Drug Interactions of Antihypertensives (Part 7):

Drug Interactions of Loop Diuretics:

More presentations from Naina Mohamed Pakkir Maideen

©   Loop diuretics are useful to treat hypertension and edema associated with congestive heart failure or renal insufficiency. In patients with impaired kidney function, loop diuretics are more effective than thiazide diuretics.

©   Loop diuretics include Furosemide (Frusemide), Bumetanide, Torsemide and Ethacrynic acid.

©   Loop diuretics compete for the Cl⁻ binding site of Na⁺-K⁺-2Cl⁻ symporter (cotransporter) of thick ascending limb of the loop of Henle and inhibit the reabsorption of sodium (Na⁺), chloride (Cl⁻)and potassium (K⁺).   Loop diuretics prevent the generation of a hypertonic renal medulla by disrupting the reabsorption of these ions leading to increased urine production. Loop diuretics induce vasodilation and increased blood supply to the kidney by increasing the production of prostaglandins. 

©   Loop Diuretics can interact majorly with drugs such as Digoxin, Digitoxin, Sotalol, Dofetilide, Droperidol, Metolazone, Foscarnet, Arsenic Trioxide, Ketanserin, Bepridil, Cisplatin, Aminoglycoside Antibiotics and some Antivirals.

©   Moderate interaction of Loop Diuretics includes ACE Inhibitors, NSAIDs, Antidiabetics and Ginseng.

©   Frequent monitoring of potassium and magnesium is recommended when Loop Diuretics and Digitalis glycosides (Digoxin, Digitoxin) are used together.

©   Concomitant use of Loop diuretics and Sotalol, Dofetilide, Droperidol, Arsenic Trioxide, Ketanserin or Bepridil warrants the monitoring of the patients for the signs of Cardiotoxicity (Prolonged QTc interval, faintness, dizziness, and tachycardia).

©    Monitor for additive ototoxicity or nephrotoxicity, if concurrent therapy of Loop Diuretics and Aminoglycoside Antibiotics (Tobramycin, Streptomycin, Gentamicin, Kanamycin, Amikacin, Neomycin, Netilmicin) or Cisplatin is required.

©   The status of fluids and electrolytes should be closely monitored, when Loop diuretics and Metolazone are administered together.

©   Foscarnet elimination is impaired by Loop diuretics and to avoid the Foscarnet toxicity, a Thiazide diuretic is indicated.

©   Antivirals like Ritonavir, Ombitasvir and Dasabuvir may increase the risk of adverse events of Frusemide.

©   Monitor for hypotension, fluid status, and body weight regularly for up to two weeks after the initiation of ACE Inhibitors (Captopril, Lisinopril, Perindopril, etc) in patients taking Loop diuretics.

©   The patients taking both Loop diuretics and NSAIDs (Ibuprofe, Diclofenac, Naproxen, etc) should be monitored for diuretic efficacy and for signs of renal failure.

©    Concomitant use of a diuretic and an Antidiabetic agent warrants the monitoring of glucose levels more frequently.

©   Patients should be advised to discontinue use of Ginseng while taking loop diuretics, to avoid diuretic resistance. 

©   The patients with hypertension should bring a list of all of the drugs they are taking including prescription drugs, over-the-counter drugs, and any supplements, herbal or otherwise, during their visit to the doctor or pharmacist.