ICD-11 Codes
for 3A01.5 - Drug-induced vitamin B12 deficiency anaemia

Teodor Jurukovski January 1, 1970

Fact checked by: Teodor Jurukovski

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Understanding Drug-Induced Vitamin B12 Deficiency Anaemia (ICD-11 Code 3A01.5)

Drug-induced vitamin B12 deficiency anaemia, identified by the ICD-11 code 3A01.5, is a specific type of anaemia resulting from insufficient levels of vitamin B12 in the body, directly caused by the therapeutic use of certain medications. This deficiency impairs the body's ability to produce adequate healthy red blood cells, leading to anaemia. The condition arises when medications interfere with the absorption or utilisation of vitamin B12, which is essential for red blood cell formation, DNA synthesis, and neurological function.

Medications Linked to Vitamin B12 Deficiency

Several classes of medications can contribute to vitamin B12 deficiency by affecting its absorption. Common culprits include metformin, a widely used drug for managing type 2 diabetes, and certain medications prescribed for heartburn and acid reflux, such as proton pump inhibitors (PPIs) and H2-receptor antagonists. These drugs can disrupt the complex physiological processes required for vitamin B12 to be effectively absorbed from the digestive tract. The ICD-11 classification system allows for postcoordination with codes like PL00 (Drugs, medicaments or biological substances associated with injury or harm in therapeutic use) to specify this drug-induced aetiology.

Recognising the Signs of Medication-Related B12 Deficiency

Symptoms of drug-induced vitamin B12 deficiency anaemia can be varied and may overlap with general anaemia symptoms. These include fatigue, paleness, shortness of breath, headaches, and dizziness. Due to vitamin B12's critical role in nerve function, neurological manifestations are also common. Patients may experience tingling or numbness, difficulties with balance and walking, cognitive impairments such as confusion, memory loss, and slowed thinking, as well as mood changes like depression or irritability. Other signs can include glossitis (a sore, red tongue), diarrhoea, and unexplained weight loss.

Diagnosing Drug-Induced Vitamin B12 Deficiency

The diagnostic process for drug-induced vitamin B12 deficiency anaemia typically begins with a thorough medical history, paying close attention to the patient's current medication regimen and reported symptoms. Blood tests are crucial for confirmation. A complete blood count (CBC) helps identify anaemia and assess red blood cell size, often revealing macrocytic anaemia (larger than normal red blood cells). Measuring serum vitamin B12 levels is essential, although levels may sometimes appear normal despite a functional deficiency. Further investigations may include homocysteine and methylmalonic acid (MMA) levels, which are typically elevated in vitamin B12 deficiency.

Managing Vitamin B12 Deficiency Caused by Medications

Treatment for drug-induced vitamin B12 deficiency anaemia focuses on replenishing vitamin B12 levels and, where possible, addressing the causative medication. Vitamin B12 can be administered through oral supplements, nasal sprays, or injections, with the route and dosage determined by the severity of the deficiency. For significant deficiencies, vitamin B12 injections are often initiated to rapidly restore levels. Patients should discuss their symptoms and medication use with their healthcare provider to explore potential adjustments to their treatment plan, such as switching to alternative medications or implementing strategies to mitigate the deficiency's impact. Dietary adjustments can also support overall health.

Other Terms for 3A01.5

The condition identified by ICD-11 code 3A01.5 is also commonly referred to by several other terms, reflecting its cause and the resulting anaemia. These include: Drug-induced vitamin B12 deficiency anaemia, Megaloblastic anaemia due to drug-induced vitamin B12 deficiency, Vitamin B12 deficiency anaemia due to medication, and Medication-induced vitamin B12 deficiency.