By T. Lester. State University of New York College at Potsdam. 2018.
Glucocorticoids inﬂuence carbohydrate Progesterone helps prepare the uterus for pregnancy and the mam- storage quality accutane 10mg, exert anti-inﬂammatory effects discount accutane 40mg otc, suppress corticotropin se- mary glands for lactation. Mineralocorticoids help Testicular hormone (male sex hormone) is testosterone, which regulate electrolyte balance, mainly by promoting sodium retention regulates development of masculine characteristics. Placental hormones are chorionic gonadotropin, estrogen, The adrenal medulla hormones are epinephrine and norepinephrine progesterone, and human placental lactogen, all of which are con- (see Chap. The anterior pituitary, in turn, secretes hormones that mones can affect a single tissue or function (eg, catecholamines, act on target tissues, usually to stimulate production of other glucagon, secretin, and prolactin regulate lipolysis [release of hormones. For example, hypothalamic corticotropin-releasing fatty acids from adipose tissue]). For ex- cotropin, and corticotropin, in turn, stimulates the adrenal ample, ACTH, cortisol, and growth hormone are secreted in cortex to produce cortisol. This complex interrelationship is 24-hour (circadian) cycles, whereas estrogen and progestin often referred to as the hypothalamic–pituitary–adrenocortical secretion is related to the 28-day menstrual cycle. It functions by a negative feedback system, in which hormone secretion is stimulated when hormones are needed and inhibited when they are not needed. The hypothalamic– Hormone Pharmacokinetics pituitary–thyroid axis also functions by a negative feedback mechanism. Protein-derived hormones (amines, amino acids, peptides, and polypeptides) are synthesized, stored, and released into the bloodstream in response to a stimulus. The steroid hor- GENERAL CHARACTERISTICS mones, which are synthesized in the adrenal cortex and go- OF HORMONES nads from cholesterol, are released as they are synthesized. Most hormones are constantly present in the blood; plasma Hormones are extremely important in regulating body activ- concentrations vary according to body needs, the rate of syn- ities. Their normal secretion and function help to maintain the thesis and release, and the rate of metabolism and excretion. Steroid and thyroid hormones are trans- interactions with other hormones and nonhormone chemical ported by speciﬁc carrier proteins synthesized in the liver. If this occurs, hormone effects are en- all endocrine functions are complex processes that are inﬂu- hanced because more unbound, active molecules are avail- enced by more than one hormone. Several mecha- hormone) affect almost all cells, whereas others affect spe- nisms operate to eliminate hormones from the body. The ciﬁc target tissues (eg, corticotropin stimulates the adrenal water-soluble, protein-derived hormones have a short dura- cortex). In addition, one hormone can affect different tissues tion of action and are inactivated by enzymes mainly in the (eg, ovarian estrogen can act on ovarian follicles to promote liver and kidneys. The lipid-soluble steroid and thyroid hor- their maturation, on the endometrial lining of the uterus to mones have a longer duration of action because they are stimulate its growth and cyclic changes, on breast tissue to bound to plasma proteins. Once released by the plasma pro- stimulate growth of milk ducts, and on the hypothalamic– teins, these hormones are conjugated in the liver to inactive CHAPTER 22 PHYSIOLOGY OF THE ENDOCRINE SYSTEM 323 forms and then excreted in bile or urine. A third, less com- hormones, calcitonin, glucagon, parathyroid hormone) and mon mechanism is inactivation by enzymes at receptor sites decreased by hormones that inactivate adenyl cyclase on target cells. Calcium is the second messenger for angiotensin II, a Hormone Action at the Cellular Level strong vasoconstrictor that participates in control of arterial blood pressure, and for gonadotropin-releasing hormone. The Hormones modify rather than initiate cellular reactions and postulated sequence of events is that hormone binding to re- functions. Once hormone molecules reach a responsive cell, ceptors increases intracellular calcium. The calcium binds they bind with receptors in the cell membrane (eg, cate- with an intracellular regulatory protein called calmodulin.
