Indications
Vitamin B complex preparations contain a mix of B vitamins, usually Thiamine (B1), Riboflavin (B2), Nicotinamide (B3), Pantothenic acid (B5), Pyridoxine (B6) and sometimes Vitamin B12. They are used to prevent and treat B vitamin deficiency, which can happen with poor diet, alcohol use, long illness, recovery after surgery, pregnancy and breastfeeding, diarrhoea or poor absorption. Injectable and intravenous forms are used in hospital for people who cannot take vitamins by mouth or need them quickly.
How It Works
B vitamins act as helpers (coenzymes) for many chemical reactions in the body. They help turn food into energy, keep nerves and skin healthy, support the making of red blood cells and help the brain and heart work normally. Topping up low levels corrects deficiency symptoms such as tiredness, mouth sores, cracked lips and tingling of the hands and feet.
Dosage and Administration
Tablets, capsules or syrup: take as directed on the label, usually once or twice a day after food. Injections and intravenous infusions are given only by a doctor or nurse, at the dose and frequency prescribed. Do not take more than the recommended amount unless your doctor advises it.
Interactions
- Levodopa: Pyridoxine (B6) can reduce its effect when Levodopa is taken without Carbidopa.
- Phenytoin and Phenobarbital: high doses of B6 may lower their levels.
- Alcohol, some antibiotics, Metformin, acid-reducing medicines and anticonvulsants can lower B vitamin levels.
- Chloramphenicol may reduce the response to Vitamin B12.
Contraindications
- Allergy to any B vitamin or other ingredient (allergy to Thiamine injection is rare but can be serious).
- Products with Vitamin B12 should not be used for undiagnosed anaemia before the cause is known, as it can hide B12 deficiency or Folic acid deficiency.
Side Effects
B complex is usually well tolerated. Bright yellow urine (from Riboflavin) is harmless. Mild nausea, stomach upset or flushing may occur. Injections may cause pain at the site. Very high doses of Pyridoxine taken for a long time can cause nerve damage with numbness.
Get urgent medical help if, especially after an injection, there is swelling of the face, lips or throat, difficulty breathing, widespread rash or collapse.
Pregnancy and Lactation
B vitamins in normal recommended amounts are safe and often needed in pregnancy and breastfeeding. Avoid high-dose products unless prescribed.
Precautions and Warnings
Supplements do not replace a balanced diet. Tell your doctor about long-term use of high doses. Injections should be given slowly by trained staff where treatment for allergic reactions is available. Keep out of the reach of children.
Overdose
Most B vitamins are water soluble and excess is passed in urine, so serious overdose is uncommon. Very large or long-term doses may cause nerve symptoms (B6) or flushing (Nicotinamide). Seek medical advice if a large amount is taken.
Therapeutic Class
Vitamin preparation; vitamin B complex.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Injections: store as directed on the pack.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.