Transcript Document

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
_________________
 _________________
 _________________
 _________________
 _________________
 _________________
 _________________

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

 (not always related to a disorder, may be a normal side
effect of medication, see Table 28-1, p.585)
Urinary System DRUG therapy

See Chart @ top of page-584 in Textbook
◦
◦
◦
◦
◦
◦
Diuretics
Anti-infective
Urinary Tract Antiseptics
Urinary Tract Antispasmodics
Medications for overactive bladder
Medications for enuresis
DIURETICS
Increases diuresis (loss of water in the
body)
 Used with cardiovascular meds to
decrease load on the heart and decease
BP
 Decreases edema
 Also causes loss of sodium, potassium and
chlorides (next slide)
 Categorized by site of action:

◦ Thiazides
◦ Loop diuretics
◦ Osmotics
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)


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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 (______________) - symptoms
include> *lower-back/flank pain *fever
*headache *nausea/vomiting
Lower UTI (______________) - 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!
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Dietary factors – certain foods (see Box 28-1
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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

p587)
UTI - Drug Therapy

Antibacterials (sulfa-drugs, trimethoprim)
kills bacteria in the urine and systemically

Antiseptics (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 Education

Sulfonamides (sulfa-drugs) – take on emptystomach with a full glass of water – DRUGS OF
CHOICE FOR TX OF UTI

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 !!!
UTI – RX Patient Education (Cont.)
 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 !
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FEVER after starting the drugs may be a sign of a drugreaction, not a UTI-symptom
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Small, spastic-like bladder (‘tiny-tank’) that
empties automatically when filled to a certain
point
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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
(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

Always check UNIT’s (numerator/denominator)
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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
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“DA or A” = dose-available, what is ‘on-hand’
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“DO or O” = dose-ordered, what you ‘want’

“DF or V” = dosage-form or vehicle, of the ‘onhand’

“DG or X” = dose-to-give, this is the unknownamount of the on-hand drug that we are
calculating … this is the ‘X’ that we are solving
for.
Ratio and Proportion
can be written with : or /
Units of measurement must match …
numerator : denominator
or
numerator / denominator
 Ratio examples:
60-minutes : 1-hour
or
60-minutes / 1-hour
 Proportion examples:
60min : 1hr = 120min : 2hr or
60min / 1hr = 120min / 2hr
Let’s try one!: how many minutes in 2.5 hours ?

Ratio and Proportion
How many minutes in 2.5 hours ?
1.
2.
3.
4.
we are looking for x min / 2.5 hours
we know that 60 min / 1 hour
so set-up the problem as
60min / 1 hr = X min / 2.5hr
now multiply (means x extremes or cross-multiply)
X x 1 = 2.5 x 60
X = 150 minutes
5.
6.
150 minutes … our final answer
To check your answer: replace x with your answer in the original set
up and multiply. If both sides of the equation match, you are correct
60min / 1 hr = 150 min / 2.5hr
150 min x 1 = 60 x 2.5
150
=
150
Your Turn:
How many teaspoons in 5 tablespoons?
3 tsp : 1 tbsp
3 tsp : 1 tbsp = X tsp : 5 tbsp
3 x 5 = 1 x X
15 = X
Check answer:
3 x 5 = 15 x 1
15 = 15
Formula Method
O /A xV = X
“DA or A” = dose-available, what is ‘on-hand’
 “DO or O” = dose-ordered, what you ‘want’
 “DF or V” = dosage-form (vehicle), of the
‘on-hand’
 “DG or X” = dose-given, this is the unknownamount of the on-hand drug that we
are calculating
 Always check that the strengths of the
drug-ordered (O) and the drug-available
(A) 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 (O)?
--what strength is available (A)?
--what is the unit of measure (V)?
--how much do we need to give (X)?
Let’s Do an Example
Physician Ordered: warfarin 20 mg po daily
On hand:
warfarin 5 mg tabs
How many tabs will you give daily?
O/A x V = x
20 mg / 5 mg x 1 tab = x
4
x 1 tab = x
4 tabs = x
Try one in liquid form….
Dr Smith orders 2 mg of Valium IV to a patient with seizure
activity.You have a 5 mL vial that contains 10 mgs of Valium.
(10mg/5mL). How many mLs are you going to draw up?
Formula Method:
2 mg / 10 mg x 5 mL = X
0.2 x 5 mL
=X
1 mL
=X
Ratio/Proportion Method
10 mg : 5 mL = 2 mg : X mL
10 x X
= 5 x 2
10 X
= 10
X
=
1 mL
Check Answer:
2 mg / 10 mg x 5 mL = 1 mL
10 mg : 5 mL = 2 mg : 1 mL
0.2
10 x 1
x
5 mL
= 1 mL
1 mL = 1 mL
=
5
10 = 10
x 2
Dimensional Analysis




Does not require conversion between
measurement systems first
X always goes on the left side of the =
the ‘factors’ go on the right side of the =
◦ the first factor is always what was ordered
write the factors so that all “units” can be
cancelled except for the one you want your
answer to have
X = ordered
1
x available x conversion factor (if needed)
Example using DA:
Dr Smith orders 2 mg of Valium IV to a patient with seizure
activity. You have a 5 mL vial that contains 10 mgs of Valium.
(10mg/5mL). How many mLs are you going to draw up?
X = 2 mg
1
X = 2
5 mL
10 mg
x 5 mL
10
X = 10 mL
10
X =
x
1 mL
1 More Dimensional Analysis
(with a conversion)
Dr Jones ordered Levaquin 1g po q 12 h; you
have 500 mg tabs. How many tabs will you
give daily?
X=1g
1
x
1 tab
500 mg
X = 1 x 1 tab x 1000
500 x 1
X=
X=
1000
500
2 tabs
x 1000 mg
1g
Converting Grains (gr) to Milligrams (mg)
Grains is written totally different than other measurements:
the amount is written AFTER the unit and written in
Roman Numerals not standard numbers
Examples:
gr i = 1 grain
gr ii = 2 grains
gr v = 5 grains
gr ss = ½ grain (or 0.5 grain)
gr ¼ = ¼ grain (or 0.25 grain)
To convert grains to milligrams use the conversion of
1 gr = 60 mg
Convert the following gr to mg
gr v = _________ mg
gr ss = _________ mg
gr ¼ = _________ mg
gr iss = ________ mg
Answers:
gr v = 300 mg
(1 gr : 60 mg = 5 gr : X mg)
1 x X = 60 x 5
X = 300
gr ss = 30 mg
(1 gr : 60 mg = 0.5 gr : X mg)
1 x X = 60 x 0.5
X = 30
gr ¼ = 15 mg
(1 gr : 60 mg = 0.25 gr : X mg)
1 x X = 60 x 0.25
X = 15
gr iss = 90 mg
(i=1 and ss=0.5)
(1 gr : 60 mg = 1.5 gr : X mg)
1 x X = 60 x 1.5
X = 90
QUESTIONS
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