McKenna's Pharmacology for Nursing, 2e

■■ Beta-blockers are drugs use receptors within the SNS. T a wide range of conditions, stage fright, migraines, angi ■■ Non-selective blockade of al a loss o the reflex bronchod sympathetic stimulation. Th drugs in individuals who sm seasonal rhinitis, asthma or decrease the ris related to abrup Provide support an and discomfort, Provide teaching r precautions an Evaluatio Evaluate drug effec d crease i ess Monitor for advers confusion; sexu respiratory prob watch for and specific mea ■ ■ Monitor the effectiveness o compliance with the regim throughout dru Taper the drug gra CRITICAL THINKING Why did M.R. have such a severe r measures should be taken to e fully and does not re-experien What sort of support will M.R. an going through such a frighten about the children who may h respiratory arrest and how the depending on their ages. Thin wife may need and the fear that with M.R.’s condition. M.R. has b for several months and needs to continue the drug with modifica addition of other drugs to deal What kind of teaching program to help M.R. deal with this dru effects? is a non-selective beta-adrenergic stim lating activi response to such It stabilis s c rtai decrease your tre You should lear writing the pulse rate is 82 beats/ • Never discontinu find that your pre healthcare provi tapered over tim us is disc ntinu may occur: • F tigue, weakne throughout the • Dizziness, drows avoid driving, o delicate tasks. spells. • Change in sexu effect and disc Monitor for drug– Evaluate the effecti Evaluate the effecti

eneration cephazo- cef ). effective s well as enes and cond-gen- -positive xitin and are effec- rains, are a but are i, as well PeCKS ). ftazidime develop- axipime ), ive organ- hylococci in devel- esistance. inforo ) is ve organ- hlococcus ptococcus bacterio- cific drug basically f bacteria bacteria cell walls. and burst e cell (see atment of Table 9.3 Selection the sen- of choice ortant to situations appearing , perform causative

Usual indications • Web links alert the student to electronic sources of drug information and sou ces of drug therapy information for specific diseases. An extensive range of additional resources to enhance teaching and learning and to facilitate understanding of this chapter may be found online at the text’s ccompanying website, located on thePoint at http://thepoint.lww.com. These include Watch and Learn videos, Concepts in Action animations, journal articles, review questions, case studies, discussion topics and quizzes. with his healthcare provider. He also may want to include his family in this discussion. It should be stressed that he did so well up to this point because he had not been exposed to pollen and th refore had not had the problem that brought him into the hospital this time. M.R. probably never reported the occurrence of hay fever to his healthcare provider when the drug was prescribed because it had never been a problem and probably did not seem significant to him. M.R. and his family should receive support a d be encouraged to talk about what happened and how they reacted to it. It i normal to feel frightened and unsure when love one is in distress. They should e involved in the discussion of wh medical regimen would be mo t appropriate for M.R. at this point. C H A P T E R 3 1 Adrenergic blocking antagonists E sure safe and appropriate admini tr tion of the drug. Provide comfort a d safety measures: assistance/side rails; temperature control; rest peri ds; mouth care; small, frequent meals. Monitor blood pressure, pulse, and respir tory status throughout drug therapy. Tap r the drug gra ually if it is to b discontinued to dec ease the risk of severe hypertension, MI or stroke rel ted to abrupt withdrawal. Provide support and reassuranc to deal with drug effects and dis omfort, sexual dysfunction and fatigue. Pro i e teaching regarding drug name, dosage, side effects, precautions and warning signs to report. Evaluation Evaluate rug effects: blood pressure within normal limits, decrease in essential tr mors, stabilised cardiac rhythm. Monitor for adverse ffect : CV effects: HF, blo ; dizziness, confusion; exual dy funct on; GI eff ct ; hypoglycaemia; resp ratory probl ms. Monitor for drug–drug interactions as indicated. Evaluate the effectivene s of the teaching program. Evaluate the effectiveness of comfort and safety measures. TEACHING FOR M.R. • The drug that has been prescribed for you, propranolol, is a non-selective beta-ad energic blocking agent. A beta-adrenergic blocking agent works to prevent certain timulating tivities that ormally occur in the body in response o such fact rs as stress, injury or excitement. It s abilises cer ai ner e membranes, which helps to decrease your tremor. You should learn to take your pulse and monitor it daily, writing the pulse rate on the calendar. Your current pulse rate is 82 beats/minute. • Never discontinue thi medi tion suddenly. If you find that your prescription is running low, notify your healthcare provider at once. This drug needs to be tap r d over time t prevent severe reactions when its us is discontinued. Some of the following adverse effects ay occur: • Fatigue, weakness : Try to stagger your activities throughout the day to allow rest periods. • Dizziness, drowsiness : If these should occur, take care to avoid driving, operating dangerous machinery or doing delicate tasks. Change position slowly to avoid dizzy spells. • Change in sexual