Posology : מינונים

4.2 Posology and method of administration
This medicinal product should be administered only by authorized healthcare professionals in designated clinical settings (see section 6.6).

Posology

The activity to be administered is a matter of clinical judgement. The therapeutic effect is only achieved after several weeks. The activity of the capsule should be determined before use.

Adults

Treatment of hyperthyroidism
In case of failure or impossibility to pursue the medical treatment, radioactive iodide may be administered to treat the hyperthyroidism.
Patients should be rendered euthyroid medically whenever possible before giving radioiodine treatment for hyperthyroidism.

The activity to be administered depends on the diagnosis, the size of the gland, thyroid uptake and iodine clearance. It is usually in the range of 200-800 MBq for a patient of average weight (70 kg) but repeated treatment up to a cumulative dose of 5000 MBq may be necessary. Re-treatment after 6-12 months is indicated for persisting hyperthyroidism.

The activity to be administered may be defined by fixed dose protocols or may be calculated according to the following equation:

A (MBq) =     Target dose (Gy) x target volume (ml)            XK max. uptake I-131 (%) x effective T 1/2 (days)
 under the following conditions target dose          is the target absorbed dose in the whole thyroid gland or in an adenoma  target volume          is the volume of the whole thyroid gland (Graves’ disease, multifocal or disseminated autonomy)
 max. uptake I-131      is the max. uptake of I-131 in the thyroid gland or nodules in % of the administered activity as established in a test dose
 effective T 1/2        is the effective half- life of I-131 in the thyroid gland expressed in days 
K                      is 24.67

The following target organ doses may be used:
Unifocal autonomy                 300 – 400 Gy target organ dose
Multifocal and disseminated          150 – 200 Gy target organ dose Autonomy

Graves’ disease                      200 Gy target organ dose

In the case of Graves’ disease, multifocal or disseminated autonomy, the above mentioned target organ doses are related to the overall volume of the thyroid gland mass, however in the case of unifocal autonomy, the target organ dose is only related to the volume of the adenoma.
For recommended doses to target organs, see section 11.

Other dosimetric procedures may also be used including sodium pertechnetate (99mTc) thyroid uptake tests to determine the appropriate target organ dose (Gy).

Thyroid ablation and treatment of metastases

The activities to be administered following total or sub total thyroidectomy to ablate remaining thyroid tissue are in the range of 1850-3700 MBq. It depends on the remnant size and radioiodine uptake. For treatment for metastases, administered activity is in the range 3700-11100 MBq.
Special populations

Renal impairment

Careful consideration of the activity to be administered is required since an increased radiation exposure is possible in patients with reduced renal function. The therapeutic use of sodium iodide (131I) in patients with significant renal impairment requires special attention (see section 4.4).

Paediatric population

The use of sodium iodide (131I) in children and adolescents has to be considered carefully, based upon clinical needs and assessing the benefit/risk ratio in this patient group.

In certain cases the activity to be administered in children and adolescents should be determined after performing an individual dosimetry (see section 4.4).

In children and adolescents, treatment of benign thyroid defects with radioactive iodide is possible in justified cases, in particular in case of relapse after the use of antithyroid medicinal products or in case of severe adverse reaction to antithyroid medicinal products (see section 4.4).

Method of administration

Theracap is for oral use. The capsule should be taken on an empty stomach. The should be swallowed whole with abundant drink to ensure clear passage into the stomach and upper small intestine.

In case of administration to children, especially to younger children, it must be ensured that the capsule can be swallowed whole without chewing. It is recommended to give the capsule with mashed food.

For patient preparation, see section 4.4..