By H. Julio. Willamette University.
Digoxin or a beta blocker may be used for long- close monitoring of drug effects (eg purchase rogaine 5 60 ml on-line mens health zimbabwe, plasma drug levels purchase rogaine 5 60 ml without a prescription prostate 7 price, term management of supraventricular tachydysrhythmias. Propranolol is the beta blocker most commonly used in Amiodarone may be hepatotoxic and cause serious, some- children. It is one of the few antidysrhythmic drugs available times fatal, liver disease. Propranolol has a shorter half-life (3 to elevated without accompanying symptoms of liver impair- 4 hours) in infants than in children older than 1 to 2 years of ment. However, liver enzymes should be monitored regularly, age and adults (6 hours). When given IV, antidysrhythmic especially in clients receiving relatively high maintenance effects are rapid, and clients require careful monitoring for doses. If enzyme levels are above three times the normal bradycardia and hypotension. Esmolol is being used more range or double in a client whose baseline levels were ele- frequently to treat tachydysrhythmias in children, especially vated, dosage reduction or drug discontinuation should be those occurring after surgery. Lidocaine may be used to treat ventricular dysrhythmias Hepatic impairment increases plasma half-life of several precipitated by cardiac surgery or digitalis toxicity. Class I antidysrhythmic drugs, and dosage usually should be re- or III drugs are usually started in a hospital setting, at lower duced. These include disopyramide, flecainide, lidocaine, dosage ranges, because of prodysrhythmic effects. Prodys- mexiletine, moricizine, procainamide, propafenone, quini- rhythmia is more common in children with structural heart dine, and tocainide. In general, serum levels Dosages of adenosine and ibutilide are unlikely to need should be monitored with class IA and IC drugs and IV lido- reductions in clients with hepatic impairment. Class III drugs are used in pediatrics mainly to treat life-threatening refractory tachydysrhythmias. Use in Critical Illness As in adults, most antidysrhythmic drugs and their metabolites are excreted through the kidneys and may accu- Critically ill clients often have multiple cardiovascular and mulate in children with impaired renal function. They may also have refractory dysrhythmias that re- quire strong, potentially toxic antidysrhythmic drugs. Thus, Cardiac dysrhythmias are common in older adults, but in gen- antidysrhythmic drugs are often given IV in critical care eral only those causing symptoms of circulatory impairment settings for rapid reversal of a fast rhythm. Compared IV or oral drugs may be given to prevent recurrence of the with younger adults, older adults are more likely to experi- dysrhythmia. Cautious use is required, and in preventing, recognizing, and treating conditions that predis- dosage usually needs to be reduced to compensate for heart pose to the development of serious dysrhythmias (eg, elec- disease or impaired drug elimination processes. If dysrhythmias cannot be prevented, early recognition and treatment are needed. Overall, any antidysrhythmic drug therapy in critically ill Use in Renal Impairment clients is preferably performed or at least initiated in critical care units or other facilities with appropriate equipment and Antidysrhythmic drug therapy in clients with renal impair- personnel. For example, nurses who work in emergency de- ment should be very cautious, with close monitoring of drug partments or critical care units must be certiﬁed in cardio- effects (eg, plasma drug levels, ECG changes, symptoms that pulmonary resuscitation and advanced cardiac life support may indicate drug toxicity). With ACLS, the American Heart Association and dysrhythmic drugs and their metabolites. As a result, decreased others have developed algorithms to guide drug therapy of renal perfusion or other renal impairment can reduce drug dysrhythmias. As a general rule, dosage of bretylium, digoxin, disopyramide, ﬂecainide, lidocaine, moricizine, pro- Home Care cainamide, propafenone, quinidine, sotalol, and tocainide should be reduced in clients with signiﬁcant impairment of Clients receiving chronic antidysrhythmic drug therapy are renal function. Dosage of adenosine, amiodarone, ibutilide, likely to have signiﬁcant cardiovascular disease. In addition, clients and caregivers should be taught to report symptoms (eg, dizziness or fainting, chest As with renal impairment, antidysrhythmic drug therapy in pain) and avoid over-the-counter drugs unless discussed with clients with hepatic impairment should be very cautious, with a health care provider. CHAPTER 52 ANTIDYSRHYTHMIC DRUGS 771 NURSING Antidysrhythmic Drugs ACTIONS NURSING ACTIONS RATIONALE/EXPLANATION 1. Withhold Bradycardia may indicate impending heart block or cardio- the dose and report to the physician if marked changes are noted vascular collapse.
