By G. Umbrak. State University of New York at Oswego. 2018.
Carbenicillin is available as an oral formulation inated by the kidneys discount reminyl 4 mg line treatment 001 - b. The other drugs are usually given by intermittent IV infusion cheap reminyl 4 mg amex symptoms inner ear infection, although most can be given IM. First-Generation Cephalosporins Penicillin/Beta-Lactamase The first cephalosporin, cephalothin, is no longer available Inhibitor Combinations for clinical use. However, it is used for determining sus- ceptibility to first-generation cephalosporins, which have Beta-lactamase inhibitors are drugs with a beta-lactam struc- essentially the same spectrum of antimicrobial activity. They bind and inactivate These drugs are effective against streptococci, staphylo- the beta-lactamase enzymes produced by many bacteria cocci (except methicillin-resistant S. When combined with a penicillin, the beta- species, Corynebacterium diphtheriae, Proteus mirabilis, lactamase inhibitor protects the penicillin from destruction by and Bacteroides species (except Bacteroides fragilis). Clavulanate, sulbactam, and tazo- bactam are the beta-lactamase inhibitors available in combi- Second-Generation Cephalosporins nations with penicillins. Unasyn is a combination of ampicillin and sulbactam Second-generation cephalosporins are more active against available in vials with 1 g of ampicillin and 0. Thus, they may be effective in infections resistant to contains amoxicillin and clavulanate. It is available in 250-, 500-, and 875-mg tablets, each of which contains 125 mg of other antibiotics, including infections caused by Hemophilus clavulanate. Thus, two 250-mg tablets are not equivalent to inﬂuenzae, and Klebsiella species, E. Because each of these drugs has a different anti- and clavulanate in an IV formulation containing 3 g ticar- microbial spectrum, susceptibility tests must be performed cillin and 100 mg clavulanate. Zosyn is a combination of for each drug rather than for the entire group, as may be done piperacillin and tazobactam in an IV formulation. Cefoxitin (Mefoxin), for example, dosage strengths are available, with 2 g piperacillin and 0. Third-Generation Cephalosporins CEPHALOSPORINS Third-generation cephalosporins further extend the spec- Cephalosporins are a widely used group of drugs that are de- trum of activity against gram-negative organisms. Although technically cefoxitin and ce- to activity against the usual enteric pathogens (eg, E. Cephalosporins are broad-spectrum agents in infections caused by unusual strains of enteric organisms with activity against both gram-positive and gram-negative such as Citrobacter, Serratia, and Providencia. Compared with penicillins, they are in general less ference is that third-generation cephalosporins penetrate active against gram-positive organisms but more active against inﬂamed meninges to reach therapeutic concentrations in CSF. Thus, they may be useful in meningeal infections caused by Once absorbed, cephalosporins are widely distributed into common pathogens, including H. Many cephalosporins do not reach drugs are active against Pseudomonas organisms, drug-resis- therapeutic levels in CSF; exceptions are cefuroxime, a second- tant strains may emerge when a cephalosporin is used alone for generation drug, and the third-generation agents. Most Overall, cephalosporins gain gram-negative activity and cephalosporins are excreted through the kidneys. Exceptions lose gram-positive activity as they move from the first to 518 SECTION 6 DRUGS USED TO TREAT INFECTIONS the third generation. The second- and third-generation drugs CARBAPENEMS are more active against gram-negative organisms because they are more resistant to the beta-lactamase enzymes Carbapenems are broad-spectrum, bactericidal, beta-lactam (cephalosporinases) produced by some bacteria to inacti- antimicrobials. Imipenem/cilastatin (Primaxin) is given parenterally and Fourth-Generation Cephalosporins distributed in most body ﬂuids. Imipenem is rapidly broken down by an enzyme (dehydropeptidase) in renal tubules and Fourth-generation cephalosporins have a greater spectrum of therefore reaches only low concentrations in urine. Cilastatin antimicrobial activity and greater stability against breakdown was synthesized to inhibit the enzyme and reduce potential by beta-lactamase enzymes compared with third-generation renal toxicity of the antibacterial agent. Cefepime is the ﬁrst fourth-generation cephalosporin indicate the amount of imipenem; the solution contains an to be developed. It is active against both gram-positive and equivalent amount of cilastatin. With gram-positive organisms, it The drug is effective in infections caused by a wide range is active against streptococci and staphylococci (except for of bacteria, including penicillinase-producing staphylococci, methicillin-resistant staphylococci). Its main in- similar to that of ceftazidime and its activity against Entero- dication for use is treatment of infections caused by organisms bacteriaceae is greater than that of third-generation ceph- resistant to other drugs. Moreover, cefepime retains activity against strains of other beta-lactam antibiotics, including the risk of cross- of Enterobacteriaceae and P.
