Preparations containing sodium citrate and citric acid are especially useful when administration of potassium salts is undesirable or contraindicated, while those containing potassium citrate and citric acid are used when administration of sodium salts is undesirable or contraindicated.
Alkalinization of Urine
Citrates are used for alkalinization of urine (as alternatives to sodium bicarbonate) in conditions where long-term maintenance of an alkaline urine is desirable (e.g., management of uric acid and cystine calculi of the urinary tract).
Chronic Metabolic Acidosis
Citrates are used for management of chronic metabolic acidosis associated with conditions such as chronic renal insufficiency or renal tubular acidosis.
Adjuvant in Gout Therapy
Citrates are used as adjuvants to uricosuric agents in gout therapy.
Prevention of Milk Curdling
Sodium citrate has been used to alter cow’s milk so that large hard curds are not formed in the stomach of feeding infants†.
Gastric Acid Neutralization
Some citrate salts (e.g., sodium citrate and citric acid) also used for buffering and neutralizing gastric hydrochloric acid.
Compounding Uses
Sodium citrate and citric acid may be used as a buffer to maintain an approximate pH in various extemporaneous formulations. (See Compatibility under Stability.)
Dosage and Administration
General
Selection of a specific preparation may in part be determined by potassium and sodium content.
Unlike sodium bicarbonate solution, citrate solutions generally are considered highly palatable and pleasant tasting, and may be particularly useful as alkalinizing agents in patients who do not tolerate the taste of sodium bicarbonate oral solution.
Administration
Oral Administration
Dilute oral citrate solutions with adequate amounts of water prior to administration to minimize the risk of GI complications, and follow with additional water after administration; enhance palatability by chilling the solution before administration.
Reconstitute contents of single-dose packets containing potassium citrate and citric acid for oral solution with cool water or juice prior to administration; give additional water or juice after administration.
Administer oral citrate solutions after meals to avoid the saline laxative effect of the drugs as well as upset stomach.
Shake oral solutions well before use, unless otherwise directed.
Reconstitution
Reconstitute contents of single-dose packets containing potassium citrate and citric acid for oral solution with at least 180 mL of cool water or juice prior to administration.
Dosage
Pediatric Patients
General Pediatric Dosage
Potassium Citrate and Citric Acid
Oral
Usually, 5–15 mL of solution, diluted with 1/2 glass of water, after meals and at bedtime.
Do not use single-dose packets of potassium citrate and citric acid for oral solution in pediatric patients, since dosage for these patients can be more easily regulated with the commercially available oral solution. Individualize dosage according to the patient’s tolerance and response.
Sodium Citrate and Citric Acid
Oral
Children ≥2 years of age: Usually, 5–15 mL of solution, diluted in 30–90 mL of water, after meals and at bedtime; individualize dosage according to patient’s tolerance and response. Consult a clinician for use in children <2 years of age.
Tricitrates
Oral
Usually, 5–15 mL 4 times daily, after meals and at bedtime;individualize dosage according to patient’s tolerance and response.
Prevention of Milk Curdling
Sodium Citrate
Oral
Prevention of the formation of large curds in the stomach of feeding infants: Add 100 mg of sodium citrate to each 30 mL of cow’s milk.
Adults
General Adult Dosage
Potassium Citrate and Citric Acid
Oral
Usually, 15–30 mL of solution, diluted with 1 glass of water, after meals and at bedtime. The usual dosage of potassium citrate and citric acid for oral solution is one single-dose packet (containing 3300 mg of potassium citrate monohydrate and 1002 mg of citric acid monohydrate), reconstituted as directed 4 times daily, after meals and at bedtime. Individualize dosage according to patient’s tolerance and response.
Sodium Citrate
Oral
Usually, 1–2 g every 2–4 hours as necessary for alkalinization effect.
Sodium Citrate and Citric Acid
Oral
Usually, 10–30 mL of solution, diluted in 30–90 mL of water, after meals and at bedtime. Individualize dosage according to patient’s tolerance and response.
Tricitrates
Oral
Usually, 15–30 mL of solution diluted in water 4 times daily, after meals and at bedtime. Individualize dosage according to the patient’s tolerance and response.
Gastric Acid Neutralization
Sodium Citrate and Citric Acid
Oral
15 mL of solution, diluted in 15 mL of water, taken as a single dose.
Cautions
Contraindications
Potassium citrate and citric acid (oral solution and for oral solution [Cytra-K Crystals]): Manufacturer states that preparation is contraindicated in severe renal impairment with oliguria or azotemia, untreated Addison’s disease, adynamia episodica hereditaria, acute dehydration, heat cramps, anuria, severe myocardial damage, or hyperkalemia (from any cause).
Sodium citrate and citric acid oral solution (Bicitra®, Cytra-2): Manufacturers state that preparations are contraindicated in patients requiring sodium-restricted diet and those with severe renal impairment.
Sodium citrate and citric acid (Oracit®): Manufacturer states that preparation is contraindicated in severe renal impairment, oliguria or azotemia, untreated Addison’s disease, adynamia episodica hereditaria, acute dehydration, heat cramp, anuria, severe myocardial damage, and hyperkalemia.
Tricitrates oral solution (e.g., Cytra-3): Manufacturer states that preparation is contraindicated in severe renal impairment with oliguria and azotemia, untreated Addison’s disease, and severe myocardial damage.