This ﬂuid generic rogaine 5 60 ml overnight delivery prostate cancer update, called glomerular ﬁltrate generic 60 ml rogaine 5 prostate cancer types, contains the Proximal same components as blood except for blood cells, fats, and tubule proteins that are too large to be ﬁltered. The glomerular ﬁltration rate (GFR) is about 180 L/day, or 125 mL/minute. Most of this ﬂuid is reabsorbed as the glomeru- lar ﬁltrate travels through the tubules. Because ﬁltration is a nonselective process, Collecting the reabsorption and secretion processes determine the com- tubule position of the urine. Once formed, urine ﬂows into collecting tubules, which carry it to the renal pelvis, then through the ureters, bladder, and urethra for elimination from the body. Descending Blood that does not become part of the glomerular fil- limb of loop trate leaves the glomerulus through the efferent arteriole. Peritubular capillaries Tubular Reabsorption Loop of Henle The term reabsorption, in relation to renal function, indicates Figure 56–1 The nephron is the functional unit of the kidney. Increased capillary permeability occurs as part of the occurs in the proximal tubule. Thus, edema may occur acids are reabsorbed; about 80% of water, sodium, potas- with burns and trauma or allergic and inﬂammatory sium, chloride, and most other substances is reabsorbed. In the descending limb of the loop of Henle, water from a sequence of events in which increased is reabsorbed; in the ascending limb, sodium is reabsorbed. This is the primary mechanism for marily by the exchange of sodium ions for potassium ions edema formation in heart failure, pulmonary edema, secreted by epithelial cells of tubular walls. The remaining water and solutes are now appropri- with decreased synthesis of plasma proteins (caused ately called urine. This conserves water important in keeping fluids within the blood- needed by the body and produces more concentrated urine. When plasma proteins are lacking, fluid Aldosterone, a hormone from the adrenal cortex, promotes seeps through the capillaries and accumulates in sodium–potassium exchange mainly in the distal tubule and tissues. If severe, edema Tubular Secretion may distort body features, impair movement, and inter- fere with activities of daily living. Specific manifestations of edema are determined by movement of substances from blood in the peritubular cap- its location and extent. A common type of localized illaries to glomerular filtrate flowing through the renal edema occurs in the feet and ankles (dependent tubules. Secretion occurs in the proximal and distal tubules, edema), especially with prolonged sitting or standing. In the proxi- A less common but more severe type of localized mal tubule, uric acid, creatinine, hydrogen ions, and am- edema is pulmonary edema, a life-threatening condi- monia are secreted; in the distal tubule, potassium ions, tion that occurs with circulatory overload (eg, of in- hydrogen ions, and ammonia are secreted. Secretion of travenous [IV] fluids or blood transfusions) or acute hydrogen ions is important in maintaining acid–base balance heart failure. ALTERATIONS IN RENAL FUNCTION DIURETIC DRUGS Many clinical conditions alter renal function. In some condi- tions, excessive amounts of substances (eg, sodium and water) Diuretic drugs act on the kidneys to decrease reabsorption of are retained; in others, needed substances (eg, potassium, pro- sodium, chloride, water, and other substances. These conditions include cardiovascu- classes are the thiazides and related diuretics, loop diuretics, lar, renal, hepatic, and other disorders that may be managed and potassium-sparing diuretics, which act at different sites with diuretic drugs. Major clinical indications for diuretics are edema, heart Edema failure, and hypertension. In edematous states, diuretics mo- bilize tissue fluids by decreasing plasma volume. Additional characteristics include the usually attributed to sodium depletion. Initially, diuretics following: decrease blood volume and cardiac output. Edema formation results from one or more of the fol- use, cardiac output returns to normal, but there is a persis- lowing mechanisms that allow ﬂuid to leave the blood- tent decrease in plasma volume and peripheral vascular re- stream (intravascular compartment) and enter interstitial sistance.