Themajorityofhumanprimaryendingsrespond dominantly for spindles in the contracting muscle buy discount reminyl 4 mg on-line medicine 003. It vigorously to tendon vibration buy discount reminyl 8 mg medicine escitalopram, though often at sub- hasalimitedroleincompensatingformusclefatigue. Most cutaneous (iii) The efﬁcacy of drive in activating spindle mechanoreceptors respond to vibration, and it is endings depends on whether the contraction pro- probable that Rufﬁni endings in joints do so as well. Shortening Like any mechanical stimulus, vibration of a tendon (asinaconcentriccontraction)unloadsspindleend- will spread widely through bone, exciting receptors ings,andanincreaseinspindledischargeoccursonly in skin, muscles, fascia and joints remote from the inslowcontractionsorwhengreatereffortisrequired site of vibration. There will probably drive can enhance the spindle response to vibration, be little increase in spindle feedback from the con- butthecontractionitselfmayunloadtheendingand tracting muscle in unloaded rapid shortening move- thereby decrease the spindle discharge. Stretching a con- tracting muscle (an eccentric contraction) greatly Motor tasks and physiological enhances any fusimotor effect on spindle discharge. Performance of the Jendrassik manoeuvre poten- (iv) The exact role of the fusimotor system in nor- tiates tendon jerks in uninvolved non-contracting mal motor control remains speculative. However, it muscles, but there is now cogent evidence that this is possible that the -driven feedback from muscle is not due to widespread activation of d motoneu- spindles plays an important role in learning motor rones. References 145 Changes in fusimotor activity in patients REFERENCES There are cogent arguments against the view that Al-Falahe,N. Roleofthehumanfusimo- fusimotor dysfunction drives motor disturbances, torsysteminamotoradaptationtask. JournalofPhysiology but the database of spindle recordings from patients (London), 401, 77–95. Response proﬁles of human muscle afferents during active ﬁnger movements. Reﬂex changes for spindle afferents from triceps surae and the fore- inmusclespindledischargeduringavoluntarycontraction. Reﬂexactivationofmusclespindlesinhuman independent of the level of drive. Behavior of human muscle receptors when reliant activation drives the next clonic contraction. Journal of suggests that spinal proprioceptive reﬂexes do not Neurophysiology, 64, 661–70. Muscle spindle feedback during spa- There are, as yet, no published reports of recordings tially oriented movements. Experimental Brain Research, from spindle endings in patients with spinal spas- 134, 301–10. Journal of Physiology (London), 180, group II muscle afferents, contributes to the reﬂex 649–72. Afferent tobedominatedbymusclespindleactivityandsome andefferentactivationofhumanmusclereceptorsinvolved single-unit recordings during parkinsonian tremor. Experimental Neurol- These have revealed no evidence of selective or dis- ogy, 41, 754–68. JournalofNeurology,Neurosurgery but the question needs to be addressed quantita- and Psychiatry, 37, 1012–21. The activity of human muscle spindle endings ings from identiﬁed afferents. In International Review of Phys- ing tremor, spindle discharge occurs in two phases: iology,vol. Criticalexaminationofthecasefororagainstfusimo- stretched, a pattern similar to that seen with volun- tor involvement in disorders of muscle tone. The responses of human muscle spindle endings to ism of monosynaptic reﬂex reinforcement during Jendras- vibration during isometric contraction. Scandinavian Journal of soleus Ia afferents to vibration in the presence of the tonic Rehabilitation Medicine, 9, 15–23. JournalofPhysiology(London),276, of movement in a man without large myelinated sensory 159–64.