functi n : Be assured that this is a drug effect an discuss it with your healthcare provider. ■■ Orphan drugs are chemicals that hav been d scovered to have some therapeutic effect but at are not financially advantageou t develop int drugs. ■■ OTC drugs are available with ut prescription for the self-treatment of various complaints. ■■ Information about drugs can be obtained from a variety of sources, including the drug label, reference books, journals and Internet sites. Knowing your strengths and weaknesses helps you to study more effectively. Take a PrepU Practice Quiz to find out how you measure up! Healthcare providers and students may want to consult the following Internet sources: www.anztpa.org Home pag of the Australia New Zealand Therapeutic Product Agency (ANZTPA). www.australianprescriber.com Austr lian Prescriber home p ge. www.m dsafe.govt.nz Home p ge of MEDSAFE New Zealand. www.nps.org.au Home page of MedicineWise, National Prescribing Service. www.tga.gov.au Review the person’s history for allergy to propranolol, HF, shock, bradycardia, heart block, hypotension, COPD, thyroid disease, diabetes, respiratory impairment, and concurrent use of barbiturates, non-steroidal anti- inflammatory drugs, piroxicam, sulindac, lignocaine, cimetidine, phenothiazines, clonidine, theophylline and rifampicin. Focus the physical examination on the following: CV: blood pressure, pulse, peripheral perfusion, ECG CNS: orientation, affect, reflexes, vision The care plan is followed by a checklist of teaching points designed for the person presented in the ca e study. This approach helps the student to see how assessment and the collected data are applied in the clinical situation. 481 577 85 complaining of tremor in his hands that eventually made it very difficult for him to work as a computer programmer. A diagnosis of essential tremor was made, and he was prescribed propranolol ( Inderal ) 40 mg twice daily. M.R. had good effects with the drug and had no further problems until the following June, when acute respiratory distress developed while he was picnicking in a stat park with his family. On the way to the emergency room, he suffered an apparent respirat ry arrest. He was admitted to the hospital nd placed in he respiratory intensive care unit. It was found that M.R. had a history of hay fever and allergic rhinitis during the pollen season but had never experienced such a severe reaction. CARE GUIDE FOR M.R.: PROPRANOLOL Assessment: History and ex mination Skin: colour, lesions, texture GU: urinary output, sexual function GI: abdominal, liver evaluation Respiratory: respirations, adventitious sounds Implement tion THE SITUATION M.R., a 59-year-old man, has been seen several times • Critical thinking scenarios tie each chapter’s content together by presenting clinical scenarios about a person using a particular drug from the class being discussed. Included in the case study are hints to guide critical thinking about the case and a discussion of drug- and nondrug-related care considerations for that particular person and situation. Most importantly, the case study also provides a plan of care specifically developed for that person. ■ ■ Offer support and encouragement to help the person deal with the drug regimen. ■ ■ Provide thorough teaching, including drug name, dose and schedule of administration; use of drug with food or meals, if appropriate; possible adverse effects and measures to prevent them; warning signs to report; safety measures, such as changing position slowly, avoiding driving or using hazar ous machinery, and pacing activities; and the need for follow-up evaluation and become narrower, his swollen bronchial tubes were unable to allow air to flow through them. The result was bronchial constriction and respiratory distress that, in M.R.’s case, progressed to a respiratory arrest. Before he began taki g propranolol, M.R. probably had been eff ctively compensating for the swelling of the bronchi through bronchodilation and had never experienced such a reaction. There are few other drugs for treating essential tremor. M.R. and his healthcare providers will eed to decide whether the benefit that the drug has brought t him is wo th the potential for adverse effects. They might be able to suggest additional drugs to deal with the seasonal allergic reactions to make the use of the propranolol safer for M.R. M.R. may want to discuss this frightening incident KEY POINTS CNS effects occur to prevent injury; provide small, frequent meals and mouth care to help relieve the discomfort of GI effects ; establish a daily activity program, spacing activities to help the person deal with activity intolerance . that occurs when th SNS is stimulate . When the pollen react d with M.R.’s airways, causing them to swell and

x the GI tract: the first-generation drug cephalexin; the second-generation drugs cefaclor and cefuroxime; the third-generation drug cefotaxime; and the fourth- generation drug cefepime. The others are absorbed well after IM injection or IV administration. (Box 9.4 provides calculation practice using cefaclor.) The cephalosporins are primarily metabolised in the liver and excreted in the ur ne. These drugs cross the placenta and enter breast milk (see contraindications and cautions). Preface • Focus on calculations reviews are designed to help the student hone calculation and measurement skills while learning about the drugs for which doses might need to be calculated.

