V04-10, V04-11, V04-12, V04-13

Although the class of anti-inflammatory drugs known as COX-2 inhibitors has proven successful at reducing pain and swelling, a series of clinical trials has shown that these drugs come with potentially harmful side effects. Anti-inflammatory drugs act on prostaglandins, hormone-like substances with a general regulatory role in the body – controlling blood flow to the kidneys or prompting contraction of the uterus during childbirth, for example – in addition to bearing the primary responsibility for causing pain and inflammation. Prostaglandins are the result of a process by which a type of acid in the cell membrane is transformed by two enzymes both known as cyclooxygenase, or COX-1 and COX-2. Older anti-inflammatory medications such as aspirin and ibuprofen stop pain by blocking the action of both COX enzymes. Researchers have long been aware, however, that the simultaneous repression of both COX-1 and COX-2 halts production of all prostaglandins, including those not responsible for pain.

Researchers who developed COX-2 inhibitors hoped to avoid negative side effects by blocking only one of the two COX enzymes. After a series of trials, drugs such as Vioxx and Celebrex entered the market in the 1990s. This approach, unfortunately, soon presented its own drawbacks. Although COX-2 inhibitors do in fact prevent production of prostaglandin E2 (PGE2), which is responsible for causing pain and inflammation, they also inhibit production of various other substances in the body, including prostacyclin (PGI2), which dilates blood vessels and prevents clots. On the other hand, COX-2 inhibitors do not prevent the production of thromboxane, another prostaglandin that constricts vessels and helps blood platelets clump. There is widespread agreement that the next step for researchers is to develop anti-inflammatory drugs that target specific prostaglandins rather than the enzymes that produce them.

1. Which of the following best describes the organization of the passage?

(a) Two options for anti-inflammatory drugs are compared.
(b) The history of a type of medication is outlined.
(c) The function of and problems with a type of medication are presented.
(d) The usefulness of a popular prescription is debated.
(e) New information is used to undermine old assumptions.


2.
According to the passage, a problem with COX-2 inhibitors arises for which of the following reasons?

COX-2 inhibitors


(a) often conflict with older types of anti-inflammatory medication.
(b) cause the production of an excessive amount of prostaglandin E2.
(c) do not suppress an excessive amount of thromboxane, which causes blood clots.
(d) do not account for the complexity of prostaglandin function.
(e) block the production of necessary regulatory substances.


3. Based on information in the passage, which of the following can be concluded about the function of the substance thromboxane?

(a) Thromboxane is responsible for several types of circulatory disorder.
(b) Prostaglandins are made in different cells than thromboxane.
(c) Aspirin does not affect the production of thromboxane.
(d) Thromboxane balances the effects of PGI2.
(e) Thromboxane plays an undetermined role in regulating inflammation.


4. It can be concluded from the passage that COX-2 inhibitors are in danger of accidentally disrupting which of the following bodily processes?

(a) constriction of blood vessels
(b) inflammation
(c) cell division
(d) kidney function
(e) enzyme production