Underdosing of other parasympathomimetics, sequela

This code indicates a patient is experiencing long-term or residual effects from having previously taken an insufficient amount of a parasympathomimetic (cholinergic) medication. These medications are typically used to treat conditions like myasthenia gravis, Alzheimer's disease, or glaucoma. The underdosing event itself is in the past, and the current clinical presentation is a direct consequence of that past inadequate dosage.

Use this code when documenting a patient's current symptoms or conditions that are a direct result of a historical underdosing of a cholinergic drug. This would apply, for example, if a patient with myasthenia gravis presents with chronic muscle weakness attributed to a prolonged period of insufficient pyridostigmine dosage in the past. It is appropriate for follow-up encounters where the sequela are being managed.

• Always assign an additional code(s) to specify the nature of the sequela (e.g., specific symptoms or conditions).
• This "S" seventh character indicates a sequela, meaning the initial underdosing event has already occurred and the patient is now experiencing the residual effects.
• Do not use this code for acute underdosing events; use the appropriate acute underdosing code for the initial encounter.