MNU I Drugs

Question 1

bisphosphonate - Etidronate

Answer 1

Osteoporosis
Paget’s disease of the bone
Osteolytic Malignancy
- Incorpororates into ATP and promotes osteoclast apoptosis
- only 1-2% bioavailability orally
- Must be taken on an empty stomach with no food for 2 hours afterwards
- IV zoledronate bypasses first-pass effect so only needs to be given once yearly

Question 2

Bisphosphonate - Alendronate, ibandronate, zoledronate

Answer 2

Osteoporosis
Paget’s disease of the bone
Osteolytic Malignancy
- Inhibits enzyme that farnesylates proteins in osteoclasts, leads to impair cell trafficking and function
- only 1-2% bioavailability orally
- Must be taken on an empty stomach with no food for 2 hours afterwards
- IV zoledronate bypasses first-pass effect so only needs to be given once yearly

Question 3

Parathyroid Hormone Analog ex. Teriparatide (Forteo)

Answer 3

Some forms of Osteoporosis

• Low doses paradoxically favour osteoblast activity (good)
• High doses favour bone resorption (bad)
• Increased risk of osteosarcome - not for patients with bone malignancy or children
• very short half-life so must be given by injection daily

Question 4

Thyroid Hormone Analogs - Levothyroxine (synthoid)

Answer 4

Replacement therapy Hypothyroidism
Mimics T4
Longer half-life
Side effects: Elevated BMR, Poor thermogenesis, Weight loss, Tremors, Tachycardia
Contraindications: give 1.5 dose in pregnancy to prevent cognitive deficits in fetus
Increase dose v. slowly in CVD or elderly

Question 5

Thyroid Hormone Analog - Liothyronine (cytomel)

Answer 5

Mimics T3
Is taken then withdrawn prior to thyroid ablation with i-131, shorter half-life = shorter withdrawal time
Side effects: Elevated BMR, Poor thermogenesis, Weight loss, Tremors, Tachycardia
Contraindications: give 1.5 dose in pregnancy to prevent cognitive deficits in fetus
Increase dose v. slowly in CVD or elderly

Question 6

Thonamide: Propylthiouracil

Answer 6

Hyperthyroidism (temporary)
- only given in first trimester of pregnancy
- inhibits peroxidase and subsequent oxidation of iodide = no iodine fixation onto thyroglobulin
Side effects - agranulocytosis, drug-induced goitre, Rash, arthralgia, edema
Not given except for in 1st trimester, causes hepatotoxicity

Question 7

Thionamide: Methimazole

Answer 7

Hyperthyroidism (temporary)
- inhibits peroxidase and subsequent oxidation of iodide = no iodine fixation onto thyroglobulin
Side effects - agranulocytosis, drug-induced goitre, Rash, arthralgia, edema
Not given e in 1st trimester, causes risk of cutis aplasia (scalp malformation)

Question 8

Radioactive Iodine I-131

Answer 8

Hyperthyroidism (grave’s, thyrotoxicosis), Thyroid Cancer
Targeted destruction of thyroid cells via B-particle emission
possible salivary gland toxicity
not while breastfeeding