Adverse effect of hydantoin derivatives, sequela

This code signifies a long-term or residual condition resulting from a past adverse reaction to hydantoin derivatives, a class of anticonvulsant medications. It indicates that the patient is experiencing ongoing health issues directly attributable to a previous negative effect of these drugs, even after the acute event has resolved.

Use this code when documenting a permanent or chronic sequela, such as persistent neurological deficits, organ damage, or dermatological conditions, that are clearly linked to a prior adverse effect of hydantoin derivatives. This applies when the acute adverse event is no longer active but its lasting consequences are being treated or monitored.

• Always sequence this code after the code describing the specific sequela (e.g., a code for chronic liver disease, peripheral neuropathy).
• Ensure documentation clearly links the current condition to a past adverse effect of hydantoin derivatives, not an active one.
• Do not use this code for acute adverse effects; use the appropriate acute adverse effect code from the T42.0 category instead.