This guidance describes the Food and Drug Administration’s (FDA, we, or the Agency) policy concerning the conditions under which the Agency does not generally intend to take regulatory action against a licensed pharmacist in a State-licensed pharmacy or Federal facility or a licensed physician using the bulk drug substance oxitriptan (also known as 5-hydroxytryptophan or 5-HTP) to compound oral drug products for patients with tetrahydrobiopterin (BH4) deficiency. , On February 19, 2019, FDA issued a final rule (84 FR 4696) (“final rule”) that established the list of bulk drug substances that can be used to compound drug products under section 503A of the Federal Food, Drug, and Cosmetic Act (FD&C Act), even though they are not the subject of an applicable United States Pharmacopoeia (USP) or National Formulary (NF) monograph or a component of an FDA approved drug product (503A Bulks List). The final rule, codified at 21 CFR 216.23, placed six bulk drug substances on the 503A Bulks List (21 CFR 216.23(a)), and identified four others, including oxitriptan, that cannot be used to compound drug products under section 503A of the FD&C Act (21 CFR 216.23(b)). Additional bulk drug substances nominated by the public for inclusion on this list are currently under consideration and will be the subject of future rulemaking.