Symptoms of myocardial ischemia occur when the myocardium does not get an adequate supply of oxy- genated blood order reminyl 8 mg with amex medications ok during pregnancy. Symptoms of congestive heart failure occur when the increased cardiac workload is prolonged buy 8 mg reminyl otc symptoms breast cancer. Cardiovascular prob- lems are more likely to occur in clients who are elderly or who al- ready have heart disease. With propylthiouracil and methimazole, observe for: (1) Hypothyroidism—bradycardia, congestive heart fail- ure, anemia, coronary artery and peripheral vascular dis- ease, slow speech and movements, emotional and mental dullness, excessive sleeping, weight gain, constipation, skin changes, and others (2) Blood disorders—leukopenia, agranulocytosis, hypo- Leukopenia may be difﬁcult to evaluate because it may occur with prothrombinemia hyperthyroidism and with antithyroid drugs. Agranulocytosis oc- curs rarely but is the most severe adverse reaction; the earliest symptoms are likely to be sore throat and fever. With iodine preparations, observe for: Adverse effects are uncommon with short-term use. Drugs that increase effects of thyroid hormones: (1) Activating antidepressants (eg, bupropian, venlafaxine), These drugs may cause CNS and cardiovascular stimulation when adrenergic antiasthmatic drugs (eg, albuterol, epinephrine), taken alone. When combined with thyroid hormones, excessive nasal decongestants cardiovascular stimulation may occur and cause myocardial ischemia, cardiac dysrhythmias, hypertension, and other adverse cardiovascular effects. Excessive CNS stimulation may produce anxiety, nervousness, hyperactivity, and insomnia. Drugs that decrease effects of thyroid hormones: (1) Antacids, cholestyramine, iron, sucralfate Decrease absorption of levothyroxine; give levothyroxine 2 hours before or 4 to 6 hours after one of these drugs (2) Antihypertensives Decrease cardiac stimulating effects (3) Estrogens, including oral contraceptives containing Estrogens increase thyroxine-binding globulin, thereby increasing estrogens the amount of bound, inactive levothyroxine in clients with hypo- thyroidism. This decreased effect does not occur in clients with adequate thyroid hormone secretion because the increased binding is offset by increased T4 production. Women taking oral contra- ceptives may need larger doses of thyroid hormone replacement than would otherwise be needed. It is used in hyperthyroidism to reduce tachycardia and other symptoms of excessive cardiovascular stimulation. Drug that increases effects of antithyroid drugs: (1) Lithium Acts synergistically to produce hypothyroidism CHAPTER 25 THYROID AND ANTITHYROID DRUGS 365 5. What is the drug of first choice for treating hypo- Nursing Notes: Apply Your Knowledge thyroidism? What are adverse effects of drug therapy for hypo- Answer: For most drugs, substituting generic brands is safe and thyroidism? What signs and symptoms are associated with hyper- absorbed into the bloodstream) differs for generic brands. Sanchez is ex- periencing signs of hypothyroidism because her blood levels 8. Which drugs reduce blood levels of thyroid hormone in have fallen below the therapeutic range since she started taking hyperthyroidism, and how do they act? What are adverse effects of drug therapy for hyper- generic drugs may be offset by the higher dose required to thyroidism? When propranolol is used in the treatment of hyper- thyroidism, what are its expected effects? What is the effect of thyroid disorders on metabolism of How Can You Avoid This Medication Error? Answer: To convert from milligrams to micrograms, use the con- version factor of 1 mg = 1000 mcg. What signs and symptoms are associated with hypo- of altered health states, 6th ed. Identify clients at risk for development of hyper- calcitonin, and vitamin D in regulating calcium calcemia. Identify populations at risk for development of calcemia as a medical emergency. Discuss prevention and treatment of hypo- supplements, calcitonin, and bisphosphonate calcemia and osteoporosis. Critical Thinking Scenario You are working at a community center, providing health promotion and disease prevention programs for older adults who live independently in the community. How medication classes, such as bisphosphonates and selective estrogen receptor modulators, work to prevent osteoporosis in high-risk people. OVERVIEW mones, calcium, phosphorus, bone metabolism, and selected disorders are described. Calcium and bone metabolism are regulated by three hor- mones: parathyroid hormone (PTH), calcitonin, and vitamin D, which act to maintain normal serum levels of calcium. Parathyroid Hormone When serum calcium levels are decreased, hormonal mecha- nisms are activated to raise them; when they are elevated, Parathyroid hormone secretion is stimulated by low serum mechanisms act to lower them (Fig.
