Agents that affect Calcium/Bone Homeostasis Flashcards
what are the conditions that can lead ot hypercalcmemia?
- hyperparathyroidism
- parathyroid adenoma / carcinoma / hyperplasia
- Cancers +/- bone metastasis
- Hypervitaminosis (Vit D)?
what are the conditions that can lead to hypocalcemia?
- Hypoparathyroidism (autoimmune, psuedohypothyroidism)
- insufficient gut Ca++ absorption:
- Vitamin D deficiency (rickets, osteomalacia)
- CKD? but its secondary hyperthyroidism?
- other reason for alabsorption - Ca++ not absorbed in gut
- Vitamin D deficiency (rickets, osteomalacia)
what is osteoporosis?
how does it present?
a generalized loss of bone mass and strength from excessive bone resorbption
increased risk of fractures
what is pagets disease of the bone?
how does it present?
localized increases in bone turnover due to excessive bone resorption, followed by replacement with structurally abnormal bone
presentation: skeletal deformities (misshapen bones) + fractures

what is the role of
- estrogen
- calicitonin
- PTH
in bone metabolism?
-
inhibits osteoclast activity, PREVENTING bone resorption:
-
estrogen:
- (this is why estrogen loss in women during age weakens bones)
- calticonin
-
estrogen:
-
promotes osteoclast activity, INDUCING bone resorption
- PTH
what two major classes of drugs are used to treat osteoporosis?
- anti-resorptive agents
- anabolic agents
what are the anti-resorbtive agents used to treat osteoporosis?
in what situations are they used?
what do they all have in common?
- bisphophonates - 1st line
- denosumab - 1st line
- raloxifene - 1st in in post-menopausal
- calcitonin - in post-menopausal (not first line)
all suppress osteoclast activity
what are the anabolic hormones used to treat osteoporosis?
- teriparatide (PTH analog)
- sclerostin inhibitor
bisphosphonates
incudes what drugs?
“dronate and dronic”
- - dronate: alendronate, risedronate, ibandronate, pamidronate
- zoledronic acid
bisophosphonate MOA
anti-resorptive agent
-
inhibit bone resorbtion by suppressing osteoclasts
- permanently incorporate into bone* - have effects post discontuation
- induce osteocast apoptosis
- disrupt osteoclast activity
bisphosphonates - clinical uses
- osteoporosis - 1st line tx
- Paget’s disease
- bone metastasis / hypercalcemia of malignancy
- reduction of bone fracture risk
bisphosphonates AEs / CIs
- AEs
- esophageal & gastric irratitation / ulcers
-
hypocalcemia & related consequences:
- jaw osteonecrosis (ONJ)
- atypical femur fracturefs (AFF)
- C/I:
- esophgeal disorders / peptic ulcers
- severe hypocalcemia (renal disease)
bisphosphonates - pharmokinetics
poor oral absorption that is inhibited by food.
pt must take in FASTED STATE (water only)
alendronate
what kind of drug?
available in what forms?
bisphosphonate
- oral: daily, weekly
risendonrate
what kind of drugs?
available in what forms?
bisphosphonate
- oral: daily, weekly
ibandrate
what kind of drug?
available in what forms?
bisphosphonate
- oral: daily, monthly
- IV: quarterly
pamidronate
what kind of drug?
available in what forms?
bisphosphonate
- IV only: monthly injection
zoldronic acid
what kind of drug?
available in what forms?
bisphosphonate
- IV only: given yearly or (for osteoporosis prevention) once every 2 years
how should a patient be instructed to take an oral bisphosphonate?
- dronates
- take it fasting (water only) - bisphosphonates have poor oral bioavability
- sit upright for 30 min after taking - prevents formation of gastric & esophageal ulcers
denosumab
what kind of drug?
MOA?
- an anti-resorptive drug (thus, suppresses osteoclasts)
- MOA: is an RANKL-antibody that binds RANK-L, inhibiting its binding with RANK receptors on osteoclasts. this inhibits osteoclast activation
denosumab - clinical uses
= RANK-L inhibitor
- osteoporosis - 1st choice - used as an alternative to bisphosphonates
- hypercalcemic malignancy
(similar to bisphosphonates)
denosumab
is available in what form?
