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
_________________
_________________
_________________
_________________
_________________
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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)
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!
Dietary factors – certain foods (see Box 28-1
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 !
FEVER after starting the drugs may be a sign of a drugreaction, 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
(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)
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 or A” = dose-available, what is ‘on-hand’
“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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