305.90  Other, mixed, or unspecified drug abuse, unspecified...

This is an nonspecific code.  Your claim COULD be suspended (held up) by insurance companies or third-party payors for further documentation before payment is made.  Also, payment COULD be denied because payors may not be able to determine 'medical necessity' because the code is too generic.  Use EXTREME caution when using this code.  A specific code is a better choice!  If there is no better choice, however, it is always best to review documentation or even consult the physician BEFORE using this code to make sure that you have been as specific as you possibly can.