Q- Which of the following drugs reduces blood pressure by centrally acting on vasomotor centers?
B- Clonidine- It is not indicated for initial therapy of hypertension but it may be used later in combination with other drugs. Its use leads to central alpha 2-adrenergic stimulation which results in decreased sympathetic outflow to the heart, kidney and peripheral vessels.
Q- Which of the following drugs may cause reversible gynecomastia?
A- Cimetidine- It may causes headache and gynecomastia in 2-4% of patients. It also can cause dizziness and somnolence.
Q- Which of the following is the most accurate definition of tachyphylaxis?
A- A decrease of the effect of drugs after use for a prolonged time
B- A drug interaction between two drugs
C- A toxic effect after repeated use of the same drugs in a short period of time
D- Very rapidly developing tolerance for a drug
C- Very rapidly developing tolerance for a drug- It is a rapid diminishing response to drugs after successive doses. It is common in neurologic and psychiatric drugs.