Thyroid Capsule

Thyroid Capsules (Desiccated Thyroid / T4–T3 Combination)
Usage
Thyroid capsules are a compounded thyroid hormone replacement therapy containing a combination of thyroxine (T4) and triiodothyronine (T3), often derived from desiccated thyroid extract or customised synthetic blends.
They are used to restore normal thyroid hormone levels in patients with hypothyroidism or selected endocrine conditions.
They may be prescribed for:
• Hypothyroidism
• Patients who do not respond adequately to levothyroxine (T4) alone
• Thyroid hormone replacement after thyroidectomy
• Other practitioner-directed endocrine uses
Compounded capsules allow for individualised T4:T3 ratios tailored to patient needs.

Dosage
Dosage should be individualised and determined by the prescribing practitioner based on symptoms and laboratory results.
Typical dosing considerations include:
• Usually administered once daily
• Taken on an empty stomach, preferably 30–60 minutes before food
• Capsules should be taken with water only
• Dose adjustments are made gradually based on TSH, free T4, and free T3 levels
Consistency in timing and administration is important for optimal absorption.

Mechanisms of Action
Thyroxine (T4)
• Acts as a prohormone, converted in the body to the active hormone T3
Triiodothyronine (T3)
• Directly binds to thyroid hormone receptors to regulate metabolism and cellular activity
Combined Effect
• Restores normal thyroid hormone levels
• Regulates metabolic rate, energy production, and organ function
• Supports cardiovascular, neurological, and musculoskeletal systems

Contraindications
Thyroid capsules should not be used in patients with:
• Untreated thyrotoxicosis (hyperthyroidism)
• Uncorrected adrenal insufficiency
• Hypersensitivity to thyroid hormones or formulation components

Precautions
Thyroid capsules should be used with caution in patients with:
• Cardiovascular disease (e.g., coronary artery disease, arrhythmias)
• Elderly patients, who may require lower initial doses
• Diabetes mellitus, as thyroid hormones may affect glycaemic control
• Adrenal insufficiency
Additional considerations include:
• Over-replacement may cause symptoms of hyperthyroidism:
• Palpitations
• Anxiety
• Weight loss
• Insomnia
• Under-treatment may result in persistent hypothyroid symptoms
• Regular monitoring of thyroid function tests is essential
• Absorption may be affected by certain foods and medications (e.g., calcium, iron)
Patients should seek medical advice if they experience chest pain, rapid heartbeat, or significant symptom changes.

Storage
• Store below 25°C unless otherwise directed
• Keep capsules in a tightly closed container
• Protect from heat, moisture, and light, as thyroid hormones are sensitive to degradation
• Keep out of reach of children and pets
Patients should follow the storage instructions provided on the dispensing label supplied by the pharmacy.