McKenna's Pharmacology, 2e

10

P A R T 1  Introduction to nursing pharmacology

Orphan drugs Orphan drugs are drugs that have been discovered but are not financially viable and therefore have not been “adopted” by any drug company. Orphan drugs may be useful in treating a rare disease or they may have poten- tially dangerous adverse effects. Orphan drugs are often abandoned after preclinical trials or phase I studies. Some drugs in this book have orphan drug uses listed. More information about orphan drugs, and current listings, can be found at www.tga.gov.au/industry/ pm-orphan-drugs.htm. Over-the-counter drugs Over-the-counter (OTC) drugs are products that are available without prescription for self-treatment of a variety of complaints. Some of these agents were approved as prescription drugs but later were found to be very safe and useful for individuals without the need of a prescription. Some were not rigorously screened and tested by the current drug evaluation protocols because they were developed and marketed before the current laws were put into effect. Many of these drugs were “grandfathered” into use because they had been used for so long. The TGA is currently testing the effectiveness of many of these products and, in time, will evaluate all of them. Although OTC drugs have been found to be safe when taken as directed, nurses and midwives should consider several problems related to OTC drug use: • Taking these drugs could mask signs and symptoms of underlying disease, making diagnosis difficult. • Taking these drugs with prescription medications could result in drug interactions and interfere with drug therapy. • Not taking these drugs as directed could result in serious overdoses. Many people do not consider OTC drugs to be medi- cations and therefore do not report their use. Nurses and midwives must always include specific questions about OTC drug use when taking a drug history and should provide information in all drug-teaching protocols about avoiding OTC drug use while taking prescription drugs. ■■ Generic drugs are drugs no longer protected by patent and can be produced by companies other than the one that developed them. ■■ OTC drugs are available without a prescription and are deemed safe when used as directed. ■■ Orphan drugs are drugs that have been discovered but are not financially viable because they have a limited market or a narrow margin of safety. These drugs may have then been adopted for development by a drug company in exchange for tax incentives. KEY POINTS KEY POINTS

■■ BOX 1.2  Uniform scheduling of drugs and poisons in Australia

Schedule

Description

1

This schedule is left blank Substances available from

2 Pharmacy

Medicine

pharmacies, or from people licensed to sell these drugs Substances that require professional

3 Pharmacist

Only Medicine advice but are available from a pharmacist 4 Prescription Substances that are prescribed by a Only Medicine person permitted under state or

territory legislation to prescribe, and available from a pharmacy by prescription Hazardous substances that are available to the public but require care with handling Substances that are readily available to the public but are more hazardous, requiring strong warnings Substances that are highly harmful and require special manufacture, handling and use precautions Substances with potential for Substances that are prohibited due to the potential for abuse; use is limited to approved medical or scientific research purposes dependence

5 Caution

6 Poison

7 Dangerous

Poison

8 Controlled

Drug

9 Prohibited

Substance

Taken from Dempsey et al. p.748

have, they can produce the generic drugs more cheaply. In the past, some quality-control problems were found with generic products. For example, the binders used in a generic drug might not be the same as those used in the brand-name product. As a result, the way the body breaks down and uses the generic drug may differ from that of the brand-name product. In that case, the bioavailability of the drug is different from that of the brand name product. It is often recommended that a drug be dispensed in the generic form if one is available. This requirement helps to keep down the cost of drugs and healthcare. Some prescribers, however, specify that a drug prescrip- tion be “dispensed as written” (DAW), that is, that the brand-name product be used. By doing so, the prescriber ensures the quality control and the action and effect expected with that drug. These elements may be most important in drugs that have narrow safety margins, such as digoxin ( Lanoxin ), a heart drug, and warfarin ( Coumadin ), an anticoagulant. The initial cost may be higher, but some prescribers believe that, in the long run, the cost to the individual will be less.