7.1 Respiratory & Endocrine Therapeutics

7.1 Respiratory & Endocrine Therapeutics

Clinical therapeutics in primary care requires a deep understanding of evidence-based guidelines, disease pathophysiology, and individualized pharmacotherapy. This section details chronic management strategies for asthma, COPD, Type 1 Diabetes (T1DM), and Type 2 Diabetes (T2DM).

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Asthma Step-Wise Management (GINA Guidelines)

The Global Initiative for Asthma (GINA) guidelines fundamentally restructured asthma care by moving away from Short-Acting Beta-2 Agonist (SABA) monotherapy. SABA-only treatment is associated with an increased risk of severe exacerbations and asthma-related mortality due to beta-receptor downregulation and unchecked underlying inflammation.

GINA defines two primary treatment tracks for adults and adolescents:

• Track 1 (Preferred): Uses an anti-inflammatory reliever (low-dose Inhaled Corticosteroid [ICS]-formoterol) as needed across all steps. Formoterol provides rapid bronchodilation combined with simultaneous low-dose anti-inflammatory ICS delivery. This approach is Maintenance and Reliever Therapy (MART).
• Track 2 (Alternative): Uses a SABA (salbutamol) reliever, paired with regular daily ICS maintenance therapy. Indicated only if Track 1 is not feasible.

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COPD Management (GOLD ABE Assessment & Escalation)

Chronic Obstructive Pulmonary Disease (COPD) is characterized by persistent airflow limitation. The GOLD framework stratifies patients into Groups A, B, and E based on symptoms (mMRC or CAT score) and exacerbation history.

GOLD ABE Classification Matrix

• Group A: Low symptoms (mMRC 0-1, CAT <10) AND low exacerbation risk (0-1 moderate exacerbation, no hospital admission).
• Group B: High symptoms (mMRC >=2, CAT >=10) AND low exacerbation risk (0-1 moderate exacerbation, no hospital admission).
• Group E: High exacerbation risk (>=2 moderate exacerbations OR >=1 exacerbation leading to hospital admission).

                  GOLD ABE PHARMACOTHERAPY INITIAL CHOICE
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   Group A: Monotherapy (Bronchodilator: SABA, LABA, or LAMA)
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   Group B: Dual Bronchodilation (LABA + LAMA combination)
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   Group E: Initial Dual Bronchodilation (LABA + LAMA)
            *If Blood Eosinophils >= 300 cells/µL -> Initial Triple (LABA + LAMA + ICS)

Role of Blood Eosinophils in ICS Escalation

ICS should not be used as monotherapy in COPD due to lack of efficacy and pneumonia risk. Blood eosinophil counts guide ICS addition to dual LABA+LAMA therapy:

• Blood Eosinophils >=300 cells/µL: High likelihood of benefit; strongly supports adding ICS (Triple therapy: LABA + LAMA + ICS).
• Blood Eosinophils 100-300 cells/µL: Moderate benefit; consider ICS if persistent exacerbations occur.
• Blood Eosinophils <100 cells/µL: Low benefit; ICS escalation is not recommended.

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Inhaler Device Selection & Technique Checks

Device selection must match patient cognitive capacity, dexterity, and peak inspiratory flow rate (PIFR).

Clinical Note: Patients using ICS devices must rinse their mouth with water and spit it out after every dose to prevent oral candidiasis and dysphonia.

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Type 1 Diabetes Mellitus (T1DM)

T1DM requires lifelong insulin replacement due to autoimmune destruction of pancreatic beta cells.

Basal-Bolus Regimens & Carbohydrate Counting

Standard therapy consists of a basal-bolus regimen:

1. Basal Insulin: Once or twice daily long-acting insulin (degludec, glargine) suppresses hepatic glucose output overnight.
2. Bolus Insulin: Rapid-acting insulin (aspart, lispro) administered 5-15 minutes prior to meals for postprandial glucose control.

Patients calculate mealtime bolus doses using the Insulin-to-Carbohydrate Ratio (ICR) and correct hyperglycemia using the Insulin Sensitivity Factor (ISF): $\text{Total Meal Bolus} = \left( \frac{\text{Carbohydrates (g)}}{\text{ICR}} \right) + \left( \frac{\text{Current BG} - \text{Target BG}}{\text{ISF}} \right)$

Acute Hypoglycaemia Management (Rule of 15)

Hypoglycaemia is defined as blood glucose <4.0 mmol/L.

                  HYPOGLYCAEMIA MANAGEMENT (RULE OF 15)
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   Step 1: Administer 15-20g Fast-Acting Oral Carbohydrate
           (e.g., 200 mL orange juice, 4-5 glucose tablets)
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   Step 2: Wait 15 minutes and re-check Blood Glucose
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   Step 3: Is Blood Glucose < 4.0 mmol/L?
           ├── YES ──> Repeat Step 1 & re-check in 15 min
           └── NO  ──> Give 10-15g Complex Carbohydrate snack
                       (e.g., 1 slice of bread, 2 digestive biscuits)

Severe Hypoglycaemia (Unconscious): Administer IV 20% Glucose (75-100 mL) over 15 minutes, or IM Glucagon 1mg (or Nasal Glucagon 3mg).

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Type 2 Diabetes Mellitus (T2DM) Pharmacotherapy

Modern T2DM management prioritizes glycemic control alongside organ protection.

Glycemic Targets

• Standard Target: <48 mmol/mol (6.5% - 7.0%) for most non-pregnant adults to minimize microvascular complications.
• Relaxed Target: 53-58 mmol/mol (7.0% - 7.5%) in frail elderly patients or those with severe hypoglycemia history.