Vitamin C (Tablets) Instructions for Use

ATC Code

A11GA01 (Ascorbic acid (vitamin C))

Active Substance

Ascorbic acid (Rec.INN registered by WHO)

Clinical-Pharmacological Group

Vitamin preparation

Pharmacotherapeutic Group

Vitamins; ascorbic acid (vitamin C), including combinations; ascorbic acid (vitamin C)

Pharmacological Action

Ascorbic acid is a water-soluble vitamin.

Ascorbic acid is not produced in the human body and is only supplied with food.

With an unbalanced and inadequate diet, a person experiences a deficiency of ascorbic acid.

Ascorbic acid (vitamin C) plays an important role in the regulation of redox processes, carbohydrate metabolism, blood clotting, and tissue regeneration; it increases the body’s resistance to infections, reduces vascular permeability, and decreases the need for vitamins B₁, B₂, A, E, folic acid, and pantothenic acid.

It participates in the metabolism of phenylalanine, tyrosine, folic acid, norepinephrine, histamine, Fe, utilization of carbohydrates, synthesis of lipids, proteins, carnitine, immune reactions, hydroxylation of serotonin, and enhances the absorption of non-heme Fe.

It has antiplatelet and pronounced antioxidant properties.

It regulates the transport of H⁺ in many biochemical reactions, improves the utilization of glucose in the tricarboxylic acid cycle, participates in the formation of tetrahydrofolic acid and tissue regeneration, synthesis of steroid hormones, collagen, and procollagen.

It maintains the colloidal state of the intercellular substance and normal capillary permeability (inhibits hyaluronidase).

It activates proteolytic enzymes, participates in the metabolism of aromatic amino acids, pigments and cholesterol, and promotes the accumulation of glycogen in the liver. By activating respiratory enzymes in the liver, it enhances its detoxification and protein-forming functions, and increases the synthesis of prothrombin.

It improves bile secretion, restores the exocrine function of the pancreas and the incretory function of the thyroid gland.

It regulates immunological reactions (activates the synthesis of antibodies, the C3 component of complement, interferon), promotes phagocytosis, and increases the body’s resistance to infections.

It inhibits the release and accelerates the degradation of histamine, and suppresses the formation of prostaglandins and other mediators of inflammation and allergic reactions.

In low doses (150-250 mg/day orally), it improves the complex-forming function of deferoxamine in chronic intoxication with Fe preparations, leading to increased excretion of the latter.

Pharmacokinetics

Absorption

It is absorbed in the gastrointestinal tract (GIT) (mainly in the jejunum). With an increase in dose to 200 mg, up to 140 mg (70%) is absorbed; with a further increase in dose, absorption decreases (50-20%). GIT diseases (peptic ulcer of the stomach and duodenum, constipation or diarrhea, helminthic invasion, giardiasis), consumption of fresh fruit and vegetable juices, and alkaline drinks reduce the absorption of ascorbate in the intestine.

The concentration of ascorbic acid in plasma is normally approximately 10-20 µg/ml, body stores are about 1.5 g when taking daily recommended doses and 2.5 g when taking 200 mg/day, the time to reach C_max after oral administration is 4 hours.

Distribution

Plasma protein binding is 25%. It easily penetrates into leukocytes, platelets, and then into all tissues; the highest concentration is achieved in glandular organs, leukocytes, liver, and the lens of the eye; it is stored in the posterior lobe of the pituitary gland, adrenal cortex, ocular epithelium, interstitial cells of the seminal glands, ovaries, liver, spleen, pancreas, lungs, kidneys, intestinal wall, heart, muscles, thyroid gland; it crosses the placental barrier. The concentration of ascorbic acid in leukocytes and platelets is higher than in erythrocytes and plasma. In deficient states, the concentration in leukocytes decreases later and more slowly and is considered a better criterion for assessing deficiency than plasma concentration.

Metabolism

It is metabolized mainly in the liver to dehydroascorbic acid and then to oxaloacetic and diketogulonic acids.

Excretion

It is excreted by the kidneys, through the intestines, with sweat, and breast milk in the form of unchanged ascorbate and metabolites.

When prescribed in high doses, the excretion rate increases sharply. Smoking and consumption of ethanol accelerate the destruction of ascorbic acid (conversion to inactive metabolites), sharply reducing body stores. It is removed by hemodialysis.

Indications

For use in adults aged 18 years and over.

Tablets 250 mg

Prevention and treatment of hypo- and avitaminosis C, associated conditions/diseases

• In the complex therapy of ARVI, colds;
• Asthenic conditions;
• During the recovery period after illnesses;
• With increased physical and mental stress;
• During pregnancy.