Calculations

BOX 9.4

You are caring for a 20-kg child with a severe case of tonsillitis. An order is written for cefaclor (Ceclor) 20 mg/kg/day q 8 hours for 10 days.The drug comes in an oral suspension 125 mg/5 mL. What amount should you administer at each dose? The order is for 20 mg/kg, so 20 mg/kg × 20 = 400 mg per day.

CRITICAL THINKING SCENARIO Non-selective beta-blockers (propranolol) TEACHING FOR • The drug that ha

stock required stock strength • Focus on drug therapy across the lifespan boxes concisely summarise points to consider when using the drugs of each class with children, adults, pregnant and breastfeeding women, and the elderly. volume 1 400 125 × 5 1 = 2000 125 = 16 mL/day therefore, each dose = 16/3 = 5.3 mL per dose Contraindications and cautions Avoid the use of cephalosporins in people with known allergies to cephalosporins or penicillins because cross-sensitivity is common. Use with caution in people with hepatic or renal impairment because these drugs are toxic to the kidneys and could interfere with the metabolism and excretion of the drug. In addition, use with caution in pregnant or breastfeeding women because potential effects on the fetus and infant are not known; use only if the benefits clearly outweigh the potential risk of toxicity to the fetus or infant. Reserve cephalosporins for appropriate situations because cephalosporin-resistant bacteria are appearing in increasing numbers. Before therapy begins, perform a culture and sensitivity test to evaluate the causative organism and appropriate sensitivity to the antibiotic being used. Adverse effects The most common adverse effects of the cephalo- sporins involve the GI tract and include nausea, Opioids CHILDREN The safety and effectiveness of many of these drugs have not been established in children. If an opioid is used, the dose should be calculated very carefully, and the child should be monitored closely for the adv se effects associated with opioid use. Opioids that have an established paediatric dose include codeine, fentanyl (but not transdermal fentanyl), hydrocodone, pethidine and morphine. Oxycodone and dextropropoxyphene are not recommended for children. Methadone is not recommended a an an lgesic in children. If a hild older than 16 ye rs of age requires an opioid agonist-antagonist, buprenorphine-naloxone is the preparation of choice. Naloxone is the drug of choice for reversal of opioid effects and opioid overdose in children. ADULTS Adults being treated for acute pain should be reassured that the risk of addiction to an opioid during treatment is remote.They should be encouraged to ask for pain medication before the pain is acute, to get better coverage for their pain. Many institutions allow people to self-regulate intravenous drips to control their pain postoperatively. PREGNANCY AND BREASTFEEDING The opioids are contraindicated or should only be used with caution during pregnancy because of the potential for • Focus on gender considerations and Focus on ultural considerations discussio s encourage the student to t ink ab ut cultural awaren ss and to consider the person as a unique individual with a special se of characte istics that not only influences vari tions in drug e fectiveness, but also could influence a person’s perspective on drug therapy. 410 P A R T 4 Drugs acting on the central and peripheral nervous systems Headache distribution Headaches are dis ributed in the general pop lation in a definite gender-related pattern. For example: • Migraine headaches are thr e times more likely to occur in women than men. • Cluster headaches are more likely to occur in men than in women. • Tension headaches are more likely to occur in women than in men. There is some speculation that the female Gen er considerations BOX 26.4 increase in type 2 diabetes in young people. The treat- ment of Type 2 diabetes usually begins with changes in diet and exercise. Di ting controls the amount and timing of glucose introduction into the body, and weight loss decreases the number of insulin receptor sites that need to be stimulated, as well as the intra-abdominal fat that blocks adiponectin release. Exercise increases the movem nt of glucose i to the cells by ympathetic nervous system (SNS) activation and by t e increase pot ssium in the blood that occurs directly after exercising. Potas- sium acts as part of a polarising system during exercise that pushes glucose into the cells. Clinical studies have shown that controlling serum glucose levels can d crease th risk of complication by up to 40% (ADA, 2008). When diet and exercise no longer work, other agents (discussed later) are used to stimulate the production of insulin in the pancreas, increase the sensitivity of the insulin receptor sites, or control the entry of glucose into the