Urinary system Flashcards
what is the main function of the urinary system?
to produce urine from the kidneys
the kidneys enable elimination of drugs/toxins, maintain normal blood pH, and preserve fluid and electrolyte balance
nephron
functional unit of the kidney, forms urine
glomerulus
cluster of capillaries, filters substances from blood into glomerular filtrate through glomerular filtration
tubules
responsible for reabsorption or secretion of substances
how do urinary drugs work?
some directly influence urine production and electrolyte balance
others maintain blood pressure and reduce urinary system disease
what do diuretics do?
promote diuresis: process of increasing the amount of urine excrete by the kidney and promote release of water from the tissues
helps to decrease edema and lower blood pressure
what is the drug name for loop diuretics?
Furosemide
what do loop diuretics do?
blocks reabsorption of electrolytes which increases diuresis
treats congestive heart failure, pulmonary edema, and hypertension
what are some adverse effects of loop diuretics?
heart arrhythmias and electrolyte imbalances
what is the drug name for potassium sparing diuretics?
Spironolactone
what do potassium sparing diuretics do?
reduces excretion of potassium while increasing excretion of water and sodium, treats congestive heart failure, usually used as a minor diuretic or with other drugs since it’s less effective than loop diuretics
what is the adverse effect of potassium sparing diuretics?
hyperkalemia
what is the drug name for thiazide diuretics?
hydrochlorothiazide
what do thiazides do?
blocks sodium reabsorption and promotes chloride excretion which increases diuresis, controls blood pressure, can be administered IM, IV, or oral to small animals, horses, and cattle
what are the drug names for carbonic anhydrase inhibitors?
acetazolamide, dichlorphenamide, methazolamide
what do carbonic anhydrase inhibitors do? (diuretic)
blocks the enzyme that reabsorbs bicarbonate in the proximal convoluted tubule, increases sodium, potassium, and bicarbonate excretion, and decreases intraocular pressure in glaucoma
what is the drug name of osmotic diuretics?
Mannitol
what do osmotic diuretics do?
promotes excretion of sodium, chloride, potassium, and water
prevents kidney failure, decreases intracranial pressure, and decreases intraocular pressure
what are the adverse effects of osmotic diuretics?
uncommon but can include fluid/ electrolyte imbalance and vomiting
what do antihypertensives do?
lowers blood pressure
what are animals with high blood pressure at risk for?
they’re at risk of developing cardiac and renal dysfunction
what are the drug names of angiotensin-converting enzyme inhibitors (ACE inhibitors)?
(antihypertensive)
Enalapril, Captopril, Lisinopril, and Benazepril
what do ACE inhibitors do?
decrease sodium retention and decrease levels of antidiuretic hormone which promotes diuresis and treats hypertension
treats congestive heart failure and chronic renal failure
what are the adverse effects of ACE inhibitors?
there are very few but can include vomiting, diarrhea, and anorexia
what are the drug names of Angiotensin receptor blockers (ARBs)? (antihypertensive)
Telmisartan and Losartan
what do ARBs do?
promote vasodilation, decrease potassium secretion, and increase sodium excretion
what are the adverse effects of ARBs?
vomiting, diarrhea, lethargy, dehydration, low appetite, and weight loss
what are the drug names of calcium channel blockers?
(antihypertensive)
Diltiazem (controls heart rate) and Amlodipine (controls blood pressure)
what do calcium channel blockers do?
blocks influx of calcium ions into myocardial and vascular cells which causes inhibition of cardiac and smooth muscle contractility which increases vasodilation
what are the adverse effects of calcium channel blockers?
hypotension, bradycardia, and edema
what do direct-acting arteriole vasodilators do?
(antihypertensive)
relax smooth muscles of the blood vessels
what drugs are direct-acting arteriole vasodilators?
(anithypertensive)
hydralazine: used as an emergency drug due to rapid blood pressure reduction, adverse effect: hypotension
beta-adrenergic antagonists (beta blockers)
what are the different types of beta blockers used as direct-acting arteriole vasodilators?
Propranolol and Carvedilol: nonselective beta blockers
Atenolol, Metoprolol, and Esmolol: beta 1 blockers that promote bradycardia and bronchoconstriction, treats cardiomyopathy
hyperphosphatemia
phosphorus accumulated in the blood due to kidneys not filtering it out
what does aluminum hydroxide do?
