Forteo: some details.
**Note that Forteo is not FDA approved for hypoparathyroidism**
The Forteo pen is set to give a fixed dose of 20 microgram, which comes in a volume of 80 microliters (this is the dose that patients for osteoporosis need).
For hypoparathyroidism, variable dosing is necessary and is achieved by drawing Forteo from the cartridge with an insulin syringe and needle (which is not FDA approved).
Insulin is dosed by “units”; therefore, insulin syringes are marked with “units.”
- 1 unit = 10 microliters.
- 10 microliters of Forteo = 2.5 microgram of Forteo = 1 unit
- 80 microliters of Forteo = 20 microgram of Forteo = 8 units
When used for hypoparathyroidism (off label), Forteo should be given at least twice daily (some might need three injections per day, roughly 8 hours apart). The more frequently Forteo is administered, the less Forteo per day is needed for most patients.
On a molar basis, 1 microgram of Forteo corresponds to about 2.3 micrograms of Natpara.
A person who was on 50 micrograms of Natpara, might get away with 10 micrograms of Forteo (4 units) twice daily. Frequent blood tests are needed to adjust the dose of Forteo (and/or calcium/calcitriol).
Forteo’s website contains a warning: Do not transfer the medicine from the FORTEO delivery device to a syringe. This can result in taking the wrong dose of FORTEO.