system. Injection of insulin may eventually be needed. This co cept is oft n fusing for people who are learning abo t iabetes. Type 2 diabetes often evolves until insulin is needed. Timing of the injections of insulin is correlated wit food intake a d anticipated increases in blood glucose levels, as well as exercise levels and anticipated stress (ADA, 2008). See Box 38.4 Cultural considerations BOX 38.3 Preventing resistance Because the emergence of resistant strains of microbes is s rious publi health roblem that continues to grow, healthcare providers must work together to prevent the emergence of resistant pathogens. Exposure to an anti- micr bial agent lea s to the development of resistance, so it is important to limit the use of antimicrobial agents to the treatment of specific pathogens known to be sen- sitive to the drug being used. Drug dosing is important in preventing the develop- ment of resistance. Doses shoul be high enough and the uration of rug therapy should be long enough to eradicate ev n slightly re istant microorganisms. The recommended dosage for a specific anti-infective agent takes this issue i to account. Around-the-clock dosing eliminates the peaks and valleys in drug concentration and helps to maintain a constant therapeutic level to prevent the emergence of resistant microbes during times of low concentration. The duration of drug use is critical to ensure that the microbes are completely, not partially, eliminated and are not given the chance to grow and develop resistant strains. It has proved to be difficult to convince people who are taking anti-infective drugs that the timing f doses an the length of time they continue to take the drug are important. Many people stop taking a drug once they start to feel better and then keep the rem ining pills to treat themselves at s time in e futur when they do not feel well. This practice favours the emergence of resistant strains. Box 8.4 gives ti s on teachi g about this. 12 BOX 26.1 Drug therapy across the lifespan TABLE 26.1 DRUGS IN FOCUS Opioids Drug name predisposition to migraine headaches may be related to the vascular sensitivity to hormones. Some women can directly plot migraine occurrence to periods of fluctuations in their menstrual cycle.The introduction of the triptan class of antimigraine drugs has been beneficial for many of these women. Diabetes and blood glucose variations Certain ethnic groups tend to have a genetically predetermined variation in blood glucose levels, possibly caused by a variation in metabolism. In New Zealand, certain ethnic groups (particularly Ma– ori, Pacific Islanders and South Asians) are at a higher risk of developing diabetes and data suggests that the incidence of diabetes for Ma– ori and Pacific peoples are more than three times higher than the European rates and Ma– ori and Pacific peoples are more than five times as likely to die from type 2 diabetes. Similarly, it has been estimated that Indigenous Australians have a three times higher incidence of type 2 diabetes than the non-Indigenous population, and are twice as likely to die from a diabetes- related condition. People in these groups should be screened regularly for t pe 2 diabetes.They ca also benefit from teaching about warning signs of diabetes. Beyond Australia and New Zealand, similar problems exist for many cultural groups including First Nation people in Canada, and African and Native Americans. The clinical importance of this relates to proper screening of individuals for hypoglycaemia and diabetes mellitus. Individuals in these groups who have fasting glucose tolerance tests need to hav the standard readjusted before a diagnosis is made. Such people also require an understanding of potential diff rences in normal levels on hom blood glucos monitoring units • Focus on individual and family teaching boxes review i portant points to c ver as par of individual and family education. H alth are providers should also be cautious about the in iscriminate use of anti-infectives. Antibiotics are not effective in the treatment of viral infections or illnesses such as the common cold. However, many people seek prescriptions for these drugs when they visit practitioners because they are convinced that they need to take som thing to f el better. Healthcare providers who prescribe anti-infectives without knowing the caus- ative organism and which drugs might be appropriate U ing anti-infective agents When teaching people who are prescribed an anti- infective agent, it is important to alw ys include some general points: • This drug is prescribed for treating the particular infection that you have now. Do not use this drug to treat other infections. • This d ug needs to be ken as prescribed—for the correct number of times each day and for the full Individual and family