Tablets 1000 mg

• Treatment of hypo- and avitaminosis C.

ICD codes

Dosage Regimen

Tablets

The drug is taken orally after meals. 1 tablet is dissolved in a glass of water (200 ml).

The tablets should not be swallowed, chewed, or dissolved in the oral cavity.

For prophylactic purposes, the drug Vitamin C should be taken at a dose of 500 mg/day: 1 tablet containing 250 mg of ascorbic acid, 2 times/day.

For therapeutic purposes, the drug is taken at a dose of 1000 mg/day – 1 tablet containing 1000 mg of ascorbic acid, 1 time/day.

During pregnancy, the drug is prescribed at a maximum daily dose of 250 mg for 10-15 days.

The duration of taking the drug is determined by the attending physician.

Adverse Reactions

From the immune system skin rash, skin hyperemia.

Endocrine disorders inhibition of the function of the insular apparatus of the pancreas (hyperglycemia, glucosuria).

From the nervous system with long-term use in high doses (more than 1000 mg) – headache, increased excitability of the central nervous system, insomnia.

From the vascular system with long-term use of large doses – decreased capillary permeability (possible deterioration of tissue trophism, increased blood pressure, hypercoagulation, development of microangiopathies).

From the gastrointestinal tract irritation of the gastrointestinal mucosa, with long-term use in high doses – nausea, vomiting, diarrhea, hyperacid gastritis, ulceration of the gastrointestinal mucosa.

From the kidneys and urinary tract moderate pollakiuria (when taking a dose of more than 600 mg/day), with long-term use in high doses – hyperoxaluria, nephrolithiasis (from calcium oxalate), damage to the glomerular apparatus of the kidneys.

From metabolism hypervitaminosis, with long-term use in high doses – retention of sodium and fluid, disturbance of zinc and copper metabolism.

General disorders feeling of heat.

Laboratory and instrumental data thrombocytosis, hyperprothrombinemia, erythrocytopenia, neutrophilic leukocytosis, hypokalemia.

Reporting of Suspected Adverse Reactions

It is important to report suspected adverse reactions after registration of the drug in order to ensure continuous monitoring of the benefit-risk ratio of the medicinal product. Healthcare professionals are recommended to report any suspected adverse drug reactions through the national adverse reaction reporting systems of the member states of the Eurasian Economic Union.

Contraindications

• Hypersensitivity to ascorbic acid or any of the excipients included in the drug;
• Age under 18 years (for this dosage form);
• Fructose intolerance, sucrose intolerance, sucrase/isomaltase deficiency, glucose-galactose malabsorption syndrome.

For long-term use in high doses (more than 500 mg)

• Phenylketonuria, glucose-6-phosphate dehydrogenase deficiency;
• Diabetes mellitus;
• Hyperoxaluria;
• Oxalate nephrolithiasis; hemochromatosis;
• Thalassemia;
• Pregnancy (for 1000 mg dosage);
• Breastfeeding period (for 1000 mg dosage).

With caution

• Diabetes mellitus;
• Sideroblastic anemia;
• Urolithiasis;
• Renal failure;
• Polycythemia;
• Leukemia;
• Sickle cell anemia;
• Progressive malignant diseases;
• Oxalosis.

Use in Pregnancy and Lactation

Pregnancy

For 250 mg dosage

The minimum daily requirement for ascorbic acid in the II and III trimesters of pregnancy is 60 mg.

Ascorbic acid crosses the placental barrier. It should be borne in mind that the fetus can adapt to high doses of ascorbic acid entering the mother’s body, and then the newborn may develop a “withdrawal” syndrome.

Therefore, during pregnancy, the dose of ascorbic acid should not exceed 300 mg/day.

For 1000 mg dosage

The use of the drug Vitamin C during pregnancy is contraindicated.

Breastfeeding period

For 250 mg dosage

The minimum daily requirement during breastfeeding is 80 mg.

Ascorbic acid passes into breast milk. A nursing mother’s diet containing an adequate amount of ascorbic acid is sufficient to prevent its deficiency in the breastfed infant. Theoretically, there is a danger to the child when the mother takes high doses of ascorbic acid (it is recommended not to exceed the daily requirement for ascorbic acid).

For 1000 mg dosage

The use of the drug Vitamin C during lactation is contraindicated.

Use in Renal Impairment

The drug should be prescribed with caution in hyperoxaluria, oxalosis, urolithiasis.

Long-term use in large doses (more than 500 mg) is contraindicated in hyperoxaluria, nephrolithiasis.

Pediatric Use

The use of the drug in children and adolescents under 18 years of age is contraindicated (for this dosage form).

Special Precautions

Ascorbic acid in high doses enhances the excretion of oxalates, promoting the formation of kidney stones. In adults who have received high doses, and in newborns whose mothers received high doses of ascorbic acid, “rebound” scurvy may be observed. With long-term use of large doses, inhibition of the function of the insular apparatus of the pancreas is possible, so during the drug administration it is necessary to regularly monitor the blood glucose concentration.

Due to the stimulating effect of ascorbic acid on the synthesis of corticosteroid hormones, it is necessary to monitor adrenal function and blood pressure.

In patients with increased iron content in the body, ascorbic acid should be used in minimal doses.

The effectiveness of using ascorbic acid for the prevention of cardiovascular diseases and some types of malignant tumors is currently considered unproven.

Prescribing ascorbic acid to patients with rapidly proliferating and intensively metastasizing tumors may exacerbate the course of the process.

Ascorbic acid as a reducing agent can distort the results of various laboratory tests (content of glucose, bilirubin in blood and urine, activity of liver transaminases and LDH).

Excipients

The medicinal product Vitamin C, 250 mg, contains 11.62 mmol (267.26 mg) of sodium in 1 tablet. This must be taken into account in patients on a sodium-restricted diet.

The medicinal product Vitamin C, 250 mg, contains sucrose. Patients with rare hereditary fructose intolerance, glucose-galactose malabsorption, or sucrase-isomaltase deficiency should not take this drug.

The medicinal product Vitamin C, 1000 mg, contains 12.95 mmol (297.94 mg) of sodium in 1 tablet. This must be taken into account in patients on a sodium-restricted diet.

The medicinal product Vitamin C, 1000 mg, contains sorbitol. Patients with rare hereditary fructose intolerance should not take this drug.

Influence on the ability to drive vehicles and mechanisms

During treatment with the drug, caution should be exercised when driving vehicles and engaging in other potentially hazardous activities due to the possibility of developing side effects.

Overdose

Symptoms with long-term use in high doses (more than 1000 mg/day), nausea, heartburn, diarrhea, irritation of the gastrointestinal mucosa, flatulence, cramping abdominal pain, frequent urination, nephrolithiasis, insomnia, irritability, hypoglycemia are possible.

Treatment symptomatic therapy, forced diuresis.

If any adverse reactions occur, the patient should stop taking the drug and consult a doctor.

Drug Interactions

Increases the concentration of benzylpenicillin and tetracyclines in the blood; at a dose of 1 g/day increases the bioavailability of ethinylestradiol (including that which is part of oral contraceptives).

Improves the absorption of iron preparations in the intestine (converts ferric iron to ferrous), may increase iron excretion when used concomitantly with deferoxamine.

Reduces the effectiveness of heparin and indirect anticoagulants.

Acetylsalicylic acid (ASA), oral contraceptives, fresh juices, and alkaline drinks reduce the absorption and assimilation of ascorbic acid. ASA reduces the absorption of ascorbic acid by approximately 30%.

With simultaneous use with ASA, the urinary excretion of ascorbic acid increases and the excretion of ASA decreases.

Increases the risk of crystalluria with simultaneous use with salicylates and short-acting sulfonamides, slows the renal excretion of acids, increases the excretion of drugs with an alkaline reaction (including alkaloids), reduces the concentration of oral contraceptives in the blood.

Increases the total clearance of ethanol, which, in turn, reduces the concentration of ascorbic acid in the body.

Quinoline drugs, calcium chloride, salicylates, corticosteroids with long-term use deplete the reserves of ascorbic acid.

With simultaneous use, it reduces the chronotropic effect of isoprenaline.

With long-term use or use in high doses, it may disrupt the interaction of disulfiram and ethanol.

In high doses, it increases the renal excretion of mexiletine.

Barbiturates and primidone increase the excretion of ascorbic acid in the urine.

Reduces the therapeutic effect of antipsychotic drugs (neuroleptics) – phenothiazine derivatives, tubular reabsorption of amphetamine and tricyclic antidepressants.

Storage Conditions

The drug should be stored out of the reach of children, at a temperature not exceeding 25°C (77°F) in the consumer packaging.

Shelf Life

The shelf life is 2 years. Do not use after the expiration date printed on the packaging.

Dispensing Status

The drug is available without a prescription.

Important Safety Information

This information is for educational purposes only and does not replace professional medical advice. Always consult your doctor before use. Dosage and side effects may vary. Use only as prescribed.