The facts about vitamin D
Test your knowledge of unlicensed vitamin D products and separate the facts from the fiction
1. Vitamin D refers to a single biochemical entity. True/false?
2. The reimbursement price of unlicensed colecalciferol oral solutions is listed in Part VIIIB of the Drug Tariff. True/false?
3. If you are presented with a prescription for calciferol, then you may only dispense ergocalciferol. True/false?
4. All patients taking vitamin D need to have their plasma-calcium concentration checked. True/false?
5. Renal failure patients requiring vitamin D should be prescribed alfacalcidol or calcitriol. True/false?
6. When supplying vitamin D preparations it is relevant to enquire whether the patient has special dietary requirements. True/false?
7. Unlicensed vitamin D preparations are usually used in cases of severe deficiency caused by comorbid medical conditions. True/false?
1. False: The term vitamin D is used for a range of compounds that possess the property of curing or preventing rickets. They include ergocalciferol (calciferol, vitamin D2), colecalciferol (vitamin D3), dihydrotachysterol, alfacalcidol (1α hydroxycholecalciferol), and calcitriol (1,25-dihydroxycholecalciferol).
2. True: The following oral solutions will only be reimbursed at the price stated in this section of the Drug Tariff: colecalciferol 10,000units/5ml oral solution, colecalciferol 15,000units/5ml oral solution, colecalciferol 20,000units/ml oral solution and colecalciferol 5,000units/5ml oral solution.
3. False: The BP directs that when calciferol is prescribed, colecalciferol or ergocalciferol could be supplied.
4. False: Only those patients receiving pharmacological doses of vitamin D should have their plasma-calcium concentration checked at intervals (initially once or twice weekly) and when nausea or vomiting occur.
5. True: Vitamin D requires hydroxylation by the kidney to its active form, ie alfacalcidol or calcitriol, so where there is renal impairment this hydroxylation is not possible.
6. True: Ergocalciferol is derived from the common plant steroid ergosterol, whereas colecalciferol is produced from the precursor 7-dehydrocholesterol, which is most commonly derived from an animal source such as sheep's wool fat. Colecalciferol products derived from wool fat are not acceptable to vegans and may also be unacceptable to vegetarians if the wool fat is from slaughtered animals. Other excipients such as magnesium stearate should also be taken into account when considering the suitability of products in vegetarians and vegans as it can be produced from either a vegetable or animal source. (UKMi). Fultium D3 gelatin capsules have been certified as being halal, which would make them suitable for Muslim patients.
7. True: Unlicensed vitamin D preparations are usually needed when treatment at pharmacological doses is required, for example, in vitamin D deficiency caused by intestinal malabsorption or chronic liver disease up to 40,000 units may be required daily. There are no licensed preparations for these amounts since most licensed preparations contain vitamin D at 400 or 800 units.
References and sources
● BMJ Group, RCPCH Publications Ltd, Royal Pharmaceutical Society of Great Britain, 2014. British National Formulary. (Accessed 01/07/14)
● Datapharm communications Ltd, 2010. Medikinet XL. Available at: http://www.medicines.org.uk/emc/medicine/19510/SPC/Medikinet+XL (Accessed 01/07/14)
● Patient.co.uk (2014) Attention Deficit Hyperactivity Disorder. Available at: http://www.patient.co.uk/doctor/attention-deficit-hyperactivity-disorder-pro#ref-4 (Accessed 01/07/14)
Samir Vohra MFRPSII FHEA is a lecturer in clinical pharmacy at the School of Pharmacy, University of Central Lancashire