teaching BOX 8.4 CARE GUIDE FOR M.R.: PROPRANOLOL Assessment: History and examination Focus the physical examination on the following: CV: blood pressure, pulse, peripheral perfusion, ECG CNS: orientation, affect, reflexes, vision CHAPTER SUMMARY ■■ Drugs re chemicals that are introduced into the body to bring about some sort of change. ■■ Drugs can come from many sources: plants, animals, inorganic eleme ts and synthetic preparations. ■■ The TGA reg lates the development and marketing of drugs to ensure safety and efficacy in Australia. Dosage/route Opioid agonists alfentanil (Rapifen) Spontaneous ventilation: 7 mcg/kg by slow IV injection Controlled ventilation: 20-50 mcg/kg by slow IV injection Adult: 15–60 mg PO, IM, IV or SC q 4–6 hours; 10–20 mg PO q 4–6 hours for cough Paediatric: 0.5 mg/kg PO, IM or SC q 4–6 hours; 2.5–10 mg PO q 4–6 hours for cough R view the p rso ’s istory for allergy to propranolol, HF, shock, bradycardia, heart block, hypotension, COPD, thyroid disease, diabetes, respiratory impairment, and concurrent use of barbiturates, non-steroidal anti- inflammatory drugs, piroxicam, sulindac, lignocaine, cimetidine, phenothiazines, clonidine, th ophylline and rifampicin. codeine (generic) Migraines are generally classified as common or classic. Common migraines, which occur without an aura, cause severe, unilateral, pulsating pain that is frequently accompanied by nausea, vomiting and sensi- tivity to light and sound. Such migraine headaches are often aggravated by physical activity. Classic migraines are usually preceded by an aura—a sensation involving sensory or motor disturbances—that usually occurs about half an hour before the pain begins. The pain and adverse effects are the same as those of the common migraine. It is believed that the underlying cause of migraine headaches is arterial dilation. Headaches accompanied by an aura are associated with hypoperfusion of the brain during the aura stage, followed by reflex arterial dilation and hyperperfusion. The underlying cause dextropropoxyphene (Doloxene) 100 mg PO q 4 hours as needed fentanyl (Actiq, Duragesic, Sublimaze) Adult: 0.05–0.1 mg IM, 30–60 minutes before surgery; 0.002 mg/kg IV or IM during surgery; 0.05–0.1 mg postoperatively; 5 mcg/kg transmucosally; for transdermal patch, calculate the previous day’s opioids need and use table to convert to patch strength; ionic delivery system, 40 mcg over 10 minutes Paediatric (>2 years): 2–3 mcg/kg IM or IV; base transmucosal dose on weight and do × DISCUSSION Pro ranolol, a non-s lective beta- l ck r, was prescribed to decrease the tremor he was experiencing. The exact action of this drug to decrease the tremor is thought to be related to its membrane-stabilising properties. The desired therapeutic effect is the reduction of the tremor, but all of the beta-blocking effects will occur and need to be monitored. He did well on the drug until pollen season arrived. That is because propranolol, a non-selective beta- blocker, prevented the compensatory bronchodilatio that occurs whe the SNS is stimulated. When the pollen reacted with M.R.’s airways, causing them to swell and bec me arrower, his swollen bronchial tubes were unable to allow air to flow through them. The result was bronchial constriction and respiratory distress that, in M.R.’s case, progressed to a respiratory arrest. Before he egan t king propranolol, M.R. probab y had b en effectively compensating for the swelling of the bronchi through bronchodilation and had never experienced such a reaction. There are few other drugs for treating essential tremor. M.R. and his healthcare providers will need to de ide whether the benefit that the drug has brought to him is worth the potential for adverse effects. They might be able to suggest additional drugs to deal with the seasonal allergic reactions t make the use of the propranolol safer for M.R. M.R. may want to discuss this frightening incident with his healthcare provider. He also may want to include his family in this discussion. It should be stressed that he id so well up to th s int because e had not been exposed to pollen a d therefore had not had th problem that brought him into the hospital this time. M.R. probably nev r reported th occurrence of hay fever to his healthcare provider when the drug was prescribed because it had never been a problem and probably did not seem significant to him. M.R. and his family should r ceive support and be encouraged to talk about what happened and how they reacted to it. It is normal to feel frightened and unsure when a loved one is in distress. They should be involved in the dis ussi n of what medical regimen would be most appr priate for M.R. at this point. P A R T 1 Introduction to nursin pharmacology Therapeutic G idelines provides a wide range of drug