Adverse effect of histamine H2-receptor blockers, subs

This code signifies a patient experiencing an unintended and undesirable reaction to a histamine H2-receptor blocker during a follow-up visit. The adverse effect is not due to poisoning, overdose, or improper use, but rather a known or expected side effect of the medication.

Apply this code when a patient presents for ongoing management or evaluation of an adverse reaction to an H2-receptor blocker, such as cimetidine, ranitidine, or famotidine, after the initial treatment for the adverse effect has been provided. This would include scenarios where the patient is being monitored for resolution of symptoms or for adjustments to their medication regimen.

• Always use in conjunction with a code identifying the specific adverse effect (e.g., rash, headache, liver enzyme elevation).
• Ensure documentation clearly states the H2-receptor blocker as the causative agent and that the encounter is for subsequent care.
• Distinguish from initial encounters (T47.0X5A) or sequelae (T47.0X5S) of the adverse effect.