Here are a few reasons why this might happen: Sales tax: The state in which your local network pharmacy is located might charge sales tax in addition to the prescription price
10.1007/s00418-018-1649-x [DOI] [PubMed] [Google Scholar] Tan D., Wen J., Li L., Wang X., Qian C., Pan M., et al
After Reconstitution: Store at 28C and discard after 14 days
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This attrition is what scientists call the Hayflick limit, named after Leonard Hayflick, who discovered that normal human cells divide roughly 4060 times before stopping [23]
The short answer is that there is no established clinically significant interaction documented in UK prescribing information between these two medicines