0071483446.pdf

(^146) CHAPTER 9 Vitamins and Minerals
Deficiency conditions Thiamine:sensory disturbances, retarded growth, fatigue, anorexia
Riboflavin:visual defects such as blurred vision and photophobia,
cheilosis, rash on nose; numbness of extremities
Niacin or nicotinic acid:retarded growth, pellagra, headache,
memory loss, anorexia, insomnia
Pyridoxine:neuritis, convulsions, dermatitis, anemia, lymphopenia
Side effects Thiamine:Raised skin rash, pruritus, or wheezing after a large
IV dose;
Riboflavin:orange-yellow discoloration in urine
Niacin or nicotinic acid:flushing, pruritus, feelings of warmth;
high doses: dizziness, arrhythmias, dry skin, hyperglycemia,
myalgia, nausea, vomiting, diarrhea
Pyridoxine:Occasional: Stinging at IM injection site;
Rare: headache, nausea, somnolence; high doses cause sensory
neuropathy (paresthesia, unstable gait, clumsiness of hands)
Adverse reactions Thiamine:rare anaphylaxis after a large IV dose
Riboflavin:none known
Niacin or nicotinic acid:Cardiac arrythmias may occur rarely
Pyridoxine:Long-term megadoses may produce sensory neuropathy
Contraindications Thiamine:patients with renal dysfunction
Riboflavin:patients with renal dysfunction
Niacin or nicotinic acid:hypersensitivity to niacin or tartrazine;
active peptic ulcer, severe hypotension, hepatic dysfunction, arte-
rial hemorrhaging;
Caution: diabetes mellitus, gallbladder disease, gout, history of
jaundice or liver disease.
Pyridoxine:IV therapy in cardiac patients;
Caution: megadosage in pregnancy
Vitamin B Complex (continued)
Folic Acid (Folate, Vitamin B 9 )
Folic acid is essential for body growth and is needed to synthesize DNA. Folic
acid is found in leafy green vegetables, yellow fruits and vegetables, yeast, and
meat and is absorbed in the small intestine. The active form of folic acid—called
folate—circulates to all tissues in the body. A third of folate is stored in the liver
and the remainder is stored in other tissues. Most folic acid is excreted in bile