86 out of 93
DOC for prevention of postmenopausal osteoporosis is: (AIIMS Nov 10)
Ans. A Raloxifene
(BG Katzung, Basic & Clinical Pharmacology’ 11th Edition’ 2010; pp-766)
- Raloxifen is a SERM having partial agonistic activity (agonist-antagonist) and is used for prevention of postmenopausal osteoporosis.
- Importantly, it has similar activity at bone and lipids but does not have similar action on the endometrium. That means, unlike tamoxifen it does not cause endometrial hyperplasia.
- Although, subjected to high first pass metabolism, the drug does have a volume of distribution. Therefore, the drug can be taken once a day.
- It is commonly regarded to be the drug of choice for prevention of postmenopausal osteoporosis.
- The drug is effective in reducing spine fractures but not hip fractures unlike bisphosphonates and teriparatide that can protect against both.
- Calcium or vitamin D could be added if the daily intake seems inadequate. The drug also reduces risk of breast cancer.
- Hot flashes and leg cramps are common. Risk of thromboembolic event is the major drawback. Calcitonin a calcinuric hormone librated by parafollicular C cells is also effective in postmenopausal osteoporosis.
- This drug is also effective in reducing risk of spine fractures but not in hip fractures. Bisphosphonates are potent inhibitors of bone resorption.
- These reduce fracture risk in spine, hip and other locations. Strontium increases new bone formation. Denosumab is an antibody to RANKL antibody and is interfere with osteoclast.
- Toremifen is SERM used for advanced breast cancer and is being evaluated for cancer if prostate. The drug has similar pharmacological spectrum as tamoxifen.
- Clomiphene is an older partial agonist partial agonist, a weak estrogen that also acts as a competitive inhibitor of endogenous estrogens.
- It is considered to be the drug of choice for inducing ovulation and is also used in azoospermia. Half-life of drug is 7 days and is eliminated in urine.