Hydroxocobalamin

Cynomin-H is indicated in-

Addisonian Pernicious anaemia.

Prophylaxis and treatment of other macrocytic anaemias associated with vitamin B12 deficiency.

Schilling test to investigate vitamin B12 absorption and deficiency states.

Hydroxocobalamin (Vitamin B12) is a water-soluble vitamin. It is readily converted into the coenzyme forms which, as methylcobalamin, is concerned with the conversion of homocysteine to methionine, and as deoxyadenosylcobalamin, in the conversion of methylmalonyl-CoA to succinyl CoA. The active coenzymes, methylcobalamin and 5-deoxyadenosylcobalamin, are essential for cell growth and replication.

The following dosage schemes are suitable for adults and children. Addisonian pernicious anaemia and other macrocytic anaemias without neurological involvement:

Initial dose: 250 to 1,000 microgram intramuscularly on alternate days for one to two weeks, then 250 microgram weekly until the blood count is normal.

Maintenance dose: 1,000 microgram monthly.

Addisonian pernicious anaemia and other macrocytic anaemias, anaemias with neurological complications:

Initial dose: 1,000 microgram intramuscularly on alternate days as long as improvement is occurring.

Maintenance dose : 1,000 microgram monthly.

Prophylaxis of macrocytic anaemia associated with vitamin B12 deficiency resulting from gastrectomy, some malabsorption syndromes and strict vegetarianism : 250 to 1,000 microgram monthly. Schilling test : An intramuscular injection of 1,000 microgram Hydroxocobalamin is an essential part of this test.

Biguanides, para-aminosalicylic acid, potassium supplements, cholestyramine, colchicine, neomycin, ethanol, and anticonvulsant drugs have been found to impair cobalamin absorption. Reduced serum cobalamin levels have been reported in patients on anticonvulsant drugs and in women taking oral contraceptives. Antimetabolites and most antibiotics invalidate vitamin B12 assays by microbiological technique. Chloramphenicol treated patients may respond poorly to cyanocobalamin therapy.

Anaphylactic reaction, tobacco amblyopia.

Sensitisation to Cynomin-H is rare but it may present as an itching exanthema, chills, fever, hot flushes, nausea and dizziness and exceptionally as anaphylactic shock. Acneiform and bullous eruptions have been reported rarely.

It should not be used for the treatment of megaloblastic anaemia of pregnancy.

Cynomin-H should, if possible, not be given to patients without first confirming the diagnosis. The dosage schemes given above are usually satisfactory, but regular examination of the blood is advisable. If megaloblastic anaemia fails to respond to it, folate metabolism should be investigated. Doses in excess of 10 micrograms daily may produce a haematological response in patients with folate deficiency. Indiscriminate administration may mask the true diagnosis. Cardiac arrhythmias secondary to hypokalaemia during initial therapy have been reported. Plasma potassium should therefore be monitored during this period.

Keep below 30°C temperature, away from light & moisture. Keep out of the reach of children.