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Everyone knows what Erdafitinib does and what its main side effects are, but these are the most serious ones.
1. vision problems
2. Hyperphosphatemia and fatigue
3. problems with digestion and weight loss
I’ll explain how to mitigate each of these
vision loss
This is the one everybody knows about, so I’ll start with it. Erdafitinib works by inhibiting fgfr. fgfr helps maintain the retinal pigment epithelium (RPE) cells in the eyes. These RPE cells are responsible for pumping liquid out of the retina. When fgfr is inhibited it can lead to Central Serous Retinopathy (CSR) which is when fluid begins to leak and accumulate under the retina. Also, Erdafitinib can harm the cells in the cornea which causes reduced tear production and dry eyes.
Dealing with dry eyes is simple; just use eye drops you can get from cvs or amazon. CSR is more serious. The effects of CSR generally go away after you stop taking Erdafitinib, but while using it you need to be extremely careful or you could get permanent vision loss. If your vision gets significantly worse or if you see wavy lines and dark spots then you should lower your dose until it gets better. You can possibly slow the onset of CSR by lowering your stress and blood pressure but don’t count on it. One other possible treatment is Dorzolamide eye drops. Dorzolamide is a carbonic anhydrase inhibitor. The carbonic anhydrase enzyme is responsible for converting CO2 and water into bicarbonate and hydrogen ions. These two ions drive the sodium-hydrogen exchange responsible for pumping fluid into the eye. This means that by inhibiting carbonic anhydrase we can possibly reduce the amount of fluid that accumulates under the retinas while on Erdafitinib. Dorzolamide has its own side effects to worry about but I’m not going to go over them. Do your own research.
Hyperphosphatemia
This one is responsible for many of the other side effects reported while on Erdafitinib such as fatigue, coarse hair, brittle nails, and dry skin; this is why I’m not going over them separately. Hyperphosphatemia is simply the term for elevated phosphate levels in the blood. Erdafitinib causes this by hindering the kidneys’ ability to filter out excess phosphate. By itself, Hyperphosphatemia doesn’t do much, but it leads to hypocalcemia as the excess phosphate binds to the calcium. hypocalcemia is the real driver of the side effects I mentioned.
You absolutely need to monitor your calcium and phosphate levels while on this drug. Hyperphosphatemia can be partially treated by reducing the amount of phosphorus in your diet to 800-1000 mg per day. However, you also need to be taking calcium supplements such as calcium acetate or calcium carbonate. These supplements will bind to the phosphate and prevent hypocalcemia, but you need to monitor your calcium levels closely like I said because you could end up with hypercalcemia which is too much calcium.
I’m going to touch on fatigue a bit because of how important it is to me. The fatigue from Erdafitinib is caused by Hyperphosphatemia like I said but it also has a few other causes. In about 30% of patients Erdafitinib reduces the amount of red blood cells in the body. This hinders the transportation of oxygen to the cells. There isn’t much you can do about this besides taking iron supplements. You could take erythropoiesis-stimulating-agents which help your body produce more red blood cells, but if it gets to that point you’re just killing yourself for a few cm and scoliosis.
problems with digestion and weight loss
Erdafitinib damages the lining of the gastrointestinal tract. This affects the absorption of water and vitamins which can lead to diarrhea. erda also causes altered taste perception. This combined with the GI irritation causes reduced appetite and weight loss.
This really isn’t that complicated just don’t eat foods that irritate your gut and as for the reduced appetite just force the food down.
And that’s it. Don’t kill yourselves. If you have any notes or if you think I made a mistake let me know because I made this partially for myself.
1. vision problems
2. Hyperphosphatemia and fatigue
3. problems with digestion and weight loss
I’ll explain how to mitigate each of these
vision loss
This is the one everybody knows about, so I’ll start with it. Erdafitinib works by inhibiting fgfr. fgfr helps maintain the retinal pigment epithelium (RPE) cells in the eyes. These RPE cells are responsible for pumping liquid out of the retina. When fgfr is inhibited it can lead to Central Serous Retinopathy (CSR) which is when fluid begins to leak and accumulate under the retina. Also, Erdafitinib can harm the cells in the cornea which causes reduced tear production and dry eyes.
Dealing with dry eyes is simple; just use eye drops you can get from cvs or amazon. CSR is more serious. The effects of CSR generally go away after you stop taking Erdafitinib, but while using it you need to be extremely careful or you could get permanent vision loss. If your vision gets significantly worse or if you see wavy lines and dark spots then you should lower your dose until it gets better. You can possibly slow the onset of CSR by lowering your stress and blood pressure but don’t count on it. One other possible treatment is Dorzolamide eye drops. Dorzolamide is a carbonic anhydrase inhibitor. The carbonic anhydrase enzyme is responsible for converting CO2 and water into bicarbonate and hydrogen ions. These two ions drive the sodium-hydrogen exchange responsible for pumping fluid into the eye. This means that by inhibiting carbonic anhydrase we can possibly reduce the amount of fluid that accumulates under the retinas while on Erdafitinib. Dorzolamide has its own side effects to worry about but I’m not going to go over them. Do your own research.
Hyperphosphatemia
This one is responsible for many of the other side effects reported while on Erdafitinib such as fatigue, coarse hair, brittle nails, and dry skin; this is why I’m not going over them separately. Hyperphosphatemia is simply the term for elevated phosphate levels in the blood. Erdafitinib causes this by hindering the kidneys’ ability to filter out excess phosphate. By itself, Hyperphosphatemia doesn’t do much, but it leads to hypocalcemia as the excess phosphate binds to the calcium. hypocalcemia is the real driver of the side effects I mentioned.
You absolutely need to monitor your calcium and phosphate levels while on this drug. Hyperphosphatemia can be partially treated by reducing the amount of phosphorus in your diet to 800-1000 mg per day. However, you also need to be taking calcium supplements such as calcium acetate or calcium carbonate. These supplements will bind to the phosphate and prevent hypocalcemia, but you need to monitor your calcium levels closely like I said because you could end up with hypercalcemia which is too much calcium.
I’m going to touch on fatigue a bit because of how important it is to me. The fatigue from Erdafitinib is caused by Hyperphosphatemia like I said but it also has a few other causes. In about 30% of patients Erdafitinib reduces the amount of red blood cells in the body. This hinders the transportation of oxygen to the cells. There isn’t much you can do about this besides taking iron supplements. You could take erythropoiesis-stimulating-agents which help your body produce more red blood cells, but if it gets to that point you’re just killing yourself for a few cm and scoliosis.
problems with digestion and weight loss
Erdafitinib damages the lining of the gastrointestinal tract. This affects the absorption of water and vitamins which can lead to diarrhea. erda also causes altered taste perception. This combined with the GI irritation causes reduced appetite and weight loss.
This really isn’t that complicated just don’t eat foods that irritate your gut and as for the reduced appetite just force the food down.
And that’s it. Don’t kill yourselves. If you have any notes or if you think I made a mistake let me know because I made this partially for myself.