- injections (subcutucaneous) - given every 6 mos
denosumab- AEs / CIs?
- AE
-
hypocalcemia & related effects
- jaw osteonecrosis (ONJ)
- atypical femur fractures (AFF)
-
hypocalcemia & related effects
- CI
- hypocalcemia
(similar to bisphosphonates)
which osteoporosis drug can cause an increase in bone mass density (BMD) that persists beyond discontinuation of therapy?
why?
bisphosphonates (dronates & zoldedronic acid)
this is because they permanently incorporate themselves into bone
raloxifene
- what kind of drug?
- MOA?
- is an antiresorptive drug
- MOA: specifically a SERP: selective estrogen receptor modulator
-
raloxifene is an agonist in some tissue but an antagonist in others
- agonism in certain tissues (bone) serves to stimulate estrogen, thus inhibiting osteoclasts activity
- antagonism in certain tissues (breast, endometrium) serves to inhibit estrogen, preventing cancer development
-
raloxifene is an agonist in some tissue but an antagonist in others
- MOA: specifically a SERP: selective estrogen receptor modulator
raloxifene -clinical uses?
= SERM (selective estrogen receptor modulator)
- to prevent/treat osteoporosis in postmenopausal females
raloxefine - AEs / CIs?
= SERM (selective estrogen receptor modifiers)
- AEs:
- leg - arthralgia /cramps / muscle spasms
- increases risk of thromboembolism
- hot flashes
- CI:
- in pts with hx/current venous thromboembolitic disorders*
compare and contrast bisphosphonates to RANK-L inhibitors
(what are the drug names in each of these classes?)
bisphosphonates: - dromate (oral/IV), zoledronic acid (IV only)
RANK-L inhibitor: denosumab (injection)
-
both:
- are anti-resorptive drugs
- treat
- osteoporosis (1st line)
- bone metastasis / hypercalcemia malignancy
- AEs
- hypocalcemia (+ ONJ, AFF)
- C/I in: severe hypocalcemia
-
only bisphosphonates:
- increase BMD after drug discontinuation
- can treat: Paget’s disease
- can cause: esophageal / gastric ulcers irritation
- C/I in: hx of esophgeal / gastric disorders
- must taken while fasting & while pt is upright for 30 min*
estrogens
- MOA
- have what clinical uses?
- AEs /CIs?
- MOA: antiresorptive via osteoclast supression
- uses:
- to treat osteoporosis in postmenopausal women - NOT first choice
- to relief other postmenopausal symptoms
- AEs:
- endometrial / breast carcinoma
- venous thrombombolism
calcitonin
- what kind of “drug”?
- MOA?
- clinical uses?
- available in what forms?
- AEs / CI?
- grouped with resorptive drugs
- MOA:
- secreted by thyroid in response to hypercalcemia
- lowers both Ca and PO4
- secreted by thyroid in response to hypercalcemia
- clinical uses:
- postmenopausal osteoporosis - not first line
- paget’s disease - not 1st line
- hypercalcemia
- formulations:
- human calcitonin
- “salmon” calcitonin = intranasal / sc / im; longer half life
- AEs:
- hypersensitivity / flushing
- nausea / GI cramps
what are the AEs of calcitonin?
- hypersensitivity / flushing
- nausea / GI cramps
what drugs are specifically indicated for postemenopausal osteoporosis? how are they different?
- estrogen & raloxafine (SERM) -
-
both: are risk factors for a venous thromboembolism (stroke)
- raloxifene - 1st choice
-
estrogen - NOT first choice
- is also a factor for breast/emdometrial cancer
-
both: are risk factors for a venous thromboembolism (stroke)
calcitonin also used for postemenopausal osteoporosis (amongst other things). not 1st choice
which drugs are used to treat Paget’s disease?
which one is first choice?
- bisphosphonates (dromate, zoledronic acid)- 1st choice
- calcitonin - NOT first choice
PTH
- has what key physiological affects?
- how does it mediate these effects?
