Meganerv F-A Special Precautions

The formulation consists of vitamins B1, B6, B9 and B12 which are all water-soluble. Any excess intake will be readily eliminated in the urine, and the formulation is therefore safe for long-term use. Folic acid is usually well tolerated in the dosage prescribed. Folic acid may partially reverse the anti-epileptic effects of phenobarbital, diphenylhydantoin, and primidone, and thereby increase seizure frequency. The combination of folic acid and vitamin B12 makes it safe to use in the treatment of pernicious anemia. Sensitivity to vitamin B1 may sometimes be encountered.
Sensitivity may occur if administration is at prolonged intervals, is irregular, or if the initial dose is low and is suddenly increased. Liver dysfunction also seems to predispose patients to hypersensitivity reactions. Nevertheless, it must be stressed that hypersensitivity to vitamin B1 is very rare when given orally and is encountered more often only when given by intravenous injection.