Sketchy Pharm: Teriparatide, Vitamin D, Cinacalcet, Sevelamer

Question 1

Osteoclasts release what two factors from bone?

Answer 1

Phosphate and calcium (like the P-shaped shells and the bones being unearthed by the CLASsmates)

Question 2

High _____________ inhibits PTH.

Answer 2

calcium

Think of the stack of bones preventing the PHd from visiting the excavation site.

Question 3

How does PTH induce calcium resorption from the bone?

Answer 3

It stimulates osteoblasts to make RANK-ligand which then activates osteoclasts (like the PHd convincing the osteo-builder to give his cRANK to the CLASsmate).

Question 4

What stimulates the maturation of osteoblasts?

Answer 4

PTH

Think of the PHd teaching the osteo-builders how to reconstruct the fossil.

Question 5

What does PTH do at the kidney?

Answer 5

• PTH stimulates the resorption of calcium from the DCT in exchange for excreted phosphate (like the PHd picking up fossils from the kidney-shaped crater and dropping P shells).
• PTH also stimulates the 1-hydroxylation of vitamin D (like the Calcitron robot being assembled –he’s got a 1-shaped antenna).

Question 6

Describe teriparatide.

Answer 6

• Teriparatide is a synthetic PTH that primarily stimulates the formation of bone (like the TA helping the PHd teach the osteo-builders how to reconstruct the skeleton).
• It also helps increase calcium resorption from the kidney (like the TA in the kidney hole).
• Lastly, it helps stimulate vitamin D formation in the kidney (TA helping assemble robot).

Question 7

Teriparatide is used to treat ______________.

Answer 7

those with osteoporosis (like the TA’s new, intact piece of chalk)

Question 8

D3 is obtained from ________________.

Answer 8

dairy and the sun (think of the cow pulling the solar panels that are charging the D3 batteries)

Question 9

D3 is also called ____________.

Answer 9

cholecalciferol (SOLecalciferol)

Question 10

Plants have what kind of vitamin D?

Answer 10

Ergocalciferol (like the EaRth-friendly D2 batteries)

Question 11

What happens first, hydroxylation in the liver or kidney?

Answer 11

Liver

The D3 battery is first put in the liver-shaped wheelbarrow before being carted to the kidney hole.

Question 12

Compare the effects of PTH and D3 at the kidney.

Answer 12

• PTH: only causes resorption of calcium (PHd is only getting bones)
• D3: causes absorption of both calcium and phosphate (like the robot holding bones in one hand and shells in the other)

Question 13

In addition to hypercalcemia, _____________ also inhibits the production of PTH.

Answer 13

vitamin D (like the robot bringing more bones to the overwhelmed PHd)

Question 14

Vitamin D stimulates _____________ in osteoblasts.

Answer 14

RANK production (like the robot helping deliver cranks)

However, since vitamin D also stimulates osteoblasts it leads to overall bone formation.

Question 15

Calcitriol (1,25-dihydroxy vitamin D) is used to treat what bone disorders?

Answer 15

rickets, osteomalacia, and renal osteodystrophy; it’s important to give calcitriol to those with renal failure, because they won’t be able to do the second hydroxylation necessary to make vitamin D

Question 16

Calcitriol is used to treat what skin disorder?

Answer 16

Psoriasis (like the thick joint pads worn by the construction worker)

Question 17

Patients who’ve had what surgery might need calcitriol afterward?

Answer 17

Thyroidectomy –the parathyroids can be damaged or removed in this procedure and lead to hypocalcemia (like the guy with the undone bowtie and the tremors being helped by the robot)

Question 18

Teriparatide and vitamin D can both cause what side effect?

Answer 18

Hypercalcemia (like the robot and TA raising the ice cream)

Question 19

How does cinacalcet work?

Answer 19

It allosterically activates the calcium sensors in the parathyroid gland and decreases the production of PTH. This is useful in the treatment of hyperparathyroidism.

(Think of the guy at the conveyor belt with the CALculator telling the PHd that there is too much bone.)

Question 20

What does sevelamer do?

Answer 20

It binds phosphate in the GI tract and prevents its absorption – useful in the management of CKD-associated hyperphosphatemia (like the SeVELamER ShoVELER scooping the P shells in the truck and preventing the robot from grabbing too many).