How does each medication work to restore the balance of neurotransmitters? What assessment data will you collect to evaluate whether the antiparkinson medications are effective? What assessment data should be collected to detect adverse effects of antiparkinson drugs? The correct balance of dopamine and acetylcholine is progressive purchase accutane 5mg amex, degenerative disorder of the central nervous important in regulating posture discount accutane 10mg with visa, muscle tone, and voluntary system (CNS) characterized by abnormalities in movement movement. It occurs equally in men and women, usually between brain dopamine and a relative increase in excitatory acetyl- 50 and 80 years of age. Imbalances of other neurotransmitters (eg, gamma from destruction or degenerative changes in dopamine- aminobutyric acid [GABA], glutamate, norepinephrine, and producing nerve cells. Early-onset parkin- ANTIPARKINSON DRUGS sonism (before 45 years) is thought to have a genetic com- ponent. Use of the newer atypical or inhibit the actions of acetylcholine (anticholinergic agents) antipsychotic drugs may reduce the incidence of drug-induced in the brain. If used for this purpose, a course of therapy of approximately 3 months is recommended because Levodopa, carbidopa, amantadine, bromocriptine, pergolide, symptoms usually subside by then even if the antipsychotic pramipexole, ropinirole, selegiline, entacapone, and tolcapone drug is continued. Car- Contraindications to Use bidopa is used only in conjunction with levodopa. Levodopa is contraindicated in clients with narrow-angle glaucoma, hemolytic anemia, severe angina pectoris, transient ischemic attacks, or a history of melanoma or undiagnosed Anticholinergic Drugs skin disorders, and in clients taking MAO inhibitor drugs. In addition, levodopa must be used with caution in clients with Anticholinergic drugs are discussed in Chapter 21 and are de- severe cardiovascular, pulmonary, renal, hepatic, or endocrine scribed here only in relation to their use in the treatment of disorders. Only anticholinergic drugs that are cen- and therefore are contraindicated in people hypersensitive trally active (ie, those that penetrate the blood–brain barrier) to ergot alkaloids or those with uncontrolled hypertension. Atropine and scopolamine Selegiline, entacapone, and tolcapone are contraindicated in are centrally active but are not used because of a high incidence people with hypersensitivity reactions to the drugs. In addition to the primary anticholinergic is contraindicated in people with impaired liver function. The drugs must be used cautiously in clients with cardiovascular Mechanisms of Action disorders (eg, tachycardia, dysrhythmias, hypertension) and liver or kidney disease. Dopaminergic drugs increase the amount of dopamine in the brain by various mechanisms. Amantadine increases dopamine release and decreases dopamine reuptake by presynaptic INDIVIDUAL ANTIPARKINSON DRUGS nerve fibers. Bromocriptine, pergolide, pramipexole, and ropinirole are dopamine agonists that directly stimulate post- Dopaminergic antiparkinson drugs are described in this sec- synaptic dopamine receptors. Levodopa is a precursor sub- tion; names, routes, and dosage ranges are listed in Drugs at stance that is converted to dopamine. Anticholinergic all major symptoms, especially bradykinesia and rigidity. Dopamine cannot be used for replacement therapy because it does not penetrate the blood–brain barrier. Levodopa Indications for Use readily penetrates the CNS and is converted to dopamine by the enzyme amino acid decarboxylase (AADC). The dopamine is Entacapone, levodopa, pergolide, pramipexole, ropinirole, stored in presynaptic dopaminergic neurons and functions like selegiline, and tolcapone are indicated for the treatment of endogenous dopamine. For example, amantadine levodopa has a shorter duration of action and drug effects wear is also used to prevent and treat inﬂuenza A viral infections.
Explore together possible ways to reduce cholesterol and SELECTED REFERENCES fat in the diet buy accutane 30mg amex. Louis: Facts and Explore his supports and provide a list of referrals for long-term Comparisons purchase accutane 20mg free shipping. American Journal of Nursing, forcement for any exercise that he does and together develop a 101(2), 36–43. Dwyer also needs teaching about niacin to prevent un- Williams & Wilkins. New England Journal limit the unpleasant side effects of ﬂushing and pruritus, as can of Medicine, 341, 498–511. Pharmacologic treatment of dyslip- Because niacin is a vitamin, many patients may feel it is safe to idemia. If side effects limit compliance, discuss this cholesterol education program (NCEP) expert panel on detection, evalu- with the prescriber. Many newer, more expensive antilipid agents ation, and treatment of high blood cholesterol in adults (Adult Treatment with fewer side effects can be prescribed to lower cholesterol. Bethesda, MD: National is important to stress the importance of ongoing follow-up for Institutes of Health. OVERVIEW Esophagus The digestive system consists of the alimentary canal (a tube The esophagus is a musculofibrous tube about 10 inches extending from the oral cavity to the anus, approximately 25 (25 cm) long; its main function is to convey food from to 30 feet [7. It secretes a small amount of vary glands, gallbladder, liver, and pancreas). The system also disposes of waste products that result Stomach from the digestive process. The alimentary canal has the same basic structure through- The stomach is a dilated area that serves as a reservoir. The layers of the wall are mucosa, connective tissue, and churns and mixes the food with digestive juices, secretes muscle. Peristalsis propels food through the tract and mixes mucus, hydrochloric acid, and enzymes, starts protein break- the food bolus with digestive juices. Stimulation of the para- down, and