Cynodex

Indications

Cyanocobalamin is a form of vitamin B12. It is used to prevent and treat vitamin B12 deficiency, which can cause anaemia, tiredness, a sore tongue, numbness or tingling in the hands and feet, memory problems and low mood. Deficiency is more likely in strict vegetarians, older people, people with pernicious anaemia (the stomach cannot absorb B12), after stomach or bowel surgery, and with long-term use of Metformin or stomach acid medicines.

How It Works

Vitamin B12 is needed to make healthy red blood cells and DNA, and to keep the protective covering of nerves healthy. Without it, the bone marrow makes large, poorly working red cells and nerves can be damaged.

Dosage and Administration

• Adults, diet-related deficiency or supplement: usually 50 to 150 mcg a day by mouth; higher oral doses may be prescribed.
• Pernicious anaemia and absorption problems: usually injections, often for life, on a schedule set by the doctor.
• Injections are given by a doctor or nurse.
• Children: as prescribed.

Tablets are best taken between meals, but can be taken with food if they upset the stomach.

Interactions

• Metformin, Omeprazole and other stomach acid medicines, Colchicine and heavy alcohol use reduce B12 absorption over time.
• Chloramphenicol may reduce the blood response to B12.
• Folic acid can hide the blood signs of B12 deficiency while nerve damage continues, so both should be checked.

Contraindications

• Allergy to cyanocobalamin, cobalt or any ingredient of the product.
• Leber's disease (an inherited eye nerve condition): cyanocobalamin should not be used.

Side Effects

Usually well tolerated. Possible effects include mild diarrhoea, itching, headache, and pain or redness at the injection site. In the first days of treating severe anaemia, potassium levels can fall, so the doctor may check blood tests. Get urgent medical help if you notice swelling of the face, lips or throat, difficulty breathing, a widespread rash, chest pain, palpitations or severe muscle weakness.

Pregnancy and Lactation

Safe and important when needed during pregnancy and breastfeeding. Use the dose the doctor advises.

Precautions and Warnings

The cause of B12 deficiency should be found before long-term treatment, and blood counts should be checked. Do not stop prescribed injections for pernicious anaemia, as the deficiency will return. Tell the doctor if you have heart disease or low potassium.

Overdose

Vitamin B12 has very low toxicity and extra amounts pass out in urine. If a large amount has been taken and you feel unwell, seek medical advice.

Therapeutic Class

Vitamin B12 (water-soluble vitamin); used to treat anaemia.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children. Keep injection ampoules in the carton to protect from light.