Torsemide

Torasemide is a p.o. and i.v. loop diuretic with a sulfonamide group in the molecule.

Loop diuretics are inhibitors of the Na+/K+/2Cl- - symporter in the thick ascending limb of the loop of Henle of the nephron. As a result, the reabsorption of sodium, potassium, and chloride is inhibited, so that these, along with water, are increasingly excreted in the urine. Toresamide thus has a diuretic and thus antihypertensive and anti-edematous effect.

Torasemide is a potent agent in the acute therapy of any type of edema due to its rapid and potent action (Fallahzadeh MA et al. 2017). It is important to note that already in intravenous monotherapy, but especially in the combination of loop diuretics with other diuretics, there is a risk of hypokalemia with life-threatening arrhythmias. In this respect, strict monitoring of electrolytes is necessary.

Loop diuretics selectively inhibit NaCl reabsorption in the thick ascending branch of the loop of Henle by inhibiting the Na+/K+/2Cl- symporter (co-transporter). Because of the high absorption capacity in this segment, loop diuretics are the most efficient diuretic agents (Buggey J et al (2015). Loop diuretics have an approximately linear dose-response relationship over a wide dose range. This means that a stronger diuresis can be achieved with an increase in dose (ceiling effect).

Heart failure NYHA I-IV if water retention is clinically present (according to ESC guidelines 2012 increase up to 100 mg/day possible).

Hepatic and renal oedema: torasemide is preferred here, often in combination with thiazides.

Arterial hypertension (2nd choice agent).

To note:

• Do not administer in the evening
• Exsiccosis especially in geriatric patients
• In case of cardiac decompensation: consider switching to furosemide

Torasemide 5 mg p.o. 1-0-0; increase dose up to 20 mg 1-0-0 taking renal function into account.

Dose adjustments:

• Renal impairment
• Torasemide 100 mg/day should be used only from GFR <30 mL/min
• Consider necessary dose increase on the one hand and worsening of renal function at too high doses on the other hand.
• Hepatic insufficiency: contraindication in case of severe hepatic dysfunction

Common:

• Loss of appetite
• Fatigue
• Weakness
• Electrolytes: increase of metabolic alkalosis
• Disturbances of water and electrolyte balance (depending on dosage)
• CNS: headache, vertigo
• Gastrointestinal: stomach pain, nausea, vomiting, diarrhea, constipation

Other:

• Muscle spasms
• Increased concentrations of uric acid, glucose, triglycerides, cholesterol, liver enzymes (gamma-GT) in blood.

Occasional:

• Paresthesia
• Dry mouth
• urinary retention and overdistension of the bladder in patients with micturition disorders
• Increased concentrations of creatinine and urea in the blood.Very rarely:
• Thrombocytopenia
• Erythropenia
• leukopenia
• Visual disturbances
• Tinnitus
• hearing loss
• thromboembolic complications
• confusional states
• hypotension
• cardiac and central circulatory disorders (arrhythmias, angina, myocardial infarction, syncope)
• Pancreatitis

skin:

• Vasculitides (Palop-Larrea V et al. 1998)
• Pruritus
• Hypereosinophilia syndrome
• Photosensitivity: porphyria cutanea tarda-like clinical pictures (Pérez-Bustillo A et al. 2008), as well as lichenoid exanthema on sun-exposed skin areas (Byrd DR et al. 1997) are described.
• Serious skin reactions are rare (see furosemide below).

In case of prolonged therapy, laboratory values should be monitored regularly.

Hypersensitivity to the active substance or to one of the excipients.

electrolyte imbalances: hypokalemia, hyponatremia, hypocalcemia

Hypovolemia and (impending) acute renal failure.

Significant micturition disorders

1. Buggey J et al (2015) A reappraisal of loop diuretic choice in heart failure patients. In: American Heart Journal 169: 323-333
2. Byrd DR et al (1997) Photosensitive lichenoid reaction to torsemide--a loop diuretic. Mayo Clin Proc 72:930-931.
3. Martin N et al (2004) Idiopathic hypereosinophilia with cardiac involvement. Dtsch Med Wochenschr 129:557-560.
4. Mentz RJ et al (2016) Torsemide Versus Furosemide in Patients With Acute Heart Failure (from the ASCEND-HF Trial). The American journal of cardiology 117404-411
5. Palop-Larrea V et al (1998) Vasculitis with acute kidney failure and torasemide. Lancet 352:1909-1910.
6. Pérez-Bustillo A et al (2008) Torsemide-induced pseudoporphyria. Arch Dermatol 144:812-813.
7. Roush GC et al (2014) Diuretics: a review and update. Journal of cardiovascular pharmacology and therapeutics 19: 5-13.