Week 3 - Drugs and Treatments Flashcards
What three therapeutic options exist for Grave’s disease?
- Antithyroid Drugs
- Surgery (near total thyroidectomy)
- Radioactive Iodine
What are two antithyroid drugs?
Methimazole & Propylthiouracil (PTU)
PTU is preferred in the first trimester of pregnancy.
What are some side effects of using radioactive iodine treatment for Grave’s disease?
- Hypothyroidism if the dose is high enough.
- A low incidence of thyroid & small bowel cancer.
- Possible worsening of ophthalmopathy.
What is amiodarone?
An antiarrhythmic drug which is also an exogenous cause of hypothyroidism; it is 37% iodine.
What are the four classes of drugs used to treat dyslipidemia?
- Statins / HMG-CoA Reductase Inhibitors
- Bile Acid / Cholesterol Absorption Inhibitors
- Fibrates
- Niacin
What other substances may be used to treat dyslipidemia?
- Fish Oils
- Herbal Therapies / Dietary Supplements (garlic, oat bran, flax seed oil . . .)
How do statins / HMG-CoA Reductase Inhibitors work?
They inhibit the rate-limiting step in cholesterol synthesis. Cells compensate by increasing the number of LDL receptors resulting in increased LDL plasma clearance.
What are the side effects, contraindications, and precautions for statins / HMG-CoA Reductase Inhibitors?
SE: Myopathy, increased liver enzymes.
CI: Severe liver disease.
PC: Avoid with certain drugs (metabolism issues).
How do Bile Acid / Cholesterol Absorption Inhibitors (Ezetimibe)(Resins) work?
Bind and inhibit reabsorption of bile acids leading to increased LDL receptor expression by the liver and increased LDL plasma clearance.
Blocks cholesterol absorption by the intestines.
How much can Bile Acid / Cholesterol Absorption Inhibitors lower cholesterol? How much will they lower cholesterol if used synergistically with Statins?
By itself: 18-25%
Synergistically with statins: upto 40%
What are the side effects, contraindications, and precautions for Bile Acid / Cholesterol Absorption Inhibitors?
SE: May increase triglycerides, constipation/stomach or bowel discomfort, decreased absorption of other drugs.
CI: Elevated triglycerides (> 4 mmol/L).
How do Fibrates work?
They increase fatty acid oxidation, HDL production, and increase lipoprotein lipase activity.
What are the side effects, contraindications, and precautions for Fibrates?
SE: Myopathy, dyspepsia (indigestion), gallstones.
CI: Severe kidney or lived disease.
PC: Myopathy is worsened if used with statins.
How does Niacin work?
It inhibits mobilization of fatty acids from peripheral tissues, reduces VLDL production, and reduces HDL catabolism.
What are the side effects, contraindications, and precautions for Niacin?
SE: Flushing, itching, hepatotoxicity, hyperglycemia, hyperuricemia, and upper GI distress.
CI: Liver disease, gout, peptic ulcers; elevated blood sugar is a relative, but not absolute, CI.
What do fish oils do?
Inhibit triglyceride synthesis and VLDL secretion. May raise HDL upto 5% but has little effect on LDL.
What much may fish oils lower triglycerides by?
30%
Garlic, Rhubarb, and Red-yeast fermented rice contain ______ and lower cholesterol.
statins
What is/are the drug(s) of choice for hypercholesterolemia?
Statins or Bile Acid Binding Resins.
Niacin can also be used.
What is/are the drug(s) of choice for combined hyperlipidemia?
Statin if TG < 3-4.
Fibrates or Niacin if TG are higher.
What is/are the drug(s) of choice for high triglycerides with low HDL?
Niacin or Fibrates
What is/are the drug(s) of choice for isolated low HDL?
Niacin of Fibrates; if unresponsive Statins to lower LDL.
What is/are the treatment(s) of choice for severe hypercholesterolemia?
LDL apheresis and liver transplantation.
How does lithium affect the thyroid?
Lithium is used to treat bipolar disorder but also inhibits thyroid hormone synthesis. Hypothyroidism is also common with lithium use; it can be treated with thyroxine replacement.
How does interferon affect the thyroid?
Interferon is used to treat hepatitis C and other disorders. In 7% of cases it also causes thyroid dysfunction, usually in the form of hypothyroidism.
