McKenna's Pharmacology for Nursing, 2e

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P A R T 1  Introduction to nursing pharmacology

not be as dependent on the drug. With the new matrix delivery systems used for many medications, however, splitting the drug can cause it to become toxic or inef- fective. People should be specifically alerted to avoid cutting drugs when it could be dangerous, especially if they are being advised to cut other tablets to be eco- nomical. The cost of treating the toxic reactions may far exceed the cost of the original drug. Generic drug availability in many cases reduces the cost of a drug. Generic drugs are preparations that are off patent and therefore can be sold by their generic name, without the cost associated with brand-name products. Generic drugs are tested for bioequivalence with the brand-name product, and resulting infor- mation is available to prescribers. When a drug has a small margin of safety (a small difference between the therapeutic and the toxic dose), a prescriber may feel more comfortable ordering the drug by brand name to ensure that the dose and binders are what the prescriber expects. When “brand substitution not permitted” is on a prescription, the prescription is filled with the brand- name drug—such as Lanoxin instead of digoxin, or Coumadin instead of warfarin. In some situations the generic drug is not less expensive than the brand-name drug, so using only generic drugs does not guarantee that the person is getting the least expensive prepara- tion. Some pharmacies post the costs of commonly used drugs, and people may do a cost comparison to compare the relative cost of the same drug among various phar- macies or the cost differences among manufacturers of drugs and request that a different drug be prescribed. The nurse or midwife is often the person who is in the middle of this issue and must be able to explain the reason for the drug choice or request that the prescriber consider an alternative treatment. Table 6.2 presents an example of a cost comparison of some beta-blockers commonly used to treat hyper- tension. When deciding which drug to use, the person,

nurse or midwife may need to consider the range of costs. Drug Facts and Comparisons provides a cost compari- son of drugs in each class, and The Medical Letter on Drugs and Therapeutics provides cost comparisons of drugs that are reviewed in each issue. In the last few years, with the cost of drugs becoming a political as well as a social issue, many people have begun ordering drugs on the Internet, often from other countries. These drugs may be cheaper, do not require the person to see a healthcare provider (many of these sites simply have customers fill out a questionnaire that is reviewed by a doctor) and are delivered right to the person’s door. On checking, many discrepancies have been identified between what was ordered and what is in the product, as well as problems in the storage of these products. Some foreign brand names are the same as brand names in this country but are associated with dif- ferent generic drugs. Many warnings have been issued to consumers about the risk of taking some of these drugs without medical supervision, reminding consumers that they are not protected by Australian or New Zealand laws or regulations when they purchase drugs from other countries. The TGA website, www.tga.gov.au/ consumers/import.htm provides important information and guidelines for people who elect to use the Internet to get cheaper drugs. PHARMAC is part of New Zealand’s medicines system. The medicines system of New Zealand includes the Ministry of Health, MEDSAFE and District Health Boards, all working together to improve New Zea- landers access to and optimal use of medicines. The central role of PHARMAC is to manage the pharma- ceutical budget on behalf of District Health Boards and to decide which medicines are funded by the Govern- ment. For more information about PHARMAC, please access the website: www.pharmac.health.nz/about/ your-guide-to-pharmac. DRUG ABUSE Illicit drug use is a growing problem. Professional athletes are cited regularly for abusing anabolic steroids. High profile television and movie stars are often part of the drug scene, using street drugs —non-prescription drugs with no known therapeutic use—to enhance their mood and increase pleasure. Alcohol and nicotine are two commonly abused drugs that cause serious problems for the abuser or can interact with various drugs and alter a person’s response to a prescribed drug but that are often not seen as drug addiction issues. Parents are often very concerned that their children will use street drugs. The “everyone is doing it” argument is hard to counter when today’s heroes are thought to be heavily involved. Some people abuse and become addicted to prescription drugs following an injury, when confronted with chronic pain,

■■ TABLE 6.2 Generic or trade-name drugs?

Drug name

30-day supply Approximate cost of daily dose

atenolol (generic) Tenormin labetalol (generic) Trandate metoprolol (generic) Betaloc pindolol (generic) Visken propranolol (generic) Inderal

50–100 mg

$11.80 $15.98 $13.50 $21.40 $5.90 $9.99 $9.40 $7.39 $17.70 $31.50

200–800 mg

50–200 mg

10–30 mg

40–320 mg

This table shows general prescription prices for common beta-blockers used to treat hypertension. It is presented to illustrate the difference in pricing between generic and trade-name drugs.