secretes intrinsic factor, which is necessary for ab- sympathetic nervous system (by vagus nerves) increases sorption of vitamin B12 from the ileum. The tract has an abundant blood sup- much diffusion of water and electrolytes through the gastric ply, which increases cell regeneration and healing. Blood mucosa in both directions, there is little absorption of these ﬂow increases during digestion and absorption. Carbohydrates and amino acids are also poorly decreases with strenuous exercise, sympathetic nervous sys- absorbed. Only a few highly lipid soluble substances, such as tem stimulation (ie, ﬁght or ﬂight), aging (secondary to de- alcohol and some drugs, are absorbed in moderate quantities creased cardiac output and atherosclerosis), and conditions from the stomach. The stomach normally holds about 1000 mL comfortably and empties in about 4 hours. Numerous fac- ORGANS OF THE DIGESTIVE SYSTEM tors influence the rate of gastric emptying, including the size of the pylorus, gastric motility, type of food, fluidity of Oral Cavity chyme (the material produced by gastric digestion of food), and the state of the duodenum. Factors that cause rapid In the oral cavity, chewing mechanically breaks food into emptying include carbohydrate foods, increased motility, smaller particles, which can be swallowed more easily and fluid chyme, and an empty duodenum. Food is also ties more slowly with decreased gastric tone and motility, mixed with saliva, which lubricates the food bolus for swal- fatty foods, chyme of excessive acidity, and a duodenum lowing and initiates the digestion of starch. The ample blood ﬂow facilitates speciﬁc mone, enterogastrone, that inhibits gastric secretion and hepatic functions, which include the following: motility.
It may cause esophageal or intestinal However purchase accutane 30 mg mastercard, their effectiveness varies and cheap accutane 30mg online, in most cases, there is obstruction if not taken with an adequate amount of water and no scientiﬁc evidence that they work at all. Most supplements may interfere with the absorption of other drugs if taken at for weight loss contain cardiovascular and CNS stimulants that the same time. Adverse effects include nausea, diarrhea, ﬂat- may cause serious, even life-threatening, adverse effects. CHAPTER 30 NUTRITIONAL SUPPORT PRODUCTS AND DRUGS FOR OBESITY 441 Hydroxycitric acid (HCA, found in CitriMax) apparently 2 culate or estimate the BMI; a BMI less than 18. If so, calculate the BMI Laxative and diuretic herbs (eg, aloe, rhubarb root, buck- or use the information in Table 30-5 to estimate the BMI. These products cause a sig- or aggravated by excessive weight, if there is interest in a niﬁcant loss of body ﬂuids, not fat. Adverse effects may in- weight-management program to improve health, and what clude low serum potassium levels, with subsequent cardiac methods, over-the-counter products, or herbal or dietary dysrhythmias and other heart problems. In addition, long-term supplements, if any, have been used to reduce weight. The use of laxatives may lead to loss of normal bowel function and nurse must be very tactful in eliciting information and as- the necessity for continued use (ie, laxative dependency). LipoKinetix, a combination dietary supplement, was re- sessing whether a client would like assistance with weight cently associated with severe hepatotoxicity in 7 young (ages management. If the nurse–client contact stems from a 20 to 32 years), previously healthy people who developed health problem caused or aggravated by excessive weight, acute hepatitis. Five Japan- the client may be more motivated to lose weight and im- ese patients were diagnosed in 1 month or less; two white prove health. Three people • Does the client have symptoms, disease processes, treat- were taking only LipoKinetix; four were also taking other ments, medications, or diagnostic tests that are likely to supplements, which they resumed later without recurrence of interfere with nutrition? The ingredient(s) • Check available reports of laboratory tests, such as serum responsible for the hepatotoxicity was unknown. Nu- tions were considered idiosyncratic, and no other cause of the tritional disorders, as well as many other disorders, may hepatitis was found. With the observation that the ﬁve Japanese developed he- patotoxicity more rapidly than the two Caucasians, there is a Nursing Diagnoses possibility that Asians are less able to metabolize and excrete • Imbalanced Nutrition: Less Than Body Requirements this product. As discussed in the early chapters of this text, related to inadequate intake or impaired ability to digest smaller doses of several prescription drugs are needed in this nutrients population because of genetic or ethnic differences in metab- • Imbalanced Nutrition: More Than Body Requirements olism. This principle may also apply to some herbal and related to excessive intake dietary supplements and should be considered in teaching • Deﬁcient Fluid Volume related to inadequate intake clients of Asian descent. Some specific assessment factors include the fol- Planning/Goals lowing: The client will: • What are usual drinking and eating patterns? Does food intake seem adequate • Improve nutritional status in relation to body needs in terms of normal nutrition? Is the client ﬁnancially able • Maintain ﬂuid and electrolyte balance to purchase sufﬁcient food? What are ﬂuid and food likes • Avoid complications of enteral nutrition, including as- and dislikes? Does the client view nutrition as important in main- • Avoid complications of parenteral nutrition, including taining health? Has there been a re- • Identify the types and amounts of foods to meet nutritional cent change in weight (eg, unintended weight loss)? If needs the client is underweight, assess for contributing factors • Avoid overuse of anorexiant drugs (eg, appetite; ability to obtain, cook, or chew food).
