Pharmacotherapeutics Questions and Answers

Answer: B

The answer is Faulty calcium metabolism causing decalcification, bone softening and deformity.

Paget's disease of bone (osteitis deformans) is a disorder of bone remodelling. Overactive osteoclasts resorb bone, and new bone is then laid down in a disorganised way, so the bones become enlarged, weakened and deformed, typically the skull, spine, pelvis and legs. The key's wording, a defect of calcium metabolism with decalcification, softening and deformity, is the textbook description used in pharmacy courses, where calcitonin and bisphosphonates are its treatment.

Faulty iron metabolism causes anaemia, vitamin C deficiency causes scurvy, and vitamin D deficiency causes rickets in children. None of these is Paget's disease.

Answer: C

Drug levels should be monitored in the treatment of epilepsy.

Several antiepileptics, phenytoin above all, have a narrow therapeutic range, wide variation between patients and, for phenytoin, saturation (zero-order) kinetics, so a small dose change can cause toxicity. Their effect is also hard to judge clinically, since the aim is the absence of seizures, so plasma levels are measured to guide the dose.

In hypertension and diabetes the effect is measured directly as blood pressure and blood glucose, so drug levels are not needed. In asthma, levels matter only for theophylline, which is now little used, not for the inhalers that make up most treatment.