Week 8 seminarWeek 8 seminar

Urinary System Disorders

and

Calculating ‘Desired-Doses’

(chapter-28 and chapter-9)

The Urinary SystemThe 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 Common symptoms of of Urinary System DisordersUrinary System DisordersAnorexia, Nausea, VomitingFatigue, Lethargy, MalaiseDysuria, urgency, frequency,

hematuriaPain in lower-back (kidney area),

flank (sides)Fever, disorientation

Common Side-effects of Rx’s Common Side-effects of Rx’s for Urinary System Disordersfor Urinary System Disorders

Drying of secretionsDrowsiness, dizziness, sedationRash, hives, ‘urticaria’GI effects (nausea, vomiting, diarrhea)HeadacheDiscoloration 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 Urinary System DRUG therapytherapySee Chart @ top of page-584 in

Textbook

◦Diuretics ◦Anti-infective◦Urinary Tract Antiseptics◦Urinary Tract Antispasmodics◦Medications for overactive bladder◦Medications for enuresis

DIURETICSDIURETICSIncreases 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 Electrolyte Imbalance EffectsEffectsElectrolyte level symptoms

SODIUM high Edema, thirst, high temp, flushing

low Stomach-cramps, vomiting, diarrhea

POTASSIUM high Abdominal-distension, diarrhea

low Paralysis, weakness, muscle function

CALCIUM high Anorexia, nausea, coma, weakness

low Muscle-cramp/twitching, numbness/tingling of fingers, toes, lips

MAGNESIUM high Flushing, sweating, low temp, cardiac depression

low Abnormal heart rhythms, neurotoxicity

Urinary Tract Infections Urinary Tract Infections (UTI)(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’sUpper 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 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

UTIUTI - Drug Therapy - Drug TherapyAntibacterials (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

UTIUTI – RX Patient – RX Patient EducationEducation

Sulfonamides (sulfa-drugs) – take on empty-stomach 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 !!!

UTIUTI – RX Patient Education – RX Patient Education ((Cont.)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 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 forTime for

Calculating Doses Calculating Doses (nonparenteral) (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 Why go with ONE method ?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 Basic Rules for Confident CalculatingCalculating

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 9-1Box 9-1(p.166) (p.166) Dosage-Dosage-formsformsKnow which types of dosage-forms

can be divided, halved, altered Scored tablets – okay to breakOral – 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 labeling” the parts of the problemproblem

“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 ‘on-hand’

“DG or X” = dose-to-give, 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 Ratio and Proportion can be written with : or /can be written with : or /

Units of measurement must match … numerator : denominator or

numerator / denominatorRatio examples:

60-minutes : 1-hour or

60-minutes / 1-hourProportion examples:

60min : 1hr = 120min : 2hr or

60min / 1hr = 120min / 2hrLet’s try one!: how many minutes in 2.5

hours ?

Ratio and ProportionRatio and Proportion

How many minutes in 2.5 hours ?1. we are looking for x min / 2.5 hours 2. we know that 60 min / 1 hour 3. so set-up the problem as

60min / 1 hr = X min / 2.5hr 4. now multiply (means x extremes or cross-multiply)

X x 1 = 2.5 x 60 X = 150 minutes

5.150 minutes … our final answer 6. 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:Your Turn:

How many teaspoons in 5 tablespoons?

3 tsp : 1 tbsp3 tsp : 1 tbsp = X tsp : 5 tbsp3 x 5 = 1 x X 15 = X

Check answer: 3 x 5 = 15 x 1 15 = 15

Formula MethodFormula MethodO / A x V = XO / A x V = 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 unknown-

amount 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 MethodFormula Method cont. 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 ExampleLet’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 = x20 mg / 5 mg x 1 tab = x 4 x 1 tab = x

4 tabs = x

Try one in liquid form….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: Ratio/Proportion Method2 mg / 10 mg x 5 mL = X 10 mg : 5 mL = 2 mg : X

mL0.2 x 5 mL = X 10 x X = 5 x

2 1 mL = X 10 X = 10

X = 1 mLCheck Answer:2 mg / 10 mg x 5 mL = 1 mL 10 mg : 5 mL = 2 mg : 1 mL0.2 x 5 mL = 1 mL 10 x 1 = 5 x 2 1 mL = 1 mL 10 = 10

Dimensional AnalysisDimensional AnalysisDoes not require conversion between

measurement systems firstX 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 x available x conversion factor (if needed)

1

Example using DA: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 x 5 mL 1 10 mg

X = 2 x 5 mL 10

X = 10 mL 10

X = 1 mL

1 More Dimensional Analysis 1 More Dimensional Analysis (with a conversion)(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 = 1 g x 1 tab x 1000 mg 1 500 mg 1 g

X = 1 x 1 tab x 1000 500 x 1

X = 1000 500X = 2 tabs

Converting Grains (gr) to Milligrams Converting Grains (gr) to Milligrams (mg)(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 Convert the following gr to mgmg

gr v = _________ mg

gr ss = _________ mg

gr ¼ = _________ mg

gr iss = ________ mg

Answers: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 (1 gr : 60 mg = 1.5 gr : X mg)

(i=1 and ss=0.5) 1 x X = 60 x 1.5 X = 90

QUESTIONSQUESTIONS

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