Toxic reaction to local anesth during preg, first trimester

This code describes an adverse systemic response to a local anesthetic agent administered during the first trimester of pregnancy. This reaction is due to the toxic effects of the drug itself, rather than an allergic response or an error in administration. Symptoms can range from mild (e.g., dizziness, tinnitus) to severe (e.g., seizures, cardiac arrest).

Use this code when documentation clearly indicates a toxic reaction to a local anesthetic in a pregnant patient during her first trimester. This typically occurs following procedures such as dental work, minor surgical interventions, or regional blocks where local anesthetics are employed. Documentation should specify "toxic reaction" and the trimester of pregnancy.

• Differentiate from allergic reactions (T78.4-) or adverse effects from correct substance administered correctly (T40-T50 with fifth or sixth character 5).
• Ensure the documentation explicitly states "first trimester" to support the final character '1'.
• Code the specific manifestation of the toxic reaction (e.g., convulsions, cardiac arrhythmia) as an additional diagnosis.