PTH acts at
-
bone:
- inc Ca reabsorption (via osteoclast activation)
- inc PO4 reabsorption (released along w/ Ca)
-
kidney:
- inc Ca reabsorption
- dec PO4 reabsorption
net effect: raise plasma calcium and lower plasma phosphate
teriparatide
- what kind of drug?
- MOA?
-
an anabolic hormone
- MOA: is a PTH analog - that, when administered intermittently, induces osteoclast activity (by inducing RANK-L secretion by osteoblasts) that is immediately followed by bone deposition (by osteoblasts) - having the net effect of bone building (“anabolic effect”)
teriparatide - clinical uses
treatment of osteoporosis in pts with a high fracture risk who have failed the antiresorptive agents (bisophosphonates, denosumab, reloxifene, calcitonin)
teriparatide - PK
- dosing is: intermittent (once daily) - this timing is imperative for a net anabolic effect.
- continuous/high circulating of PTH = bone resorbption > bone formation
teriparatide - AEs/CIs
- AEs
- it teraparatide is givin with continuous administration then circulating PTH levels become too high and reabsorptive effets > anabolic effects, and related AEs present:
- hypercalcemia / hyperuricemia
- dizziness / fatigue
- cramps / arthralgia
- it teraparatide is givin with continuous administration then circulating PTH levels become too high and reabsorptive effets > anabolic effects, and related AEs present:
- CI:
- hypercalcemia / hyperparathyroidism
- Pagets
vitamin D preparations come in what forms?
oral supplements
- ergocalciferol
- cholecalciferol
- calitriol
Vitamin D supplements
clinical uses?
- rickets / osteomalacia
- hypocalcemia (d/t hypoparathyroidism)
- renal osteodystrophy d/t CDK)
- osteoporosis
which Vitamin D supplement is especially useful in hypocalcemia due to chonic kidney disease?
calcitriol
is the active form of Vit D, which is useful in patients with CDK, form whom the final step in vitamin D synthesis is impaired
which Vitamin D analog can be used to treat psoriasis?
calcipotriene
Vit D drug drug interactions
- phenobarticals/phenytoin - inc metabolism
- mineral oil/resins - impair absorption
Vit D AEs?
- hypercalcemia / calciuria
- hyperphosphatemia
Vitamin D C/I
- hypercalcemia
- hyperparathyroidism
- pregnancy*
- sarcoidosis
contrst PK of ergocalciferol (D2) vs cholecalciferol (D3)
cholecalciferol = more potent & longer half life (6 weeks > 1 week)
calcium preparations
include what drugs?
various calcium carbonates: calium carbonate, calcium gluconate, ect
calcium supplements (preparations)
- clinical uses
- formulations
- PK (& drug-drug interactions)
- AE
Ca-carbonate, Ca-gluconate
- clinical uses: given w/ Vit D for:
-
prevention of osteoporosis:
- oral supplement + dietary Ca + Vit D
- hypocalcemia
- oral / IV supplement + Vit D
-
prevention of osteoporosis:
- formulations: IV & oral
- PK:
- requires acidic environment for dissolution
- drug-drug: absorption reduced by anti-acids & laxatives
- AEs:
- constipations / GI upset
- kidney stone risk*
calcimimetics
- MOA
- clinical uses
- MOA: is a Ca++ analog that binds parathyroid cells on the parathyroid gland to decrease synthesis of PTH
- clinical uses:
- primary hyperparathyroidism in pts who can’t undergo surgery
- secondary hyperparathyroidism in chronic renal dz
- parathyroid carcinoma
romosozumab
- what kind of drug?
- MOA?
- clinical uses?
- AE?
- anabolic drug: scerlostin inhibitor
- MOA: increases bone formation for 12 months
- clinical uses: osteoporosis in _post meno-pausal female_s at high bone fracture risk
- AE
- cardiovascular: MI / stroke
what drugs can be used to treat osteoporosis in post-menopausal women?
what are their individual AEs?
- estrogen - thromboembolism / breast & uterine cancer
- raloxifene (SERM) - thromboembolism
- calcitonin - hypersensitivity / flushing
- romosuzumab (clerostin inhibitor) - MI / stroke / CV death