The combina- duces the aldosterone-induced retention of sodium and water and tion has similar effects to those of an ACE inhibitor or an ARB reminyl 8mg without a prescription treatment jaundice, impaired vascular function discount 4 mg reminyl fast delivery medications jfk was on. Although ACE inhibitors also decrease but may not be as well tolerated by clients. Spironolactone is given in Chapter 53; hydralazine and other vasodilators are discussed in a daily dose of 12. In clients with Oral vasodilators usually are used in clients with chronic HF adequate renal function (ie, serum creatinine 2. Overall, studies indicate that the at low doses, titrated to desired hemodynamic effects, and dis- addition of spironolactone improves cardiac function and reduces continued slowly to avoid rebound vasoconstriction. Vasodilators Vasodilators are essential components of treatment regimens for HF, and the beneﬁcial effects of ACE inhibitors and angiotensin Drugs at a Glance: Drugs for Heart Failure Routes and Dosage Ranges Generic/Trade Name Adults Children Inotropic Agents CARDIAC GLYCOSIDE Digoxin (Lanoxin) Digitalizing dose, PO 0. Maintenance dose, PO, IV, approximately 20–35% of the digitalizing dose Newborns: Digitalizing dose, PO 0. Maintenance dose, PO, IV, approximately 20–35% of the digitalizing dose. IV infusion (maintenance dose), 10 mg/kg/d 3–5 mcg/kg/min Milrinone (Primacor) IV bolus infusion (loading dose), 50 mcg/kg over 10 min. HUMAN NATRIURETIC PEPTIDE B-TYPE Nesiritide (Natrecor) IV bolus infusion (loading dose), 2 mcg/kg followed by Safety not established continuous infusion of 0. CHAPTER 51 DRUG THERAPY OF HEART FAILURE 747 Two new classiﬁcations of drugs, human natriuretic peptides not prolong survival. In HF, it is given concomitantly with a and endothelin receptor antagonists, are also presented. In atrial dysrhythmias, digoxin slows the rate of ventricular contraction (negative chronotropic effect). Negative chro- Digoxin notropic effects are probably caused by several factors. First, digoxin has a direct depressant effect on cardiac conduction Digoxin (Lanoxin) is the only commonly used digitalis gly- tissues, especially the atrioventricular node. In the following discussion, the terms digitalization creases the number of electrical impulses allowed to reach the and digitalis toxicity refer to digoxin. Third, increased efﬁciency of myocardial contraction and vagal stimulation decrease com- General Characteristics pensatory tachycardia that results from the sympathetic ner- When digoxin is given orally, absorption varies among avail- vous system response to inadequate circulation. Lanoxicaps, which are liquid-ﬁlled cap- sules, and the elixir used for children are better absorbed than Indications for Use tablets. With tablets, the most frequently used formulation, differences in bioavailability are important because a person The clinical uses of digoxin are management of HF, atrial ﬁb- who is stabilized on one formulation may be underdosed or rillation, and atrial ﬂutter. Digoxin may be used in acute or overdosed if another formulation is taken. Differences are at- chronic conditions, for digitalization, or for maintenance tributed to the rate and extent of tablet dissolution rather than therapy. In addition to drug dosage forms, other factors that may decrease digoxin absorption include the Contraindications to Use presence of food in the GI tract, delayed gastric emptying, malabsorption syndromes, and concurrent administration of Digoxin is contraindicated in severe myocarditis, ventricu- some drugs (eg, antacids, cholestyramine). It also crosses the placenta, and serum lev- syndrome (risk of fatal dysrhythmias), electrolyte imbal- els in neonates are similar to those in the mother. Digoxin cir- ances (hypokalemia, hypomagnesemia, hypercalcemia), and culates mainly in a free state, with only 20% to 30% bound renal impairment. How- Administration and Digitalization ever, toxicity may occur at virtually any serum level. Most (60% to 70%) of the digoxin is excreted unchanged Digoxin is given orally or intravenously (IV). Dosage must be reduced in the presence of be given intramuscularly, this route is not recommended be- renal failure to prevent drug accumulation and toxicity. When given orally, onset of action occurs in 30 minutes to 2 hours, and peak effects occur in approximately 6 hours. Mechanisms of Action When given IV, the onset of action occurs within 10 to 30 minutes, and peak effects occur in 1 to 5 hours. In HF, digoxin exerts a cardiotonic or positive inotropic effect In the heart, maximum drug effect occurs when a steady- that improves the pumping ability of the heart.