Steroid abusers usually take massive doses and often take several drugs or combine injectable and oral Androgens and anabolic steroids are widely abused in at- drugs for maximum effects purchase accutane 20mg fast delivery. The large doses produce po- tempts to enhance muscle development buy cheap accutane 30mg online, muscle strength, and tentially serious adverse effects in several body tissues: athletic performance. Because of their abuse potential, the • Cardiovascular disorders include hypertension, de- drugs are Schedule III controlled substances. Although non- creased high-density blood lipoproteins (HDL) and prescription sales of the drugs are illegal, they apparently are increased low-density lipoproteins (LDL), all of which easily obtained. Athletes are considered a high-risk group because some • Liver disorders include benign and malignant neo- start taking the drugs in their early teenage years and con- plasms, cholestatic hepatitis and jaundice, and peliosis tinue for years. The number of teens taking anabolic steroids hepatis, a disorder in which blood-ﬁlled cysts develop is thought to be small in comparison with the number using in the liver and may lead to hemorrhage or liver failure. CHAPTER 29 ANDROGENS AND ANABOLIC STEROIDS 427 • Central nervous system disorders include aggression, thetic formulation that is less extensively metabo- hostility, combativeness, and dependence characterized lized by the liver and more suitable for oral admin- by preoccupation with drug use, inability to stop taking istration. They have a rapid onset of action and last cases, psychosis may develop. A topical gel (a 10-g dose • Reproductive system disorders include decreased tes- delivers 100 mg) produces normal serum testosterone ticular function (eg, decreased secretion of endogenous levels within 4 hours after application, and absorption testosterone and decreased formation of sperm), testicu- of testosterone into the blood continues for 24 hours. They include amen- Steady-state serum concentrations occur by the sec- orrhea in women. When the gel is discontinued, • Metabolic disorders include atherosclerosis-promoting serum testosterone levels remain in the normal range changes in cholesterol metabolism and retention of ﬂu- for 24 to 48 hours, but decrease to pretreatment lev- ids, with edema and other imbalances. With Testoderm, the serum trolyte retention contribute to the increased weight testosterone concentration reaches a maximum level associated with drug use. Testoderm must be ap- after the drugs are stopped and may be irreversible. Names plied to the scrotum to achieve adequate blood levels; of anabolic steroids include nandrolone (Deca-Durabolin), scrotal skin is much more permeable to testosterone oxandrolone (Oxandrin), oxymetholone (Anadrol-50), and than other skin areas. Androderm is also applied to nonscrotal skin, and testosterone is continuously absorbed for 24 hours, ANDROGENS AND ANABOLIC with normal blood levels achieved during the ﬁrst day STEROIDS USED AS DRUGS of drug use. Applying the patch at night produces serum testosterone levels similar to those in healthy • When male sex hormones or androgens are given from young men (ie, higher concentrations in the morning exogenous sources for therapeutic purposes, they pro- and lower ones in the evening). These effects include inhibition of endogenous highly bound (98%) to plasma proteins and serum half- sex hormones and sperm formation through negative life varies (eg, 8 days for IM testosterone cypionate, feedback of pituitary luteinizing hormone (LH) and 9 hours for oral ﬂuoxymesterone). About 90% of a dose is • Male sex hormones given to women antagonize or reduce excreted in urine as conjugates of testosterone and its the effects of female sex hormones. It is given orally, has a half-life of 4 to 5 hours, and is lining of the uterus. This characteris- ° Naturally occurring androgens are given by injec- tic limits the clinical usefulness of these drugs in tion because they are metabolized rapidly by the women and children. Some esters of testosterone sexual development may occur if these drugs are given have been modified to slow the rate of metabolism to young children. For example, intramuscu- lar (IM) testosterone cypionate and testosterone enanthate have slow onsets of action and last 2 to Mechanism of Action 4 weeks. As a result, doses as high as 400 mg/day may ported to the nucleus, where it activates ribonucleic and be needed to produce adequate blood levels for full deoxyribonucleic acid production and stimulates cellular syn- replacement therapy.
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