Currently used oral hypoglycemic biguanides include the following EXCEPT:

Correct Answer: A

Rationale: The correct answer is A, Repaglinide (Prandin), as it is not a biguanide but a meglitinide used for managing type 2 diabetes by stimulating insulin release. Metformin is a biguanide commonly used as a first-line treatment for type 2 diabetes due to its efficacy and safety profile. Phenformin is a biguanide that was withdrawn from the market due to its association with lactic acidosis. Glipizide is a sulfonylurea, not a biguanide, and works by stimulating insulin release from the pancreas. Therefore, A is the correct answer as it is not an oral hypoglycemic biguanide.

Correct Answer: C

Rationale: The correct answer is C: GI disturbance. Cyclosporine A is known to cause gastrointestinal (GI) disturbances as a common side effect, including nausea, vomiting, abdominal pain, and diarrhea. This is due to its impact on the digestive system. Choice A (Diarrhea) is too specific and not the most common side effect. Choice B (Headache) is not a typical side effect of cyclosporine A. Choice D (Immunosuppression) is the intended therapeutic effect of cyclosporine A, not a side effect. Therefore, C is the correct choice based on the common side effects associated with cyclosporine A.

Correct Answer: D

Rationale: Step-by-step rationale for why D (Pellagra) is correct: 1. Dermatitis: Pellagra is characterized by skin rashes due to niacin deficiency. 2. Diarrhoea: Niacin deficiency in Pellagra affects the digestive system, leading to diarrhea. 3. Dementia: Niacin deficiency affects the brain, causing neurological symptoms like dementia. Summary of why other choices are incorrect: A: Dry beriberi is caused by thiamine (B1) deficiency, not niacin. B: Pyridoxine deficiency (vitamin B6) does not typically present with dermatitis, diarrhea, or dementia. C: Scurvy is caused by vitamin C deficiency and is characterized by bleeding gums, weakness, and fatigue, not the symptoms mentioned in the question.

Correct Answer: C

Rationale: The correct answer is C. Gemfibrozil (Lopid) has not been shown to reduce mortality associated with heart disease. This statement is false as fibric acid derivatives, including gemfibrozil, primarily work by lowering triglycerides and increasing HDL cholesterol levels, which may help in reducing the risk of heart disease but not mortality directly. Choices A, B, and D are all true statements about fibric acid derivatives. A: Clofibrate is indeed used for Type III hyperlipidemia. B: Gemfibrozil increases HDL cholesterol and lowers LDL cholesterol. D: Gemfibrozil is generally well tolerated with common side effects being gastrointestinal upset and myopathy.

Correct Answer: B

Rationale: The correct answer is B: Metastatic calcifications. Vitamin D3 can lead to hypercalcemia, causing calcium to deposit in soft tissues like blood vessels and kidneys, leading to metastatic calcifications. Choice A is incorrect because vitamin D deficiency, not excess, causes defective bone mineralization. Choice C is incorrect as vitamin D toxicity primarily affects calcium levels, not the liver. Choice D is incorrect as nephrolithiasis is more commonly associated with excess intake of calcium supplements, not vitamin D3.