Some re- ceptors act rapidly to open ion channels; others interact with SYNAPSE a variety of intracellular proteins to initiate a second messen- Presynaptic Postsynaptic ger system discount 60 ml rogaine 5 with amex man health in hindi. For example buy discount rogaine 5 60 ml online mens health 5 day workout routine, when norepinephrine binds with nerve terminal Release nerve terminal alpha- or beta-adrenergic receptors, intracellular events in- site clude activation of the enzyme adenyl cyclase and the pro- duction of cyclic adenosine monophosphate (cAMP). In this Receptor sites case, the cAMP is a second messenger that activates cellular functions and the physiologic responses controlled by the Neurotransmitters alpha- and beta-adrenergic receptors. A neurotransmitter– receptor complex may have an excitatory or inhibitory effect on the postsynaptic neuron. Receptors increase in number and activity (up-regulation) when there is underactivity at the synapse. They decrease in number and activity (down-regulation) when there is over- Presynaptic nerve Postsynaptic nerve activity. Like other protein molecules in the body, receptors cell membrane cell membrane are constantly being synthesized and degraded. More specif- Figure 5–1 Neurotransmission in the central nervous system. Neu- ically, it is believed that receptor proteins are constantly being rotransmitter molecules (eg, norepinephrine and acetylcholine), re- leased by the presynaptic nerve, cross the synapse and bind with formed by the endoplasmic reticulum–Golgi apparatus and in- receptor proteins in the cell membrane of the postsynaptic nerve. If the 74 SECTION 2 DRUGS AFFECTING THE CENTRAL NERVOUS SYSTEM synapses are overused and excessive amounts of neurotrans- Two groups of dopamine receptors have been identiﬁed. Thus, synaptic fatigue receptors, which activate adenyl cyclase to produce cAMP. D2 recep- control mechanisms of the nervous system to readjust abnor- tors have been described most thoroughly; they are thought mally stimulated or depressed nerve function toward normal. D3 and D4 receptor functions have not Neurotransmission Systems been delineated. Overall, dopamine actions at the cellular level depend on the subtype of receptor to which it binds and Neurons function through communication networks that the simultaneous effects of other neurotransmitters at the may be called neurotransmission systems, the major elements same target neurons. The GABA-ergic system uses GABA as its neurotrans- Although neurotransmitters, synapses, and receptors are dis- mitter. It is the major inhibitory neurotransmitter in the and mental processes. Although many details of neuronal func- CNS, with a role in many neuronal circuits (estimated at tion remain elusive, a great deal of knowledge has been gained. GABA receptors have For example, numerous neurotransmitters and subtypes of been divided into two main types, A and B. Major ceptor is a chloride ion channel that opens when GABA is neurotransmission systems are the cholinergic, dopaminergic, released from presynaptic neurons. GABAB has not been GABA-ergic, noradrenergic, and serotonergic networks. Acetylcholine, the ﬁrst substance to be desig- of multiple subtypes of GABA receptors and important nated as a neurotransmitter in the CNS, is located in many functional differences among them. It is also a neurotransmitter neurotransmitter and extends to virtually every area of the in the autonomic nervous system and at peripheral neuro- brain. Like dopamine, norepinephrine is a catecholamine syn- muscular junctions. It is found in relatively large amounts synapses and nerve–muscle junctions and inhibitory effects in the hypothalamus and the limbic system and in smaller at some peripheral sites, such as organs supplied by the vagus amounts in most areas of the brain, including the reticular nerve. Norepinephrine is mainly an excitatory neuro- arousal, memory, motor conditioning, and speech. Dopamine is derived from tyrosine, an amino inhibitory receptors at some nerve synapses. Dopamine makes up more nervous system, are divided into alpha- and beta-adrenergic than half the catecholamine content in the brain and is receptors and their subtypes. Activation of alpha1, beta1, and found in the substantia nigra, the midbrain, and the hypo- beta2 receptors is thought to stimulate activity of intracellular thalamus, with high concentrations in the substantia nigra adenyl cyclase and the production of cAMP. Much of the information about dopamine alpha2 receptors is associated with inhibition of adenyl cyclase is derived from studies of antipsychotic drugs (see Chap. These effects on ion channels may increase In the CNS, dopamine is thought to be inhibitory in the membrane resistance to stimuli and inhibit the ﬁring of CNS basal ganglia but may be excitatory in other areas.