(phosphate binder)
binds to dietary phosphorus, decreases amount of phosphorus absorbed by intestines
what is the adverse effect of aluminum hydroxide?
(phosphate binder)
constipation
what do uroliths cause?
can cause hematuria, dysuria, and obstructions from becoming lodged in the urethra
what are some different treatment options for uroliths?
stones can be dissolved with antibiotics therapy, medical dissolution, prescription diet and/or surgical removal
how can uroliths be prevented after being treated?
increasing amount of water the animal drinks and feeding a diet that alters the pH of the urine
how do struvite crystals form?
they form in alkaline urine
how are struvite crystals treated in dogs?
associated with bacterial infections or urinary tract so treated with antibiotics and prescription diets that dissolve them by acidifying the urine
drug: Methionine
how are struvite crystals treated in cats?
can be present without infection, once dissolved/broken apart/removed a urine-acidifying diet with low concentration of struvite precursors should be fed
what animals should never be fed acidifying diets or drugs?
animals with renal disease
how do calcium oxalate uroliths form?
they form in concentrated urine
what breeds are calcium oxalate uroliths common in?
miniature schnauzers, yorkies, lhasa apsos, bichon frises, shih tzus, and miniature poodles
how are calcium oxalate uroliths treated?
can’t dissolve them so usually surgically removed, prevented by feeding a prescription diet that keeps urine pH at 6.5-7.5 or can be prescribed urinary alkalinizers
how do urate uroliths form?
made from purines which are found in high levels in meat, organs, and seafood, can be formed because of a genetic condition in Dalmatians and bulldogs or Aussies can develop them for no reason
how are urate uroliths treated?
can be dissolved and prevented with a prescription diet (that has low purine and urine-alkalinizing properties) and/or medicine (Allopurinal stops enzyme that converts purine into uric acid)
how do cystine crystals form?
can form in dogs that have a reabsorption defect that reduces reabsorption of amino acid by the kidneys, typically in young male dogs
how are cystine crystals treated?
treated/ controlled by prescription food or medication
diet: protein restricted, alkalinizing to raise pH to >7.5
meds: urinary alkalinizers or potassium citrate (CitraVet)
urinary incontinence
loss of voluntary control of micturition
what are the 2 categories of urinary incontinence?
neurologic disorders: spinal cord injuries, brain diseases, disruption of nerves controlling the bladder
non-neurologic disorders: urethral disorders due to decreased levels of sex hormone and/or stress or urge incontinence
how is neurologically caused incontinence treated?
with drugs that affect the nerves of the muscles of the urinary system
what do cholinergic agonists do?
treats incontinence caused by damage to the nerves that control the relaxation of the bladder
Bethanechol promotes voiding
adverse effects: vomiting and diarrhea
what do anticholinergics do?
treats incontinence by promoting urine retention and causes muscle relaxation
(neurologically caused incontinence)
Propantheline adverse effects: dry mouth, dry eyes, urinary retention, constipation (anti-SLUDDE)
what do adrenergic antagonists do?
alpha adrenergic antagonist drugs: phenoxybenzamine, prazosin, and tamsulosin
treats decreased urinary tone due to overdistention of the bladder
adverse effects: weakness due to decreased blood pressure
how is non-neurologically caused incontinence treated?
hormones may be used to treat spayed/neutered animals or drugs that increase urethral sphincter tone
Estriol
synthetic estrogen used to treat urine dribbling in spayed dogs
Estriol
synthetic estrogen used to treat urine dribbling in spayed dogs
adverse effects: decreased appetite, vomiting, mammary hyperplasia, swollen vulva, behavioral changes
Testosterone cypionate or testosterone propionate
synthetic testosterones used to treat urinary incontinence in males
adverse effects: development of prostate disorders and behavior changes
what do alpha and beta-adrenergic agonists do to treat non-neurologically caused incontinence?
increases the tone of urethral sphincters
Phenylpropanolamine adverse effects: anorexia, restlessness, hypertension
Pseudophedrine: controlled drug
what do skeletal muscle relaxants do?
treats animals with urge incontinence or urethral obstructions due to increased external urethral sphincter tone
Dantrolene, Diazepam, Baclofen
adverse effects: mild tranquilization and sedation
