacteria, in the urine and systemically
 Anti-septics (Macrobid, methenamine)
antibiotic activity ONLY in the urine !
 Analgesics (Pyridium, AZO-standard otc)
by topical and local anesthesia on the lining of
the urinary-tract
 --- Study --- Table 28-3 on page 589
UTI – RX patient ed
 Sulfonamides (sulfa-drugs) – take on
empty-stomach with a full glass of water
 Drink plenty of water throughout the day
(eight to ten 8-oz glasses if on a sulfa-drug)
 If taking sulfa-drug, avoid prolonged
exposure to sunlight, unless using a good
sunscreen !
 Complete entire course of UTI drug
treatment … even if symptoms improve !!!
More UTI-drug patient ed
 Pyridium (phenazopyridine) – changes urine
color to orange-red color! May stain clothing
 Cranberry juice, Vit-C, prunes make urine
more acidic, making antiseptics more effective
 Carbonated drinks, citrus fruits make urine less
acidic, making antiseptics less effective !
 FEVER after starting the drugs may be a sign of
a drug-reaction, not a UTI-symptom
 small, spastic-like bladder (‘tiny-tank’)
that empties automatically when filled
to a certain point
 Tofranil (imipramine) – anti-depressant
 DDAVP (desmopressin) – an anti-diuretic
that actually increases the reabsorption
of water -----available as a Nasal-spray,
or tablet
Time for
Calculating Doses
(oral, nonparenteral)
 the main 3 calculation methods
--- Ratio-and-Proportion
method
--- Formula-Method
--- Dimensional-analysis
 Choose the ONE method that you’re most
comfortable with … and stick with it !
Why go with ONE method ?
 …you will become very familiar
with your ‘chosen’ method
 … this will reduce the chance of
medication errors that may occur
from switching between calculation
methods !
Basic Rules for confident calculating
(see Box 9-1 on p.166 … dosage-forms)
 Always check UNIT’s (numerator/denominator)
 Always work the problem ON PAPER, even the
math seems EASY
 Check and RE-CHECK all Decimals, Fractions
 LOOK at the RESULT! …does it look reasonable,
does it make sense?
 Take ONE LAST LOOK to make sure you
calculated dose in the correct units
Box 9-1(p.166) Dosage-forms
 Know which types of dosage-forms can be
divided, halved, altered
 Scored tablets – okay to break
 Oral – syrups and liquids – okay to alter
 Timed-release (sustained, delayed) – DO NOT
BREAK or ALTER THESE ! … this can significantly
change the rate of the drug’s dissolution
(dissolving) and its absorption
“labeling” the parts of the
problem
 “DA” = dose-available, what is ‘on-hand’
 “DO” = dose-ordered, what you ‘want’
 “DF” = dosage-form, of the ‘on-hand’
 “DG” = dose-given, this is the unknown-amount
of the on-hand drug that we are calculating …
this is the ‘X’ that we are solving for.
Ratio-and-Proportion
 Units must match … numerator/denominator
 Ratio examples: 60-minutes/1-hour
 Proportion examples: 60min/1hr = 120min/2hr
 Let’s try one!: how many minutes in 2.5 hours ?
a) we are looking for
b) we know that
x minutes/2.5 hours
60min/hr (60min = 1hr, written as fraction)
… see next slide … )
(
Ratio-and-Proportion
 Let’s try one!: how many minutes in 2.5 hours ?
1st: we are looking for
x minutes/2.5 hours
2nd: we know that 60min/hr …(60min = 1hr, written as
fraction) so set-up the problem as xmin/2.5hr = 60min/hr
3rd: now we cross-multiply x-min x 1-hr = 2.5hr x 60min
4th: ‘hr’s cancel, leaving: x = (2.5)(60min) = 180 minutes …
our final answer, which makes sense! 2-1/2 hours is 60min +
60min + 30min = 180 minutes.
Formula - method
 “DA” = dose-available, what is ‘on-hand’
 “DO” = dose-ordered, what you ‘want’
 “DF” = dosage-form, of the ‘on-hand’
 “DG” = dose-given, this is the unknown-amount
of the on-hand drug that we are calculating
 Always check that the strengths of the drug-
ordered (DO) and the drug-available (DA) are in
the same-unit-of-measure!
Formula-method cont.
 Look at page-171
 Example #3, then Example #4
 Ask yourself … (also, page-171)
--what the Dr. ordered (DO)?
--what strength is available (DA)?
--what is the unit of measure (DF)?
--how much do we need to give (DG)?
 REMEMBER ! … 1-grain = 60-mg (gr i = 60 mg)
Dimensional - analysis
 Look at page-173 of Textbook
 Once learned, this is a very good system
 Try a few examples in your Textbook
 May be the ‘one for you’ !
QUESTIONS
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