T46.1X5A Adverse effect of calcium-channel blockers, initial encounter

ICD-10-CM T46.1X5A: Adverse effect of calcium-channel blockers, initial encounter

ICD-10-CM code T46.1X5A identifies an adverse effect of calcium-channel blockers during an initial encounter, classified under the semantic type of injury or poisoning. Calcium channel blockers are frequently prescribed cardiovascular medications that block L-type calcium channels, and toxicity can produce myocardial depression, impaired conduction, vasodilation, and hypoinsulinemia. 1 2

Plain-language overview

Code T46.1X5A is an active terminology record for the adverse effect of calcium-channel blockers during an initial encounter, and its semantic type is injury or poisoning. 1

What this code represents

The code T46.1X5A represents a medication adverse effect management event documented as an initial encounter within the S00-T88 chapter of the ICD-10-CM coding system. 5

Coding details

The parent concept for T46.1X5A is T46.1X5, defined as the adverse effect of calcium-channel blockers, and the terminology record includes narrower concepts. 1

The code T46.1X5A is distinguished from T46.1X5S, which designates the sequela of an adverse effect of calcium-channel blockers rather than the initial encounter. 3

Clinical context

Calcium channel blockers are frequently prescribed cardiovascular medications in adults, and toxicity results from excessive blockade of L-type calcium channels. 2

Toxicity from calcium channel blockers produces myocardial depression, impaired conduction, vasodilation, and hypoinsulinemia due to reduced calcium-dependent contractility. 2

Documentation considerations

Clinicians link T46.1X5A to objective findings, time course, and plan of care, while chart review supports decision continuity from triage through discharge. 5

What the sources add

While the terminology record establishes the official code label and hierarchy, the clinical source details the physiological mechanisms of calcium channel blocker toxicity that produce adverse effects. 1 2

The billing and coding article lists T46.1X5A alongside T46.1X5S, confirming the distinction between the initial encounter and sequela encounters for this adverse effect. 3

Sources

1. ICD-10-CM T46.1X5A terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-27.
3. Article - Billing and Coding: RAST Type Tests (A56844) — cms.gov; accessed 2026-07-27.
4. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.
5. Adverse Effect Of Calcium-Channel Blockers, Initial Encounter | ICD-10-CM T46.1X5A Clinical Guide — sprypt.com; accessed 2026-07-27.