The most common design type is over the needle; the needle • Use veins with a large blood volume ﬂowing through them is used to start the IV 60 ml rogaine 5 prostate cancer psa 0, then it is removed buy rogaine 5 60 ml without prescription mens health 50. Many drugs cause irritation and phlebitis in catheter to start an IV, one that is much smaller than the small veins. Reasons include the difﬁculty of sta- patient, drug, dosage, date, time of mixing, expiration date, bilizing and maintaining an IV line at these sites. The of several IV set-ups, including a scalp–vein needle and tubing, risks of serious or fatal complications are too high. When it is necessary to change and functioning properly (eg, catheter not clotted, IV ﬂuid not an IV site, use the opposite arm if possible. If leak- Drug Preparation age occurs, some drugs are very irritating to subcutaneous tis- Most IV drugs are prepared for administration in pharmacies and sues and may cause tissue necrosis. When a nurse must prepare a medication, • Maintain sterility of all IV ﬂuids, tubings, injection sites, drug considerations include the following. Other formulations contain various substances that the bloodstream, breaks in sterile technique can lead to serious are not sterile, pure enough, or soluble enough to be in- systemic infections (septicemia) and death. In recent years, there have been • When two or more medications are to be given one after the numerous reports of medication errors resulting from IV other, ﬂush the IV tubing and catheter (with the infusing IV ﬂuid administration of drug preparations intended for oral use!! After irriga- should have a blunt tip that will not connect to or penetrate tion, heparin then needs to be reinstilled. Most drugs given by IV push (direct diluted prior to IV administration and powdered medications injection) can be given over 2–5 minutes and most drugs diluted must be reconstituted appropriately (eg, the correct amount in 50–100 mL of IV ﬂuid can be infused in 30–60 minutes. In addition, be sure potassium or magnesium), be sure the medications are compati- any reconstituted drug is completely dissolved to avoid par- ble with the other substances. Consult compatibility charts (usu- ticles that may be injected into the systemic circulation and ally available on nursing units) or pharmacists when indicated. A ﬁltered aspira- • IV ﬂow rates are usually calculated in mL/hour and drops per tion needle should be used when withdrawing medication minute. Required information includes the amount of solution or from a vial or ampule, to remove any particles in the solu- medication to be infused, the time or duration of the infusion, and tion. The ﬁlter needle should then be discarded, to prevent the drop factor of the IV administration set to be used. The drop ﬁltered particles from being injected when the medication is factor of macrodrip sets may be 10, 15, or 20 drops per milliliter, added to the IV ﬂuid. The drop factor of all microdrip sets is • Check the expiration date on all IV medications. Following is a sample calculation: have a limited period of stability after they are reconstituted Order: Cefazolin 1 g IV q8h or diluted for IV administration. Most are compatible with 5% dextrose in water or Solution: Divide 100 by 60 to determine mL/min (1. CHAPTER 3 ADMINISTERING MEDICATIONS 39 In many settings, needleless systems are being used. These Nursing Notes: Apply Your Knowledge involve a plastic tip on the syringe that can be used to enter vials and injection sites on IV tubing. Needleless systems were developed Your client has a nasogastric feeding tube in place. You will be ad- ministering morning medications, including 4 tablets, 1 capsule, because of the risk of injury and spread of blood-borne and 10 cc of an elixir. Describe how you will safely administer pathogens, such as the viruses that cause acquired immuno- medications through a feeding tube to this client. When vials or ampules contain a powder able with or without an attached needle. Syringes are calibrated form of the drug, a sterile solution of water or 0. However, the chloride must be added and the drug dissolved before with- calibrations vary according to the size and type of syringe. Use a ﬁlter needle to withdraw the medication from Insulin and tuberculin syringes are used for specific an ampule or vial because broken glass or rubber fragments purposes.
