Pharmacology Practice Quiz 4

Answer: B – Gout and hyperuricemia

Explanation: Prevent uric acid nephropathy, uric acid lithiasis, and gout during cancer therapy since chemotherapy causes the rapid destruction of cancer cells leading to excessive purine catabolism and uric acid formation. Allopurinol can induce myelosuppression and pancytopenia. Allopurinol does not have this function.

Answer: B – Intravesical administration

Explanation: Medications administered intravesically are instilled into the bladder. Intraventricular administration involves the ventricles of the brain. Intravascular administration involves blood vessels. Intrathecal administration involves the fluid surrounding the brain and spinal cord.

Answer: C – Myelosuppression

Explanation: The overall goal of cancer chemotherapy is to give a dose large enough to be lethal to the cancer cells, but small enough to be tolerable for normal cells. Unfortunately, some normal cells are affected including the bone marrow. Myelosuppression limits the body’s ability to prevent and fight infection, produce platelets for clotting, and manufacture red blood cells for oxygen portage. Even though the effects in options a, b, and d are uncomfortable and distressing to the patient, they do not have the potential for lethal outcomes that myelosuppression has.

Answer: A – Stimulating neuroreceptors in the medulla

Explanation: Vomiting (emesis) is initiated by a nucleus of cells located in the medulla called the vomiting center. This center coordinates a complex series of events involving pharyngeal, gastrointestinal, and abdominal wall contractions that lead to expulsion of gastric contents. Catecholamine inhibition does not induce vomiting. Chemotherapy does not induce vomiting from autonomic instability. Chemotherapy, especially oral agents, may have an irritating effect on the gastric mucosa.

Answer: D – It destroys the bone marrow prior to transplant.

Explanation: Myelo comes from the Greek word myelos, which means marrow. Ablation comes from the Latin word ablatio, which means removal. Thus, myeloablative chemotherapeurtic agents destroy the bone marrow. This procedure destroys normal bone marrow as well as the cancerous marrow. The patient’s bone marrow will be replaced with a bone marrow transplant. Myelocytes are not muscle cells Tumors are solid masses typically located in organs. Surgery may be performed to reduce tumor burden and require less chemotherapy afterward.

Answer: C – Before chemotherapy administration

Explanation: Nausea and vomiting (N&V) are common side effects of chemotherapy. Some patients are able to trigger these events prior to actually receiving chemotherapy by anticipating, or expecting, to have these effects. N&V occurring post-chemotherapeutic administration is not an anticipatory event but rather an effect of the drug. N&V occurring during the administration of chemotherapy is an effect of the drug.

Answer: C – The more drug bound to protein, the less available for desired effect

Explanation: Only an unbound drug can be distributed to active receptor sites. Therefore, the more of a drug that is bound to protein, the less it is available for the desired drug effect. Less drug is available if bound to protein. Distribution to receptor sites is irrelevant since the drug bound to protein cannot bind with a receptor site. Metabolism would not be increased. The liver will first have to remove the drug from the protein molecule before metabolism can occur. The protein is then free to return to circulation and be used again.

Answer: C – Enterohepatic cycling

Explanation: Drugs and drug metabolites with molecular weights higher than 300 may be excreted via the bile, stored in the gallbladder, delivered to the intestines by the bile duct, and then reabsorbed into the circulation. This process reduces the elimination of drugs and prolongs their half-life and duration of action in the body.

Answer: C – Decreased therapeutic effects of Drug A.

Explanation: Drug B will induce the cytochrome p-450 enzyme system of the liver; thus, increasing the metabolism of Drug A. Therefore, Drug A will be broken down faster and exert decreased therapeutic effects. Drug A will be metabolized faster, thus reducing, not increasing its therapeutic effect. Inducing the cytochrome p-450 system will not increase the adverse effects of Drug B. Drug B induces the cytochrome p-450 system but is not metabolized faster. Thus, the therapeutic effects of Drug B will not be decreased.

Answer: A – Adrenergic receptors

Explanation: Epinephrine (adrenaline) rapidly affects both alpha and beta adrenergic receptors eliciting a sympathetic (fight or flight) response. Muscarinic receptors are cholinergic receptors and are primarily located at parasympathetic junctions. Cholinergic receptors respond to acetylcholine stimulation. Cholinergic receptors include muscarinic and nicotinic receptors. Nicotinic receptors are cholinergic receptors activated by nicotine and found in autonomic ganglia and somatic neuromuscular junctions.