Drug information of Torsemide

Torsemide


Torsemide or torsemide is a pyridine-sulfonylurea type loop diuretic mainly used in the management of edema associated with congestive heart failure. It is also used at low doses for the management of hypertension.

Mechanism of effect

Torasemide inhibits the Na+/K+/2Cl--carrier system (via interference of the chloride binding site) in the lumen of the thick ascending portion of the loop of Henle, resulting in a decrease in reabsorption of sodium and chloride.

This results in an increase in the rate of delivery of tubular fluid and electrolytes to the distal sites of hydrogen and potassium ion secretion, while plasma volume contraction increases aldosterone production. The increased delivery and high aldosterone levels promote sodium reabsorption at the distal tubules, and By increasing the delivery of sodium to the distal renal tubule, torasemide indirectly increases potassium excretion via the sodium-potassium exchange mechanism.

torasemide increases the urinary excretion of sodium, chloride, and water, but it does not significantly alter glomerular filtration rate, renal plasma flow, or acid-base balance. Torasemide's effects as a antihypertensive are due to its diuretic actions. By reducing extracellular and plasma fluid volume, blood pressure is reduced temporarily, and cardiac output also decreases.

Pharmacodynamic

Torasemide or torsemide is a novel loop diuretic belonging to pyridine sulphonyl urea. It differs from other thiazide diuretics in that a double ring system is incorporated into its structure. Like thiazides, loop diuretics must be secreted into the tubular fluid by proximal tubule cells.

In the thick ascending loop Na+ and Cl- reabsorption is accomplished by a Na+/K+/2Cl- symporter. The thick ascending limb has a high reabsorptive capacity and is responsible for reabsorbing 25% of the filtered load of Na+. The loop diuretics act by blocking this symporter. Because of the large absorptive capacity and the amount of Na+ delivered to the ascending limb, loop diuretics have a profound diuretic action.

 In addition, more distal nephron segments do not have the reabsorptive capacity to compensate for this increased load. The osmotic gradient for water reabsorption is also reduced resulting in an increase in the amount of water excreted.

Pharmacokinetics

Absorption

Bioavailability: 80%

Onset: PO, 1 hr

Duration: PO, 6-8 hr; IV, 6 hr

Peak plasma time: PO, 1 hr

Peak effect: Diuresis, 1-2 hr; antihypertensive effect, 4-6 weeks

Distribution

Protein bound: 99%

Vd: 12-15 L (doubled in cirrhosis)

Metabolism

Metabolized in liver by CYP450 system

Metabolites: M1 (active), M3 (active), M5 (inactive)

Elimination

Half-life: 3.5 hr

Renal clearance: 0.38-0.78 L/hr

Excretion: Urine (20%)

Dosage

Usual Adult Dose for Edema

Edema Associated with Congestive Heart Failure:
IV and oral: 10 to 20 mg once a day
Edema Associated with Renal Disease:
IV and oral: 20 mg once a day

Edema Associated with Hepatic Disease:
IV and oral: 5 to 10 mg once a day together with an aldosterone antagonist or a potassium-sparing diuretic

Usual Adult Dose for Hypertension

5 mg orally once a day; if diuresis remains inadequate after 4 to 6 weeks, titrate up to 10 mg orally once a day; if diuresis remains inadequate with 10 mg, an additional antihypertensive should be added.

Drug contraindications

Anuria , hypersensitivity to this drug

Alerts

Use with caution in diabetes mellitus, fluid or electrolyte imbalance (hypokalemia, hyponatremia), hyperglycemia, hyperlipidemia, hyperuricemia or gout, severe liver disease with cirrhosis and ascites

Use with caution in cirrhosis; avoid changes in fluid and electrolyte balance and acid-base status, which may lead to hepatic encephalopathy

Monitor fluid status and renal function to prevent azotemia, oliguria, and reversible increases in blood urea nitrogen (BUN) and creatinine

Excessive diuresis may cause potentially symptomatic dehydration, blood volume reduction and hypotension and worsening renal function, including acute renal failure particularly in salt-depleted patients or those taking renin-angiotensin aldosterone inhibitors; worsening of renal function can also occur with concomitant use of nephrotoxic drugs (e.g., aminoglycosides, cisplatin, and NSAIDs); monitor volume status and renal function periodically

Points of recommendation

  • Avoid driving and doing other tasks or actions that call for you to be alert until you see how this medicine (torsemide tablets) affects you.
  • To lower the chance of feeling dizzy or passing out, rise slowly if you have been sitting or lying down. Be careful going up and down stairs.
  • If you have high blood sugar (diabetes), you will need to watch your blood sugar closely.
  • Have your blood pressure checked often. Talk with your doctor.
  • Have blood work checked as you have been told by the doctor. Talk with the doctor.
  • If you are on a low-salt or salt-free diet, talk with your doctor.
  • You may need extra potassium. Talk with your doctor.
  • If you are taking this medicine and have high blood pressure, talk with your doctor before using OTC products that may raise blood pressure. These include cough or cold drugs, diet pills, stimulants, ibuprofen or like products, and some natural products or aids.
  • This medicine is a strong fluid-lowering drug (diuretic). Sometimes too much water and major elements (potassium) in the blood may be lost. This can lead to serious health problems. Your doctor will follow you closely to change the dose to match your body's needs.
  • Tell your doctor if you have too much sweat, fluid loss, throwing up, or loose stools. This may lead to low blood pressure.
  • Talk with your doctor before you drink alcohol.
  • Watch for gout attacks.
  • If you are taking lithium, talk with your doctor. You may need to have your blood work checked more closely while you are taking it with this medicine (torsemide tablets).
  • Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using this medicine while you are pregnant.
  • Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.

Pregnancy level

B


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