But also look at some of the shorter features in the weekend supplements: these may be competent rather than brilliant generic 60 ml rogaine 5 with visa prostate quercetin, but they have been published generic rogaine 5 60 ml otc prostate zoloft. Writing is a perishable commodity, and writers should be satisfied when they have a plausible idea, supported by reasonable evidence, presented in good faith (see scientific papers). Typefaces A lot of people have strong views about which typeface to use, but the current consensus is that, provided you use a familiar type, the type of type will be less important than the size of type you use (see monologophobia). Never reduce your typeface in order to fit in all the words; cut the words out instead. UK-US English This can be a major problem, though it is an area where people may find it easier to adapt if one of the Englishes is not their first language. I have so far been unable to find a simple book that will guide readers through all the pitfalls, but here are some useful pointers. There are several groups of differ- ences, mainly concerning the US English preference for fewer vowels. The endings –ise and –ize seem fairly interchangeable (though the US, the Oxford English Dictionary and the housestyle of the publishers of this book favour the -ize). Nowadays of course the problem is much less than it used to be, because your computer program (stet), if handled with sufficient knowledge and tact, will automatically point out when your spelling wanders over to the wrong side of the Atlantic. A dresser in the UK is where you put your china, in the US it is where you put your underwear. The spread of US programs on computers means that some of these practices are spreading, whether we like it or not, throughout the UK and the rest of the world. It also comes from a feeling that Americans are more verbose and less Anglo-Saxon. This should not give major problems to those writing for interna- tional journals. If you have worked out in advance where you are to publish your article (see brief setting), then this becomes one of a number of specifications that you can meet without too much trouble. Do not get obsessed by it: this is not a test of international cross- dressing. Beware the occasional pitfall – my American wife worried for weeks because I had proposed building a dresser in the kitchen. Uncommon words You may feel that sprinkling your writing with these sends a signal that you are learned and cultivated. If you use uncommon words sparingly (one per item of writing), people may be fooled into thinking that you are clever; if you use more they will consider you pompous and may well stop reading (see post spelling bee traumatic disorder). Unpublishable articles Unfortunately some people feel that working long enough on a piece of text will increase its chances of being published (see Icarus fallacy). This is not true, and we can usually identify articles that stand little chance of being published before we start writing them (see brief setting). Unpublished articles Too many people leave lying around in bottom drawers articles that could be published if only they could just summon up that extra burst of energy. Take out the article, go back to the first stage of writing (brief setting), match it to another market, and have another go. Up-to-date We should commit to print the latest informa- tion we have to hand. Some people use this as an excuse for not parting with the final version. Whatever the cause, the first group of editors met informally in Vancouver in 1978 and now, under the formal name of the International Committee of Medical Journal Editors, they meet every year. One of their major activities is producing the Uniform requirements for manuscripts submitted to biomedical journals, now in its fifth edition. These set up common guidelines for submitting to journals – all of the 500 participating journals will consider all manuscripts that conform to this common style. The group has also issued a number of statements on layout of references, and on contentious matters, such as redundant or duplicate publication, definition of a peer- reviewed journal, editorial freedom and integrity, conflict of interest, and confidentiality. They are useful statements, and copies of the guidelines, which include the statements, can usually be obtained via a participating journal. Their main value is that they show clearly how editors think on all kinds of matters, from the setting out of references to the function of each section of a scientific paper.
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