The answer

The situation regarding nystatin oral suspension is a little confusing, with different information given depending on the source that is referred to. Tanya is presumably dispensing a generic bottle of the antifungal agent, which states the dose as 1ml four times a day. However, the British National Formulary (and the BNF for Children) and the summary of product characteristics (SPC) for Nystan Oral Suspension – the branded version of the product – states the dose in oral candidiasis (thrush) as 1ml qds for babies up to one month old, 2ml qds for infants aged one month to two years, and 4-6ml qds for children aged over two years and adults.

The Nystan SPC was updated in September 2015, with both editions of the BNF changed to reflect the new dosing instructions the following summer. The alteration reflected the opinion of experts in the field, as there is little direct evidence supporting the use of several antifungal agents in the treatment of oral candidiasis. It also brought the UK in line with the US, where higher doses have been used for many years as the 1ml dose has been considered insufficient to coat the inside of the mouth and therefore exert its effect.

Tanya’s most sensible course of action is to phone the medical information department of the pharmaceutical company that makes the product she is dispensing for further advice.