information in a series of systematic guides, such as antibiotics and gastr intestinal pharmacology. These guidelines draw upon a range of evaluated lit rature and re arch. McKenna’s Drug Handbo k for Nursing and Mid- wifery has dr g monographs organised alphabetically and includes care implications and import nt teaching points specifically releva t to nursing nd midwifery ractice. Numerous other drug handbooks are also on the market and readily available for nurses and midwives to use. Jou nals Variou journals can be used to obtain drug informa- tion. F r xamp e, t e Medical Letter is a mo thly review of n w drugs, drug classes and specific treat- m nt protocols. Many cli ical nursing and midwifery journals offer information on new drugs, drug errors and care im li ations. Austral an Prescriber is a usef l source of easily interpreted pharmacology information nd is freely avail ble onli e. Internet information Many individuals now use the Internet as a source of medical information and advice. Nurses and midwives need to become familiar with what is available o the Inter et and what people may be referencing, and h ve skills in critiquing the credibility of th se s urces.

C H A P T E R 2 6 Opioids, opioid antagonists and antimigraine agents 401

adverse effects on the fetus.These drugs enter breast milk and can cause opioid effects in the baby, so caution should be used during breastfeeding. Morphine and pethidine are often used for analgesia for labour.The mother should be monitored closely for adverse reactions, and, if the drug is used over a prolonged labour, the newborn infant should be monitored for opioid effects such as respiratory depression. Naloxone should be readily available for the baby if the mother has received an opioid in the hours immediately prior to the birth. OLDER ADULTS Elderly people should be specifically asked whether they require pain medication. Because many older people can recall a time when nurses were able to spend more time with people, they may tend to believe that the nurse will meet their needs. Older people are more likely to experience the adverse effects associated with these drugs, including central nervous system, gastrointestinal and cardiovascular effects. Because older people often have renal or hepatic impairment, they are also more likely to have toxic levels of the drug related to changes in metabolism and excretion.The older person should have safety measures in effect—side rails, call light, assistance to ambulate—when receiving one of these drugs in the hospital setting. and continued state of arterial dilation are not clearly understood, but they may be related to the release of bradykinins or serotonin, or as a response to other hormon s a d chemicals. ANTIMIGRAINE AGENTS For many years, the one standard treatment for migraine headaches was acute analgesia, often involving an opioid, together with control of lighting and sound and the use of ergot derivatives. In the late 1990s, a new class of drugs, the triptans, was found to be extremely effec- tive in treating migraine headaches without the adverse effects associated with ergot derivative use. Because these agents are associated with many syst mic adverse effects, their usefulness is limited in some p ople (see Box 26.5). Table 26.2 includes additional information about each class of antimigraine agents. E rgot dErivativEs The ergot derivatives cause constriction of cranial blood vessels and decrease the pulsation of cranial arteries. As a result, they reduce the hyperperfusion of the basilar artery vascular bed. Available ergot derivatives include ergotamine ( Cafergot ) (no longer available in Austr lia). Therapeutic actions and indications The ergot derivatives block alpha-adrenergic and sero- tonin receptor sites in the brain to cause a constriction of cranial vessels, a decrease in cranial artery pulsa- tion and a decrease in the hyperperfusion of the basilar Managing glucose levels during stress The body has many compensatory mechanisms for ensuring that bloo glucose levels stay within a safe range.The sympath tic stress reaction elevates blood glucose levels to provide ready energy for fight or flight (see Chapter 29).The stress reaction causes the breakdown of glycogen to release glucose and the breakdown of fat and proteins to release other energy. STRESS REACTIONS The stress reactio elevates the blood glucose concentration above the normal range. In severe stress situations—such as an acute myocardial infarction or a car c ash—the blood glucose level can be very high (above 8.0 mmol/L).The body uses that energy to fight the in ult or flee from th ressor. Nurses and midwives in acute care situations need to be ware of this refl x elevation in glucos when caring for people in cute stress, specially people in emergency