carbonic anhydrase inhibitors
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Related to carbonic anhydrase inhibitors: acetazolamide
carbonic anhydrase inhibitorsA class of drug that act by blocking the action of the enzyme CARBONIC ANHYDRASE. This enzyme greatly speeds up the reaction between carbon dioxide and water to form carbonic acid, a compound needed for the production of many of the body's secretions. Carbonic anhydrase is present in high concentration in the eye, the kidneys, stomach lining and pancreas. Inhibitor drugs reduce the rate of secretion of aqueous humour in the eye and is useful in treating GLAUCOMA. These drugs are also valuable in treating mountain sickness, periodic paralysis and absence attacks (petit mal). The group includes ACETAZOLAMIDE and DORZOLAMIDE.
diureticspowerful drugs, often termed ‘water tablets’, that control hypertension and peripheral oedema; action of some local anaesthetics is antagonized by concomitant use of some diuretics (see Table 1), e.g. aldosterone antagonists (e.g. spironolactone); carbonic anhydrase inhibitors, e.g. acetazolamide; loop diuretics, e.g. furosemide; osmotic diuretics, e.g. mannitol; potassium-sparing diuretics, e.g. amiloride, or in combination with other diuretics; thiazide diuretics, e.g. bendroflumethiazide
|Local anaesthetic agent Proprietary name||Principal drug interactions||Effect of interaction|
|Increased myocardial depression|
Increased risk of ventricular arrhythmias if lidocaine is given with quinpristin/dalfopristin
Increased risk of ventricular arrhythmias if lidocaine is given with any drug that prolongs the QT interval of the cardiac cycle
Plasma concentration of lidocaine increased by amprenavir, atazanavir and lopinavir
Increased myocardial depression
Increased risk of lidocaine toxicity when given with propranolol
The action of lidocaine is antagonized by the hypokalaemia caused by acetazolamide, loop diuretics or thiazide and related diuretics (i.e. a greater dose of lidocaine would be required to achieve anaesthesia)
Increased risk of ventricular arrhythmia if lidocaine is given with dolasetron
Plasma concentration of lidocaine increased when given with cimetidine; risk of lidocaine toxicity increased with cimetidine
|Beta-blockers||Increased risk of bupivacaine toxicity when given with propranolol|
Increased risk of myocardial depression if given with other antiarrhythmic agents
|Increased risk of myocardial depression if given with antiarrhythmic agents|
Increased risk of methaemoglobinaemia if given with sulphonamide antibacterial agents
|Antidepressants||Metabolism of ropivacaine is inhibited by fluvoxamine, thereby enhancing the risk of ropivacaine toxicity|
|Drug not listed in the British National Formulary|
carbonic anhydrase inhibitors
Drugs which inhibit the carbonic anhydrase enzyme in the ciliary epithelium of the ciliary body. This enzyme is essential for the formation of aqueous humour; its reduction results in a decrease in intraocular pressure. Those in use are sulfonamide derivatives. They are administered systemically (e.g. acetazolamide) or topically in the treatment of glaucoma. Examples: acetazolamide, brinzolamide, dichlorphenamide, dorzolamide.