Drugs that should use with caution in combination with Vitamin C

Drugs that should use with caution in combination with Vitamin C

By wamin Time: 2021-3-5

Vitamin C (also known as ascorbic acid) is common in clinical and daily life. Some types of drugs should not use in combination with vitamin C due to its strong reducing and acidic properties. In order to assure the rational use of drugs, and avoid vitamin c drug interaction, below we list the 7 types of drugs that should use with cautionin combination with vitamin C.

Drugs that should use with caution in combination with Vitamin C



According to the research, the color of solution deepens immediately while using metronidazole injection in combination with vitamin C. Vitamin C content decreases immediately, and metronidazole content decreases significantly after 8 hours.
It is suggested to diluted metronidazole injection with 0.9% sodium chloride injection or glucose infusion 5% first in order to keep content of vitamin C and metronidazole at acceptability limit within 8 hours.


The strong strong reducing and acidic properties of vitamin C accelerate the hydrolysis reaction of penicillin, and brings highly sensitizing impurities.

Alkaline drug

Vitamin C lose activity due to acid base neutralization while use in combination with alkaline drugs such as sodium bicarbonate, sodium glutamate and aminophylline. So do not use alkaline drug with vitamin c to avoid drug interaction


Both vitamin C with aspirin are acidic medicine. The use of vitamin C causes acidification of urine, which reduce the decreasion of aspirin in urine, and increases the drug blood concentration. If use vitamin C together with aspirin, it might cause aspirin poisoning.

Other vitamins

As a strong reducing agent , vitamin C reacts with other vitamins such as vitamin Bs and vitamin K3, and folic acid.

Anticoagulant drugs

Vitamin C are against the anticoagulant effects of heparin and warfarin, leading to shortening of prothrombin time and weakening the effect of anticoagulant drugs.It is suggested to have at least 2 hours interval if while use together.

Other drugs

Long-term heavy use of vitamin C increases the combination of oxalic acid and calcium salt. If vitamin c with calcium tablets for a long time, the risk of gallstones increases.

Combination use of vitamin C and sulfonamides might cause crystaluria and lead to kidney damage.