Potassium citrate (K 3 C 6 H 5 O 7 ) is the potassium salt of citric acid (C 6 H 8 O 7 ); in addition to the tripotassic form, potassium citrate can also be found in the dipotassic (K 2 C 6 H 6 O 7 ) and monopotassic (KC 6 H 7 O 7 ) form.
At room temperature, it appears as a white crystalline powder, slightly hygroscopic, odorless and with a saline taste. Both its constituents (potassium and citric acid) are abundantly present in nature and within the human body:
- potassium taken through the diet is very important for the contraction of voluntary muscles, heart and smooth muscles; in addition, it participates in the regulation of acid-base balance and arterial pressure. Many foods contain potassium, such as meat, certain types of fish (such as salmon, cod and plaice), and generally all fruit, vegetables and legumes.
- citric acid is a key molecule of the metabolic processes that take place within each cell of the body (Krebs cycle), and is present in important concentrations in the bones, with a stabilizing function. In addition to being produced by the body, it abounds mainly in citrus fruits, where it is also found in the form of potassium citrate: lemon juice contains 5-7% and the orange is about 1%, but is found in fair concentrations a little in all the fruit, in particular in kiwi and strawberries.
Potassium citrate - or potassium citrate, if you prefer - recognizes applications both in the food industry as an acidity corrector additive, and in the pharmaceutical industry, as an alkalizing compound against the metabolic, gastric and urinary acidosis patterns; the use of potassium citrate in the prevention of urinary stones from excess uric acid, cystine and xanthines is well known.
Potassium citrate as a food additive
In the food field, potassium citrate is used as a buffering agent, acidity corrector, metal ion chelator, and nutrient for yeasts in some fermented foods.
Potassium citrate in drugs and supplements
Potassium citrate recognizes numerous medical and health applications:
- antacid : useful in case of gastric hyperacidity and heartburn, dyspepsias, digestive difficulties and gravid nausea; in fact, being a weak acid, in contact with hydrochloric acid (strong acid) present in the stomach, in an environment characterized by a pH equal to 1.5-3, potassium citrate acts as a base by subtracting hydrogenions from hydrochloric acid to give rise to potassium chloride and citric acid:
- K 3 C 6 H 5 O 7 + HCl => K 2 C 6 H 6 O 7 + KCl
K 2 C 6 H 6 O 7 + HCl => KC 6 H 7 O 7 + KCl
KC 6 H 7 O 7 + HCl => C 6 H 8 O 7 (citric acid) + KCl (potassium chloride)
- potassium supplement : each gram of potassium citrate contains 383 mg of elemental potassium; in this regard, it should be borne in mind that the overall recommended daily intake of potassium (diet + any supplement) is around 4 grams.
Although much more expensive than other sources of potassium (for example potassium chloride), citrate is sometimes preferred for technological reasons (it is suitable for the preparation of effervescent products), for health reasons (see below) or for simple commercial recall;
- alkalizing agent : the intake of potassium citrate is able to increase the urinary pH, thus making the urine more alkaline; this intervention helps prevent the precipitation of uric acid, cystine and xanthine crystals, making them more soluble in urine. It is therefore an important aid in people suffering from this type of urinary calculosis .
- The correction of the excessive acid load can be evaluated directly by measuring the urinary pH with appropriate strips of litmus paper. The urinary pH varies during the day with more significant lowering during the night and in the morning; for this reason it is preferable to measure it especially when awakening. If the urinary pH value is less than 6, it is advisable, if confirmed by the doctor, to make any correction by taking potassium citrate in the morning and in the evening, then checking the urinary alkalinizing action with the appropriate strips. In the presence of urolithiasis it is advisable to maintain the urinary pH between 6.5 and 6.8 to favor the dissolution of uric acid crystals. A daily water intake of 2.5-3 liters is also recommended to favor the dilution of urinary uric acid.
- The alkalizing action of potassium citrate is also used in patients suffering from metabolic acidosis (eg due to chronic renal failure or renal tubular acidosis) to increase blood pH, which is strictly regulated by the body in order to keep it within limits very short. For the same reason, potassium citrate can also be taken to relieve urinary burns associated with minor urinary tract infections
- metabolic acidosis prevention in patients with kidney disease
Side effects and contraindications
Unless otherwise indicated, potassium citrate should be swallowed with water (a 250 ml glass) immediately after meals, in order to dampen the slightly corrosive effect on the teeth and and on the mucosa of the upper digestive tract, which could also be associated with nausea, vomiting, diarrhea and stomach cramps. The intake of potassium citrate together with water is also a stimulus for diuresis: the washing and diluting action of urine is particularly useful in the presence of cystitis and a tendency to urinary calculi.
Among the possible contraindications related to the use of potassium citrate we recall:
kidney failure, hyperkalemia, uncontrolled diabetes, gastric ulcer, adrenal insufficiency (eg Addison's disease), severe burns or other tissue lesions, dehydration, intake of potassium-sparing diuretics (amiloride, spironolactone, triamterene)
Excess potassium can cause asthenia, muscle cramps, hypotension and bradycardia up to cardiac arrest.
In general, it is a good idea to receive the doctor's approval before starting a treatment with potassium citrate on one's own initiative, especially in the presence of:
kidney disease, congestive heart failure, hypertrophic cardiomyopathy, past history of cardiac infarction, other heart disease, diabetes, hypertension, gastric or intestinal obstruction, chronic diarrhea (such as that associated with ulcerative colitis or Crohn's disease);
taking drugs such as ACE inhibitors (eg enalapril), aldosterone blockers (eg eplerenone), or potassium-sparing diuretics (eg triamterene), because they could increase the side effects of potassium citrate, with negative effects especially on the heart;
taking medications such as aluminum salts (some antacids), anticholinergics (eg atropine), anorectics (eg phentermine) or certain stimulants (albuterol, amphetamine, pseudoefredina), due to the risk that their negative effects are enhanced by potassium citrate ;
intake of lithium or tetracycline (eg Doxycycline), because their therapeutic effect could be enhanced by taking potassium citrate.
