Furosemide Flashcards
What is furosemide
Loop diuretic used to treat hypertension and edema in congestive heart failure, liver cirrhosis/failure, renal disease/failure.
It acts on the kidneys to increase water loss from the body.
How does it work?
Inhibits electrolyte reabsorption from the kidneys and enhanc the excretion of water from the body.
It has a fast onset and short duration
Indications
Edema associated with heart failure - Can result in fluid accumulation in the body leading to edema. Furosemide reduces fluid overload and relieving symptoms of swelling and shortness of breath.
Hypertension - By promoting diuresis, it helps to reduce blood volume and in turn lowers BP. Furosemide is not considered first line treatment.
Renal impairment - Furosemide will enhance diuresis and prevent fluid overload, by increasing urine output, it can help remove waste and toxin and improve kidney function.
Liver cirrhosis - condition characterized by irreversible scarring of liver tissue, this can lead to fluid accumulation in the abdomen (ascites). Furosemide will promote diuresis and reduce abdominal swelling.
Pulmonary edema - Is the accumulation of fluid in the lungs, often caused by congestive heart failure or acute respiratory distress syndrome. Helps eliminate excess fluid from the lungs and improve breathing.
Pharmacodynamics (What does the drug to the body)
Potent loop diuretic that works to increase the excretion of sodium and water by the kidneys, by inhibiting their reabsorption from the proximal and distal tubules, as well as the loop of Henle.
Increases the urine output by the kidney.
Mechanism of Action (how it produces its effect)
Targets specific transport protein called Na-K-2CI cotransporter, which is responsible for the reabsorption of sodium, chloride and potassium ions.
Promotes diuresis by blocking tubular reabsorption of sodium and chloride. This inhibition results in the increased excretion of water along with sodium, chloride, magnesium, calcium, hydrogen and potassium ions. This may require supplements to maintain normal levels and prevent imbalances.
It decreases the excretion of uric acid.
Where does furosemide metabolise?
Kidneys and liver, to a smaller extent. The kidneys are responsible for about 85% of total furosemide clearance.
Route of elimination
Kidneys are responsible for 85% of total furosemide clearance, where 43% undergoes renal excretion. 50% of furosemide is excreted unchanged in urine.
Half-life (The time it takes for a drug to reduce by half in the body)
4 hours following oral
4.5 hours following IV
2 hours parenteral
24 hours in patients with severe renal failure.
Clinical consequence from overdose
Depends on the extent of electrolyte and fluid loss.
Dehydration
Blood volume reduction
Hypotension
Electrolyte imbalance
Hypokalemia
Hypochloremic alkalosis
Hemoconcentration
cardiac arrhythmias
Symptoms of overdose
Acute renal failure
Thrombosis
Delirum
Flaccid paralysis
Apathy
Confusion
Precipitate hepatic coma
Weak pulse
Extreme thirst
Mood changes
Food interactions
Alcohol increases risk of orthostatic hypotension
Natural licorice can lead to hypokalemia
Increase potassium-rich food consumption
Common side effects
Diarrhea, constipation, loss of appetite
Numbness or tingling
Headache, dizziness
Blurred vision
Low blood pressure
Electrolyte imbalances (muscle cramps, weakness, irregular heartbeat and fatigue.
Increased urination - expected.
Serious side effects
Allergic reaction (hives, difficulty breathing, swelling)
Severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering or peeling)
Light headedness, like feeling the need to pass out
Ringing in the ears (tinnitis), hearing loss
Muscle spasms or contractions
Pale skin, easy bruising, unusual bleeding
High blood sugar (increased thirst, increased urination, dry mouth, fruity breath.
Kidney problems (swelling, urinating less, feeling tired or short of breath
Signs of liver or pancreas issues (loss of appetite, upper stomach pain (may spread to the back), nausea or vomiting, dark urine, jaundice (yellowing of the skin or eyes)
Signs of electrolyte imbalance (increased thirst or urination, constipation, muscle weakness, leg cramps, numbness or tingling, feeling jittery, fluttering in the chest)
Common conditions after using furosemide
Hyponatremia
Hypochloremia
Hypokalemia
Blood cholesterol increase
Blood uric acid increase
Gout
Hemoconcentration
Urine volume increase
Contraindications
Anuria - inability to produce urine. furosemide relies on urine production to exert its diuretic effects.
Severe electrolyte imbalance - Furosemide may worsen imbalances.
Hypovolemia - This is a decrease in blood volume. Furosemide promotes diuresis which reduces blood volume and can worsen the condition.
Hepatic coma.
Allergy to sulfonamide medication - furosemide belongs to sulfonamide class.
Inform doctor about kidney disease, enlarged prostate, urination problems, cirrhosis or other liver disease, electrolyte imbalance, high cholesterol, gout, lupus, diabetes or an allergy to sulfa drugs, MRI or any scan using radioactive dye injected into veins (contrast dyes can harm the kidneys)
