Alkali Therapy (Metabolic Acidosis / CKD-Related Acidosis) Pregnancy: Animal studies are insufficient with respect to effects on pregnancy, embryofoetal development, parturition and postnatal development, and the potential risk for humans is unknown — sodium bicarbonate should not be taken during pregnancy unless advised by a doctor. Breast-feeding: the effects of sodium administration during breast-feeding are not known and it should not be taken while breast-feeding unless advised by a doctor. The potential risks of sodium on fertility are not known.

Sodium Bicarbonate

Brand names: Various — tablets 500 mg, oral solution, IV infusion 1.26% / 4.2% / 8.4%

Oral sodium bicarbonate used in chronic kidney disease to correct the metabolic acidosis that accompanies declining renal function. This is the renal-replacement-of-base context rather than acute resuscitation use.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Metabolic acidosis: no fixed dose is stated in the SPC — the dosage is dependent upon the acid-base balance and electrolyte status of the patient and must be calculated on an individual basis.

Route: Oral — capsules to be swallowed whole with a drink of water

Frequency: Not stated for metabolic acidosis; determined by the individual calculation and by repeat acid-base/electrolyte monitoring

Source: UK SPC (eMC) for Sodium Bicarbonate 500 mg Capsules, §4.2 (https://www.medicines.org.uk/emc/product/101278/smpc). NO NUMERIC REGIMEN FOR ACIDOSIS EXISTS IN THIS SOURCE — the SPC deliberately individualises it; do not infer a mg or mmol/day figure from this draft, and source a CKD-specific guideline (with clinician sign-off) if the page needs a worked starting dose. SEPARATE INDICATION, NOT THE ACIDOSIS DOSE: for dyspepsia the SPC gives 1 g to 5 g when required — this is antacid dosing and must not be presented as the CKD acidosis regimen. TITRATION TARGET FROM §4.4: overtreatment with bicarbonate must be avoided and frequent monitoring of serum electrolytes and acid-base status is essential; in moderate and advanced chronic renal disease the association between serum bicarbonate concentration and all-cause mortality is U-shaped, with the lowest mortality at serum bicarbonate 26-29 mmol/L, the highest mortality below 22 mmol/L, and an increase in mortality also seen above 29 mmol/L. PAEDIATRIC: §4.2 states 'Not recommended'; §4.3 states it is not to be taken by children under 12 years old. §4.8 was fetched in full; §4.4/§4.5 were truncated at the source-fetch limit. The openFDA fallback in this bundle is an unrelated product (Elliotts B Solution, an intrathecal diluent for methotrexate/cytarabine) and was NOT used for any field.

Dose adjustments

Renal

§4.4: sodium bicarbonate should be given extremely cautiously to patients with renal impairment, heart failure, oedema, hypertension, eclampsia, aldosteronism or other conditions associated with sodium retention. In moderate and advanced chronic renal disease the serum bicarbonate/mortality relationship is U-shaped — lowest mortality at 26-29 mmol/L, higher mortality below 22 mmol/L and also above 29 mmol/L; frequent monitoring of serum electrolytes and acid-base status is essential and overtreatment must be avoided. No numeric dose reduction for renal impairment is stated.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to sodium bicarbonate or any ingredient of the formulation
Metabolic alkalosis or respiratory alkalosis
Hypokalaemia, hypernatraemia, hypocalcaemia
Patients on a low sodium diet
Hypochlorhydria
Not to be taken by children under 12 years old

Side effects

Gastrointestinal: wind, nausea, vomiting, abdominal discomfort and distension, flatulence, unpleasant taste
Metabolic: metabolic alkalosis, fluid retention, continuing loss of appetite
Vascular/respiratory: hypertension, slow breathing, breathing difficulties, fluid on the lungs
Neurological/psychiatric: continuing headache, dizziness, mood or mental changes, nervousness or restlessness
Renal: frequent urge to urinate; promotion of renal urolithiasis (calcium or magnesium phosphate calculi) on prolonged use
General: swelling of feet or lower legs, extreme irritability, unusual tiredness or weakness, muscle spasms or cramps

Interactions

Alkalinisation of the urine may reduce or increase the effects of a number of drugs and alter elimination of weak acids and bases — e.g. aspirin, diflunisal, sympathomimetics, anticholinergics, tricyclic antidepressants, barbiturates, H2-blockers, captopril and quinidine
Lithium — sodium-containing preparations should be avoided; sodium is preferentially absorbed by the kidney, increasing lithium excretion and reducing plasma lithium levels
Reduced absorption of many concomitant drugs, including ACE inhibitors (captopril, enalapril, fosinopril), quinolones, tetracyclines, azithromycin, cefaclor, cefpodoxime, isoniazid, rifampicin, itraconazole and ketoconazole, atazanavir/fosamprenavir/tipranavir, fexofenadine, bisphosphonates, deflazacort, digoxin, dipyridamole, gabapentin and phenytoin, lansoprazole, levothyroxine, mycophenolate, rosuvastatin, sulpiride and phenothiazines, chloroquine, hydroxychloroquine and penicillamine — separate administrations by approximately 2 to 3 hours
Large amounts of milk or calcium-containing products should not be taken concomitantly — risk of milk-alkali syndrome
Antacids should be avoided with nilotinib (§4.5 was truncated at the source-fetch limit — verify the remainder)

Clinical monograph

How it works

Bicarbonate acts as an alkalinising base, buffering retained hydrogen ions and raising serum bicarbonate towards the normal range. Correcting acidosis is thought to slow muscle catabolism and bone demineralisation seen in CKD.

Prescribing in practice

Each gram delivers a substantial sodium load, so it can worsen fluid retention, oedema and hypertension in CKD and heart failure — use cautiously and review volume status.
Titrate against serum bicarbonate aiming for the low-normal range rather than over-correction, which risks metabolic alkalosis and hypokalaemia.
Separate dosing from other medicines where the rise in gastric and urinary pH could alter absorption, and review concurrently with diuretic and antihypertensive therapy.

Monitoring

Monitor serum bicarbonate, potassium, blood pressure and fluid status, adjusting the dose to maintain bicarbonate within target.

Counselling the patient

Take regularly as prescribed to keep your blood acid level steady.
Report new ankle swelling, breathlessness or rapid weight gain.
Do not double up if a dose is missed.

Evidence & guidelines

NICE CKD guidance and trial data support oral bicarbonate to correct chronic metabolic acidosis and may help preserve renal function, though optimal targets remain debated.

Reference: NICE NG203 (CKD); Cooper et al. Lancet 2020 (BICARBONATE trial); de Brito-Ashurst et al. JASN 2009; ALS Guidelines 2021; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways