Ascorbic acid.
Increases the overall clearance of ethanol, which in turn reduces the concentration of ascorbic acid in the body.
Drugs quinoline series, salicylates, glucocorticosteroids with prolonged use deplete the stores of ascorbic acid.
With simultaneous use reduces the chronotropic effect of isoprenaline. With prolonged use or use in high doses, it can disrupt the interaction of disulfiram-ethanol.
In high doses increases the excretion of mexiletine by the kidneys.
Barbiturates and primidon 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. Increases the concentration in the blood of benzylpenicillin and tetracyclines.
Improves absorption in the intestines of iron preparations (converts trivalent iron into bivalent); can increase the excretion of iron with simultaneousapplication with deferoxamine.
Reduces the effectiveness of heparin and indirect anticoagulants.
Acetylsalicylic acid, oral contraceptives, fresh juices and alkaline drink reduce the absorption and absorption of ascorbic acid.
With simultaneous use with acetylsalicylic acid (ASA), urinary excretion of ascorbic acid increases and the excretion of ASA decreases.
ASA reduces the absorption of ascorbic acid by about 30%.
Increases the risk of developing crystalluria in the treatment of salicylates and sulfonamides short-acting, slows the excretion of kidney acids, increases the excretion of drugs that have an alkaline reaction (including alkaloids), reduces the concentration of oral contraceptives in the blood.
Folic acid.
Folic acid - reduces the effect of phenytoin (requires an increase in its dose). Analgesics (long-term therapy), anticonvulsant drugs (incl. phenytoin and carbamazepine), estrogens, oral contraceptives increase the need for folic acid.
Antacids (including preparations containing aluminum and magnesium), colestramine, sulfonamines (incl. sulfasalazine) reduce the absorption of folic acid.
Methotrexate, pyrimethamine, triamterene, trimethoprim inhibit dihydrofolate reductase and reduce the effect of folic acid (instead, patients using these drugs should be prescribed calcium folinate). For the prevention of hypovitaminosis folic acid is the most preferred balanced diet. Foods rich in folic acid - green vegetables (lettuce, spinach, tomatoes, carrots), fresh liver, legumes, beets, eggs, cheese, nuts, cereals.
Folic acid is not used for treatment In 12-deficiency anemia (pernicious), normocytic and aplastic anemia, as well as anemia refractory to therapy.
With pernicious anemia folic acid, improving hematologic indices, masks neurological complications. While pernicious anemia is not ruled out, administration of folic acid in doses exceeding 0.4 mg / day is not recommended (except for pregnancy and lactation period).
There is evidence that the administration of folic acid during the period of pregnancy planning or early terms may lead to a reduction in the risk of developing neural tube in the fetus.
It should be borne in mind that patients on hemodialysis,require increased amounts of folic acid.
During treatment, antacids should be used 2 hours after taking folic acid, colestramine - 4-6 hours before or 1 hour after taking folic acid. It should be noted that antibiotics can distort (give knowingly underestimated indicators) the results of a microbiological evaluation of the concentration of folic acid in plasma and erythrocytes.
When using large doses of folic acid, as well as therapy for a long period, a decrease in the concentration of vitamin B12 is possible.