Metabolic Alkalosis Treatment & Management

The management of metabolic alkalosis depends primarily on the underlying etiology and on the patient’s volume status. In the case of vomiting, administer antiemetics, if possible. If continuous gastric suction is necessary, gastric acid secretion can be reduced with H2-blockers or more efficiently with proton pump inhibitors. In patients who are on thiazide or loop diuretics, the dose can be reduced or the drug can be stopped if appropriate. Alternatively, a potassium-sparing diuretic or acetazolamide can be added.

Acetazolamide also appears safe and effective in patients with metabolic alkalosis following treatment of respiratory acidosis from exacerbations of chronic obstructive pulmonary disease (COPD). ^{[16, 17]} One randomized trial found that the duration of mechanical ventilation in patients with COPD or obesity-hypoventilation syndrome with metabolic alkalosis was not significantly reduced in patients who received early administration of acetazolamide, compared with placebo. ^[18]  

However, a systematic review and meta-analysis of that trial and five other randomized controlled studies concluded that in patients with respiratory failure and metabolic alkalosis, therapy with acetazolamide or other carbonic anhydrase inhibitors may have favorable effects on blood gas parameters. In mechanically ventilated patients, carbonic anhydrase inhibitor therapy may decrease the duration of mechanical ventilation. ^[19]

For a discussion of metabolic alkalosis in children, see Pediatric Metabolic Alkalosis. For a general review of acid-base regulation, see Metabolic Acidosis.

If chloride-responsive alkalosis occurs with volume depletion, treat the alkalosis with an intravenous infusion of isotonic sodium chloride solution. Because this type of alkalosis is usually associated with hypokalemia, also use potassium chloride to correct the hypokalemia.

If chloride-responsive alkalosis occurs in the setting of edematous states (eg, congestive heart failure [CHF]), use potassium chloride instead of sodium chloride to correct the alkalosis and avoid volume overload. If diuresis is needed, a carbonic anhydrase inhibitor (eg, acetazolamide) or a potassium-sparing diuretic (eg, spironolactone, amiloride, triamterene) can be used to correct the alkalosis.

Management of chloride-resistant metabolic alkalosis is based on the specific cause.

Primary hyperaldosteronism

Metabolic alkalosis is corrected with the aldosterone antagonist spironolactone or with other potassium-sparing diuretics (eg, amiloride, triamterene). If the cause of primary hyperaldosteronism is an adrenal adenoma or carcinoma, surgical removal of the tumor should correct the alkalosis. In glucocorticoid-remediable hyperaldosteronism, metabolic alkalosis and hypertension are responsive to dexamethasone.

Cushing syndrome

Potassium-sparing diuretics should correct the alkalosis until surgical therapy is performed. Definitive therapy includes transsphenoidal microresection of adrenocorticotropic hormone (ACTH)–producing pituitary adenomas and adrenalectomy for adrenal tumors.

Syndrome of apparent mineralocorticoid excess

Metabolic alkalosis in the syndrome of AME may be treated with potassium-sparing diuretics. On the other hand, dexamethasone may be used to suppress cortisol production by inhibiting ACTH. Unlike cortisol and some synthetic glucocorticoids, dexamethasone does not activate the mineralocorticoid receptor.

Licorice ingestion

Discontinuation of licorice ingestion corrects the alkalosis; however, because full recovery of the enzyme 11B-HSD may take as long as 2 weeks following long-term licorice use, potassium-sparing diuretics can be used during this interval.

Bartter syndrome and Gitelman syndrome

Metabolic alkalosis can be corrected partially with the following:

• Potassium supplementation
• Potassium-sparing diuretics
• Nonsteroidal anti-inflammatory drugs
• ACE inhibitors

Indomethacin is the most prescribed NSAID for the treatment of Bartter syndrome; in patients with Gitelman synrome it has shown to be more effective than eplerenone or amiloride for treating associated hypokalemia. ^[20]

Liddle syndrome

Metabolic alkalosis can be treated with amiloride or triamterene but not with spironolactone. Both amiloride and triamterene inhibit the apical sodium ion channel in the collecting duct. Spironolactone, which is a mineralocorticoid receptor antagonist that works upstream of the defective sodium ion channel, does not correct the alkalosis or the hypertension.

Hydrochloric acid

Intravenous HCl is indicated in severe metabolic alkalosis (pH >7.55) or when sodium or potassium chloride cannot be administered because of volume overload or advanced renal failure. HCl may also be indicated if rapid correction of severe metabolic alkalosis is warranted (eg, cardiac arrhythmias, hepatic encephalopathy, digoxin cardiotoxicity). ^[21] Seek the advice of a nephrologist when severe alkalosis is present and HCl therapy or dialysis is contemplated.

Dialysis

Both peritoneal dialysis and hemodialysis can be used with certain modifications of the dialysate to correct metabolic alkalosis. The main indication of dialysis in metabolic alkalosis is in patients with advanced renal failure, who usually have volume overload and are resistant to acetazolamide.

With hemodialysis, metabolic alkalosis may be corrected by using a low-bicarbonate dialysate (bicarbonate can be as low as 18 mmol/L). Otherwise, acetate-free biofiltration (buffer-free dialysate), in which bicarbonate is not present in the dialysate but is infused separately as needed, may be used. In peritoneal dialysis, dialysis can be performed using isotonic sodium chloride solution as the dialysate.

Seek the advice of a nephrologist when severe alkalosis is present and HCl therapy or dialysis is contemplated.