Looking for input on 2nd opinion after 3 years of Alendronate

I could not tolerate Forteo, which delayed my osteoporosis treatment for a few years, until Tymlos became available. On Tymlos, my spine went from -3.7 to -2.5 and my hip from -3.3 to -2.9.

I plan on asking my doctor about the dosage differences between Forteo and Tymlos. Forteo is a parathyroid hormone and Tymlos is a parathyroid protein, so I wonder if Forteo's action is more direct and therefore the dosage is lower. Does anyone have info on this? Of course, the Tymlos dose is adjustable but some may take 1/2 to mimic Forteo dosage and it would be good to know if that is a valid choice.

Teriparatide (T) results in prolonged (longer) signaling of the cAMP pathway while Abaloparatide (A) is transient (shorter). The research paper linked below explains that this is related to how each bind to the parathyroid hormone type 1 receptor which has two conformations (R0 and RG). T has a greater affinity to the R0 conformation which results in prolonged signaling while A has a greater affinity to the RG conformation which results in shorter signaling.

The paper also explains that this accounts for the lower risk of hypercalcemia and less bone resorption signaling seen with A.
https://pmc.ncbi.nlm.nih.gov/articles/PMC9586930/

I am in the San Francisco Bay Area and noted that folks here mentioned going to the Stanford Osteoporosis and Metabolic Bone Diseases Clinic so I contacted them about how to become a patient. I had to have my doctor submit a referral. Once that was done and they reviewed my medical records, they agreed to see me. I am so glad they did and I am really looking forward to my appointment.

@oopsiedaisy thanks. I have read that study a couple of times, and it was posted very recently by @gently. It still doesn't answer my question about comparing dosing. The two meds are different in some ways yet posts tend to say that Forteo is lower dose. I am going to ask my doctor if dosage comparisons are apples to apples or apples to orange!

I have done both Tymlos and teriparatide (generic Forteo) after five years of alendronate. I was referred to a rheumatologist after fracturing on Alendronate. My spinal t-scores were never in the osteoporotic range.

I was on Tymlos for 4.5 months then switched to Forteo as my commercial insurance would not longer cover Tymlos.

I much prefer the Forteo as I have fewer side effects. I thought I was tolerating the Tymlos ok but now that I am on Forteo, it’s clear that it was impacting me in several ways more so than Forteo.

I haven’t been on either for long enough to see an outcome (6 months) but it’s been 13 months and I haven’t fractured again.

Is it possible for you to get another opinion on your long term treatment? I am 63 and also active and realize now that I really need the best plan for me for the rest of my life. I plan to have a discussion with my rheumatologist about that soon as she has not discussed what comes next at all. I also have an appointment with an endocrinologist specializing in osteoporosis in April to discuss the same. My insurance company allows me to see any specialist I want as long as my PCP submits a referral to the specialist.

I’d still see someone even if insurance wouldn’t pay as this is too important for me to get wrong. I am still working and planning an active retirement and want to ensure I am as healthy as possible and ensuring my osteoporosis is treated appropriately for me is critical.

Wishing you all the best and hoping you can find a doctor to work with you on this,

patwerthman, I'm curious about the source of your virtual recommendation.
I don't have experience with the medications except Forteo. Bisphosphonates are now recommended for three to five years. Because you haven't gained density with alendronate over the last year, it's a great time for the switch. I have a preference for Forteo because it is a lower dose of medication than Tymlos and because I'm not content with the mechanism of action of Evenity.
There isn't a way of determining how much bone loss aledronate has prevented. You probably have and will maintain fracture protection for several years from taking it, even as your bmd remains low.
In your situation, I would take Forteo or Tymlos for two years. Prior bisphosphonate use is said to delay the effectiveness of either medication, studies have shown that there isn't significant difference after one and two years of use. There isn't actual rebound with either Tymlos or Forteo. There is gradual bone loss after you quit using either drug.
I'm starting a third year with Forteo. At 16 months the T score changes in the spine were from -3.3 to -2.8; femoral neck -3.0 to -2.9 ; right hip loss from -2.4 to -2.5. The trabecular structure improved reducing fracture risk in the spine and the hips.
The endocrinology response surprises me.

@gently I didn't realize you could use Forteo past two years. Also thought its effectiveness waned the longer you use it. You say you are starting a 3rd year; if you know of a study documenting results at that point (or further along), could you let me know?

@windyshores So did you go from Tymlos to Forteo? Or Tymlos to Evenity to Forteo? After seeing Dr. Leder's lecture, it's clear that sequencing may be an important consideration where effectiveness is concerned.

Thank you once again for sharing your experiences and the research you've done. You've been incredibly helpful.