Underdosing of histamine H2-receptor blockers, init encntr

This code signifies that a patient has not received enough of a histamine H2-receptor blocker medication, leading to an adverse effect or a worsening of their underlying condition. This underdosing could be due to various reasons, such as patient non-adherence, incorrect prescription, or insufficient dosage.

Apply this code when documentation clearly indicates that a patient's symptoms or condition (e.g., peptic ulcer, GERD) are exacerbated because they did not take the prescribed amount of an H2-receptor blocker. This is for the initial phase of treatment for the underdosing event.

• Ensure the medical record explicitly states "underdosing" and identifies an H2-receptor blocker as the substance.
• Always sequence this code first, followed by the code for the specific adverse effect or condition resulting from the underdosing.
• Verify that the encounter is the initial one for this particular underdosing event.