Warnings/Precautions
Warnings
Electrolyte and Acid-Base Disturbances
Potassium-containing formulations: Large doses may cause hyperkalemia and alkalosis, especially in patients with renal impairment. Listlessness, weakness, mental confusion, and tingling of the extremities may be associated with hyperkalemia.
Sodium-containing formulations: Excessive doses may cause metabolic alkalosis, especially in patients with hypocalcemia or renal impairment. Possible tetany or depression of the heart associated with decreased ionized calcium concentrations may occur with large doses.
General Precautions
Concomitant Disease
Sodium-containing formulations: Use with extreme caution in patients with low urine output (unless patient is closely supervised), CHF, hypertension, renal dysfunction, peripheral or pulmonary edema, or toxemia of pregnancy.
Potassium-containing formulations: Use with extreme caution in patients in whom excessive potassium may cause deleterious effects.
Adequate Patient Evaluation and Monitoring
Evaluate patient’s clinical condition and monitor serum electrolyte concentrations and acid-base balance periodically, especially in patients with renal impairment, to avoid complications.
Laxative Effects
Possible saline laxative effects; dilute citrate solution with water and administer after meals to minimize this effect.
Specific Populations
Pregnancy
Potassium citrate: Category A.
Lactation
Not known whether potassium citrate is distributed into milk. Because potassium freely distributes into and out of milk, use of potassium citrate by nursing woman with normal plasma potassium concentrations should have no adverse effect on nursing infant; milk potassium concentrations may be increased in hyperkalemic women.
Renal Impairment
Use citrates with caution in patients with renal impairment. Monitor serum electrolyte concentrations and acid-base balance to avoid complications (see Warnings/Precautions under Cautions). Manufacturers state that citrates are contraindicated in patients with severe renal impairment (see Contraindications under Cautions).
Common Adverse Effects
Generally well tolerated at recommended dosages in patients with normal renal function and urine output. (See Warnings under Cautions.)
Increased GI absorption of aluminum; risk of aluminum toxicity in patients with chronic kidney disease receiving citrates and aluminum-containing drugs
Avoid concomitant use in patients with chronic kidney disease; sodium bicarbonate may be an alternative if aluminum-containing phosphate binders required
Metabolism of citrates appears to be associated with bicarbonate formation.
Elimination Route
Citrates are excreted in urine, mainly as metabolites; <5% of an oral dose is excreted in the urine unchanged.
Stability
Storage
Oral
Solution
Potassium citrate and citric acid oral solutions (e.g., Cytra-K): Tight, light-resistant containers at 20–25°C; protect from excessive heat or freezing.
Potassium citrate and citric acid for oral solution (Cytra-K Crystals): Protect from excessive heat or freezing.
Sodium citrate and citric acid oral solution (Oracit®): Well-closed containers at 15–30°C.
Sodium citrate and citric acid oral solution (Cytra-2): Tight, light-resistant containers at 20–25°C; protect from freezing.
Sodium citrate and citric acid oral solution (Bicitra®): Tight containers; protect from freezing or excessive heat.
Tricitrates oral solution (e.g., Cytra-3): Tight, light-resistant containers at 20–25°C; protect from excessive heat or freezing.
Compatibility
For information on systemic interactions resulting from concomitant use, see Interactions.
Oral
Solution
May use sodium citrate and citric acid as a buffer to maintain an approximate pH in various extemporaneous formulations. In general, the addition of the following concentration of the drugs should produce a solution buffered to the approximate pH listed:
Citrate Buffer
pH
Citric Acid Monohydrate g/L
Sodium Citrate Dihydrate g/L
2.5
64.4
7.8
3.0
57.4
17.6
3.5
47.6
31.4
4.0
40.6
41.2
4.5
30.8
54.9
5.0
19.6
70.6
5.5
9.8
84.3
6.0
4.2
92.1
6.5
1.8
95.6
Adapted from Schumacher GE. Buffer formulations. Am J Hosp Pharm. 1966; 23:628-9.
Actions
Potassium citrate is absorbed and then appears to be metabolized to potassium bicarbonate, resulting in systemic alkalinization.
Sodium citrate is absorbed and then appears to be metabolized to sodium bicarbonate, resulting in systemic alkalinization.
Sodium citrate has anticoagulant activity; prevents the clotting of blood by forming an undissociated calcium citrate complex, making calcium unavailable to the clotting mechanism. Anticoagulant sodium citrate solution, when added to blood, prevents the clotting of blood and the crenation or swelling of cells. Sterile solution is used as an anticoagulant for banked blood for transfusion and to prepare citrated human plasma and blood for fractionation.
Sodium citrate prevents the curdling of milk by rennin; has been used to alter cow’s milk so that large hard curds are not formed in the stomach of feeding infants.
Advice to Patients
Importance of following instructions for dosage preparation, including reconstitution and/or dilution recommendations. (See Oral Administration under Dosage and Administration.)
Importance of taking drugs only as prescribed, unless otherwise instructed by a clinician.
Importance of taking doses after meals to avoid saline laxative effect.
Importance of women informing their clinician if they are or plan to become pregnant or plan to breast-feed.
Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses.
Importance of informing patients of other important precautionary information. (See Cautions.)
Preparations
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
† Use is not currently included in the labeling approved by the US Food and Drug Administration.
Remember, keep this and all other medicines out of the reach of children,
never share your medicines with others, and use this medication only for the indication prescribed.
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