COMPOUNDINGHOTLINE Martin A. Erickson, III, RPh
Q Do you have any information (or a recipe) on vancomycin enemas? Our gastrointestinal (GI) specialist wrote an order for them for a patient with extensive pseudomembranous colitis.
A Anecdotal reports of the use of vancomycin enemas as alternative treatment for this condition indicate positive results.The vancomycin HCl has generally been compounded as 500 mg in 1000 mL of 0.9% sodium chloride for injection. Other reports of use of these retention enema formulations varied from 1 g of vancomycin HCl in 1000 mL of 0.9% sodium chloride for injection q6h to 500 mg vancomycin HCl in 500 mL 0.9% sodium chloride for injection bid. The solution should be freshly prepared, if no preservative is present.
Q I have a 2-month-old patient who has maple syrup urine disease. The physician wants the patient to have 300 mg of thiamine (vitamin B1) each day. Currently, the mom and dad are trying to dissolve 3 x 100-mg tablets in water. Do you have a formula for preparing thiamine suspension?
A Thiamine HCl occurs as colorless-to-white crystals or as a white crystalline powder, has a bitter taste, and is soluble approximately 1 g in 1 mL of water. In solution, it is incompatible with reducing agents such as sulfites; the resultant molecular cleavage increases with increased pH. Also, reports that it degrades in the presence of amino acids in solution with thiosulfites have been found. When the concentration of sulfite did not exceed 0.05%, thiamine was more stable. The drug is well absorbed from the GI tract, following oral administration. The US Pharmacopeia has an official monograph for an elixir of thiamine HCl, but, because this patient is a child, it seems reasonable to suggest compounding an aqueous solution and to suggest the use of a syrup, such as simple syrup, as a base for the preparation. After compounding the thiamine HCl in syrup, the pH should be adjusted to less than 4 with HCl.
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