Chronic hypoparathyroidism

Active Ingredient: Parathyroid hormone

Indication for Parathyroid hormone

Population group: only adults (18 - 65 years old)
Therapeutic intent: Adjunct intent

Parathyroid hormone is indicated as adjunctive treatment of adult patients with chronic hypoparathyroidism who cannot be adequately controlled with standard therapy alone.

For this indication, competent medicine agencies globally authorize below treatments:

50 ug once daily

For:

Dosage regimens

Subcutaneous, 50 micrograms parathyroid hormone, once daily.

Detailed description

Initiating parathyroid hormone

1. Initiate treatment with 50 micrograms once daily as a subcutaneous injection in the thigh (alternate thigh every day). If pre-dose serum calcium is >2.25 mmol/L, a starting dose of 25 micrograms can be considered.

2. In patients using active vitamin D, decrease the dose of active vitamin D by 50%, if pre-dose serum calcium is above 1.87 mmol/L.

3. In patients using calcium supplements, maintain calcium supplement dose.

4. Measure pre-dose serum calcium concentration within 2 to 5 days. If pre-dose serum calcium is below 1.87 mmol/L or above 2.55 mmol/L, this measurement should be repeated the following day.

5. Adjust dose of active vitamin D or calcium supplement or both based on serum calcium value and clinical assessment (i.e., signs and symptoms of hypocalcaemia or hypercalcaemia). Suggested adjustments to parathyroid hormone, active vitamin D and calcium supplements based on serum calcium levels are provided below:

Pre-dose serum
calcium
Adjust first Adjust second Adjust third
Parathyroid hormone Active vitamin D
forms
Calcium supplement
Above the upper limit
of normal (ULN)
(2.55 mmol/L)*
Consider reducing or
stopping parathyroid hormone and
re-assess by means of
serum calcium
measurement
Decrease or
discontinue**
Decrease
Greater than
2.25 mmol/L and below the upper limit of
normal (2.55 mmol/L)*
Consider reductionDecrease or
discontinue**
No change, or decrease
if active vitamin D was
already discontinued
before this titration step
Less than or equal to
2.25 mmol/L and
above 2 mmol/L
No changeNo changeNo change
Lower than 2 mmol/LConsider increase after
at least 2-4 weeks at a
stable dose
IncreaseIncrease

* The value of ULN may vary by laboratory
** Discontinue in patients receiving the lowest available dose

6. Repeat steps 4 and 5 until target pre-dose serum calcium concentration is within the range of 2.0-2.25 mmol/L, active vitamin D has been discontinued and calcium supplementation is sufficient to meet daily requirements.

Parathyroid hormone dosage adjustments after the initiation period

Serum calcium concentration must be monitored during titration.

The dose of parathyroid hormone may be increased by 25 microgram increments approximately every 2 to 4 weeks, up to a maximum daily dose of 100 micrograms. Downward titration to a minimum of 25 micrograms can occur at any time.

It is recommended to measure the albumin-corrected serum calcium 8-12 hours after dosing parathyroid hormone. If post-dose serum calcium is >ULN, then first reduce active vitamin D and calcium supplements and monitor progress. Measurements of pre- and post-dose serum calcium should be repeated and confirmed to be within an acceptable range before titration to a higher dose of parathyroid hormone is considered. If post-dose serum calcium remains >ULN, oral calcium supplementation should be further reduced or discontinued (see also adjustment table under Initiating parathyroid hormone).

At any dose level of parathyroid hormone, if post-dose albumin-corrected serum calcium exceeds the ULN and all active vitamin D and oral calcium have been withheld, or symptoms suggesting hypercalcaemia are present, the dose of parathyroid hormone should be reduced.

Missed dose

In the case of a missed dose, parathyroid hormone must be administered as soon as reasonably feasible and additional exogenous sources of calcium and/or active vitamin D must be taken based on symptoms of hypocalcaemia.

Interruption or discontinuation of treatment

Abrupt interruption or discontinuation of parathyroid hormone can result in severe hypocalcaemia. Temporary or permanent discontinuation of parathyroid hormone treatment must be accompanied by monitoring of serum calcium levels and adjustment, as necessary, of exogenous calcium and/or active vitamin D.

Dosage considerations

Each dose must be administered as a subcutaneous injection once a day in alternating thighs.

It must not be administered intravenously or intramuscularly.

Active ingredient

Parathyroid hormone

Endogenous parathyroid hormone (PTH) is secreted by the parathyroid glands as a polypeptide of 84 amino acids. PTH exerts its action via cell-surface parathyroid hormone receptors, present in bone, kidney and nerve tissue. PTH has a variety of critical physiological functions that include its central role in modulating serum calcium and phosphate levels within tightly regulated levels, regulating renal calcium and phosphate excretion, activating vitamin D, and maintaining normal bone turnover.

Read more about Parathyroid hormone

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