@brendammc, Forteo is an analog the first 34 DNA segments of parathyroid hormone. Tymlos is a synthetic analog of the first 34 DNA segments of parathyroid hormone related protein. While Forteo is considered biologic in Europe because it is generated from biologic material before manipulation, Tymlos is entirely synthetic.
Tymlos inserts changes in the last 12 segments of the DNA. The processes involved with each are fascinating, but you are probably asking the difference in effect.
Abaloparatide works by binding to and activating PTHR1. The same binding site as Forteo. This binding site has two receptors RO and RG. Tymlos has more affinity to the RG receptor.
Binding to this receptor causes a more transient effect which increases bone building and decreases bone absorption than more than Forteo. Though, Forteo is seen to have more bone building capacity in the spine and Tymlos better in hips.
Tymlos is in an 80mcg dose, Forteo 20. Tymlos is usually only 36% absorbed, Forteo 95%.
Tymlos is less likely to cause hypercalcemia.
Tymlos contains the preservative phenol. Some people are allergic to the phenol. The preservative in Forteo is metacresol. While metacresol protects against microbial growth, it doesn't protect against the breakdown of the drug itself which is highly sensitive to heat. As such Forteo must be refrigerated.
Evidence indicates that the incidents of side effects are greater with Tymlos.
Tymlos isn't available in Canada. In 2021 a marketing agreement was signed, but nothing followed.