Working with Ingredients

Learn how to work with pharmaceutical ingredients in the system.

Overview

Ingredients are the active pharmaceutical components of drugs. The ingredients table provides detailed information about ingredient strengths, components, and precise ingredient classifications. This tutorial will guide you through understanding RxNorm's ingredient concepts and how to work with ingredient data effectively.

Multiple Ingredients vs Single Ingredients

RxNorm has two key concepts for ingredients:

1. Multiple ingredients (ingredient type = MIN): Represent combinations of ingredients
2. Single ingredients (ingredient type = IN): Represent individual active ingredients

Single Ingredient Drugs

A drug like lisinopril will be associated with a single ingredient (IN). The ingredient represents the active pharmaceutical ingredient itself.

Multiple Ingredient Drugs

A drug like lisinopril / hydrochlorothiazide will be associated with a multiple ingredient (MIN). This multiple ingredient represents the combination of two or more active ingredients.

Ingredient Components

When a drug is associated with a multiple ingredient (MIN), the ingredients table will have multiple rows - one for each "ingredient component".

The ingredient component represents the lowest level ingredient available in a drug and should always be a single ingredient (IN) concept. The "ingredient" associated to the drug will be the multiple ingredient (MIN) concept.

Example: For lisinopril / hydrochlorothiazide:

• The drug is associated with a multiple ingredient (MIN) representing the combination
• The ingredients table will have two rows:
  • One row for lisinopril (IN) as an ingredient component
  • One row for hydrochlorothiazide (IN) as an ingredient component

Mapping Drugs to Ingredients

Using Clinical Drug ID

It's important to note that we map ingredients to drugs via the clinical_drug_id of the drug table. This is because regardless of whether a drug is brand name or generic, it should have the same clinical ingredients.

Important: Always use clinical_drug_id (not drug_id) when joining from the drugs table to the ingredients table. This ensures you get the correct ingredient mappings for both brand and generic drugs.

Drug Component ID

In certain situations (like "pack" drugs), the drug_component_id column will be different from the drug_id column. Some "pack" drugs will have multiple different drugs that each have their own mappings to ingredients.

Example Query:

-- Join drugs to ingredients using clinical_drug_id
SELECT 
    d.drug_id,
    d.drug_name,
    d.clinical_drug_id,
    i.ingredient_id,
    i.ingredient_name,
    i.ingredient_component_id,
    i.ingredient_component_name
FROM drugs d
JOIN ingredients i ON d.clinical_drug_id = i.drug_id
WHERE d.drug_name LIKE '%lisinopril%'
ORDER BY d.drug_id, i.ingredient_component_id;

Precise Ingredients

In addition to multiple vs single ingredients, there is also the concept of a "precise ingredient". This is important for certain drugs that have different effects based on the salt form of the ingredient.

Example: Metoprolol Salt Forms

For instance, metoprolol tartrate and metoprolol succinate are both a "metoprolol" ingredient - however, they each have different "precise ingredients":

• One is "metoprolol tartrate"
• The other is "metoprolol succinate"

These different salt forms can have different clinical effects, dosing schedules, and pharmacokinetic properties, so it's important to distinguish between them using the precise ingredient.

Example Query:

-- Find all metoprolol products and their precise ingredients
SELECT 
    d.drug_name,
    i.ingredient_name,
    i.ingredient_component_name,
    i.precise_ingredient_name
FROM drugs d
JOIN ingredients i ON d.clinical_drug_id = i.drug_id
WHERE i.ingredient_name LIKE '%metoprolol%'
  AND i.ingredient_type = 'IN'
ORDER BY i.precise_ingredient_name;

Ingredient Strengths

The ingredients table is where you can work with ingredient strengths. Strengths have:

• Numerator value (and numerator unit): The primary strength value (e.g., 500 for "500mg")
• Denominator value (and denominator unit): Used for concentration-based strengths (e.g., 5 for "5mg/5ml")
• Strength text: A human-readable text representation for convenience

Working with Strength Data

You can work with strength data in two ways:

1. Numerically: Use strength_numerator_value, strength_numerator_unit, strength_denominator_value, and strength_denominator_unit for calculations and comparisons
2. Textually: Use strength_text for display and simple matching

Example Queries:

-- Find all drugs with a specific ingredient strength
SELECT 
    d.drug_name,
    i.ingredient_component_name,
    i.strength_text,
    i.strength_numerator_value,
    i.strength_numerator_unit
FROM drugs d
JOIN ingredients i ON d.clinical_drug_id = i.drug_id
WHERE i.ingredient_component_name = 'metformin'
  AND i.strength_numerator_value = 500
  AND i.strength_numerator_unit = 'MG'
ORDER BY d.drug_name;

-- Find all concentration-based strengths (those with denominators)
SELECT 
    d.drug_name,
    i.ingredient_component_name,
    i.strength_text,
    i.strength_numerator_value,
    i.strength_numerator_unit,
    i.strength_denominator_value,
    i.strength_denominator_unit
FROM drugs d
JOIN ingredients i ON d.clinical_drug_id = i.drug_id
WHERE i.strength_denominator_value IS NOT NULL
ORDER BY i.ingredient_component_name, i.strength_text;

Common Patterns

Finding All Ingredients for a Drug

-- Get all ingredient components for a specific drug
SELECT 
    i.ingredient_component_name,
    i.precise_ingredient_name,
    i.strength_text,
    i.ingredient_name AS multiple_ingredient_name
FROM ingredients i
WHERE i.drug_id = 'YOUR_CLINICAL_DRUG_ID'
ORDER BY i.ingredient_component_id;

Finding All Drugs with a Specific Ingredient

-- Find all drugs containing a specific ingredient
SELECT DISTINCT
    d.drug_id,
    d.drug_name,
    d.clinical_drug_id
FROM drugs d
JOIN ingredients i ON d.clinical_drug_id = i.drug_id
WHERE i.ingredient_component_name = 'lisinopril'
ORDER BY d.drug_name;

Finding Multi-Ingredient Drugs

-- Find drugs with multiple ingredient components
SELECT 
    d.drug_id,
    d.drug_name,
    COUNT(DISTINCT i.ingredient_component_id) AS ingredient_count,
    STRING_AGG(i.ingredient_component_name, ' / ') AS ingredients
FROM drugs d
JOIN ingredients i ON d.clinical_drug_id = i.drug_id
GROUP BY d.drug_id, d.drug_name
HAVING COUNT(DISTINCT i.ingredient_component_id) > 1
ORDER BY ingredient_count DESC, d.drug_name;

Best Practices

1. Always use clinical_drug_id when joining from drugs to ingredients table
2. Understand the difference between ingredient (MIN/IN), ingredient component (always IN), and precise ingredient
3. Use ingredient components when you need the lowest-level ingredient information
4. Use precise ingredients when salt forms matter for your analysis
5. Work with strength data numerically when performing calculations or comparisons
6. Use strength_text for display purposes or simple text matching
7. Be aware of drug_component_id differences for pack drugs with multiple components