Drug interactions are probably more common than veterinarians think !

Many clinical conditions require the administration of more than one drug simultaneously and, in general, interactions are rarely recognized or reported. However, clinicians should be diligent and need to keep up to date with developments in this area. It is particularly important to know  if an interaction is listed on the data sheet of a drug that is to be used concurrently with another.

Diuretics are widely used in the management a myriad of conditions from heart failure to head injuries. They are frequently used in combination with other drugs and particular care is needed if they are used with the following drugs, as interactions are reported on data sheets :

• Digoxin and other cardiac glycosides - furosemide and spironolactone increase the effect of digoxin, and digoxin may become toxic if hypokalaemia occurs. Monitor plasma potassium and give supplements if necessary
• Aminoglycosides (eg amikacin, apramycin, dihydrostreptomycin,  framycetin, gentamicin, kanamycin, neomycin, paromomycin, streptomycin, tobramycin) - may show  increased ototoxicity with furosemide
• Cephalosporins - increase nephrotoxicity may occur when used with furosemide 
• Sulphonamides - allergic reactions to sulphonamides (or potentiated sulphonamides) may occur when they are used with diuretics

Other drugs in common use and with which a potential interaction may occur with diuretics are :

• ACE inhibitors - increased risk of developing hyperkalaemia when given with potassium-sparing diuretics (Spironolactone, amiloride)
• Corticosteroids - in the presence of furosemide or thiazide diuretics there is an increased risk of developing hyperkalaemia, and the efficacy of the diuretic may be reduced.
• Non-steroidal anti-inflammatory drugs (NSAIDs) - may reduce the diuretic efficacy of spironolactone or amiloride and increase the risk of hyperkalaemia developing.
• Propranolol, atenolol  - if hypokalaemia develops there is an increased risk of ventricular arrhythmias with these drugs 

Other, less frequently prescribed drugs that interact with diuretics include : Acetazolamide, Aspirin,  Calcium salts, Chlorpropamide, Glipizide, Glibenclamide,  Lidocaine, Oestrogens, , Quinidine and Tolbutamide.

Feedback Request

If you have seen a case of a suspected drug interaction with diuretics Provet would like to hear from YOU. feedback@provet.co.uk