situations whose medical hist ry is unknown.The usual medical re p nse to a blood glucose concentration of above 8.8 mmol/L would be the administration of insuli . In many situatio s, that is exactly what is done, especially if the person’s history is not known and the effects of such a high glucose level could cause severe systemic reactions. Insulin ad inistration causes a drop in the blood gluc se level as glucose enters cells to be either used for energy or converted to glycogen for storage. However, a problem may arise in the acute care s tting, particularly in a non-diab tic person. Relieving the stress r act on can also drop glucos l vels as the stimulus to increase these levels is lost and the glucose that was there is used for energy. A person in this situation who has been treated with insulin is at risk for development of potentially severe hypoglycaemia.The body’s response to low glucose levels is a sympathetic stress reaction, which again elevates the blood glucose c ncentration. If tre ted, the person potentially can enter a cycle of high and low glucose levels. BEST CARE PRACTICE Nurses and midwives are often the ones in closest contact with the highly stressed person—in the emergency room, the intensive care unit, the post- anaesthesia room—and should be constantly aw re of the normal and refl x changes in blo d g ucose t at accompany stress. Careful mon tori g, with awar ness of stress and the relief of stress, can prevent a prolonged treatment program to maintain blood glucose levels within the range of normal, a situation that is not “normal” during a stress reaction. Diabetic people who are i severe stress situations require changes in their insulin doses.They should be allowed some elevation of blood glucose, even though their inability to produce sufficient insulin will make it difficult for their cells to make effective use of the increased glucose levels. It is a clinical challenge to The evide ce BOX 38.4 are promoting the emergence of resistant strains of microbes. With many serious illnesse , including pneu- monias for which the causative organism is suspected, antibiotic therapy may be started as soon as a sample of the bacteria, or culture , is taken and before the results are known. Healthcare provid rs also tend to try newly introduced, m re powerful drugs wh n more estab- lished drug may be just as eff ctive. Use of a powerful drug in this way leads to the rapid emergence of resistant strains to that drug, perhaps limiting its potential use- fulness when it might be truly nece sary. KEY POINTS ■■ The goal of anti-infectiv therapy is th r duction of the invading organisms to a point at which the human immune response can take care of the infection. ■■ Anti-infectives can act t de troy an infective pathogen (bactericidal) or to prevent the pathogen from repro ucing (bacteriostatic). ■■ Anti-infectives can have a small group of pathogens against which they are effective (narrow spectrum), or they ca be eff ctive against many pathogens (broad spectrum). Using anti-infective agents Anti-infective agents are used to tr at systemic infec- tions and sometimes as a means of prophylaxis (to prevent infections before they occur). Treatment of systemic inf ctions Many infections that once led to l ngthy, organ-damaging or even fatal illnesses are n w managed quickly and effi- ciently with the use of systemic anti-infective agents. Before the introduction of penicillin to treat strepto- coccal infections, many people developed rheumatic fever with serious cardiac complications. Today, rheu- matic fever and the resultant cardiac valve defects are seldom seen. Several factors should be considered efore beginning one of these chem therapeutic r gimens to ensure that the person obtains the greatest benefit possible with th fewest adverse effects. These factors include identificati n of the correct pathogen and selec- tion of a drug that is most ikely to (1) c use the least complications for that person and (2) be most effective against the pathogen involved. Identification of the pathogen Identificat on f the infecting pathoge is d ne by cul- turing a tissue sample from the infected area. Bacteri l cultures re performed in a laboratory, i which a sw b KEY POINTS ONLINE RESOURCES WEB LINKS Analgesic supplement and anaesthetic induction agent in inpatient surgery Relief of mild to moderate pain; relief of coughing induced by mechanical or chemical irritation of the respiratory tract Relief of mild to moderate pain in adults Special considerations: limit use in suicidal or addiction-prone people For analgesia before, during and after surgery; transdermal patch for management of chronic pain; control of breakthrough pain C H A P T E R 3 8 Agents to control blood glucose levels C H A P T E R 8 Anti-infective agents