By Z. Curtis. State University of New York College at Purchase. 2018.
Broken lines indicate 50% of maximum However 15mcg mircette, in contrast to intrinsic activity purchase mircette 15 mcg without a prescription, no numerical response (horizontal) and individual ED50 values (vertical) 15 mcg mircette with visa. However mircette 15mcg mastercard, the fact that the The mathematical relationship of response to effi- dose–response curve for drug a lies to the left of the cacy and affinity is the following: curve for drug b indicates that drug a is more potent, that is, less of drug a is needed to produce a given re- EA e[A] f sponse. In contrast, drug c has less maxi- This equation states that the ratio of the response (EA) mum effect than either drug a or drug b. Drug c is said to a given concentration of an agonist to the maximum to have a lower intrinsic activity than the other two. KA is the reciprocal of the affinity constant and, un- ever, is the same as that of drug b, because both drugs der equilibrium conditions, have the same ED50(3 g /kg). The ED50is the dose pro- ducing a response that is one-half of the maximal re- [R][A] KA sponse to that same drug. Such factors as the Although the details are beyond the scope of this text- severity and frequency of undesirable effects associated book, it should be noted that by the use of combinations with each drug and their cost to the patient are more of agonists and antagonists, dose–response curves, and relevant factors in the choice between two similar mathematical relationships, it is possible to estimate the drugs. EQUATIONS DERIVED FROM DRUG–RECEPTOR INTERACTIONS It is important not to confuse the term potency with DRUG ANTAGONISM affinity or the term intrinsic activity with efficacy. The The terms agonist and antagonist have already been in- constants that relate an agonist A and its receptor R to troduced. The several types of antagonism can be classi- the response may be represented as follows: fied as follows: k1 k3 1. Noncompetitive antagonism Chemical Antagonism Chemical antagonism involves a direct chemical interac- tion between the agonist and antagonist in such a way as Dose of Agonist (geometric scale) to render the agonist pharmacologically inactive. Chelation involves a particular type of absence (a) and the presence (b, c, d) of increasing doses two-pronged attachment of the antagonist to a metal of an equilibrium-competitive antagonist. One chemical chelator, dimercaprol, is used in the treatment of toxicity from mercury, arsenic, and gold. After complexing with the dimercaprol, mer- cury is biologically inactive and the complex is excreted creased. The curves are parallel, and the maximum ef- Functional antagonism is a term used to represent the fects are equal. The antagonist has shifted the dose– interaction of two agonists that act independently of response curve of the agonist to the right. Thus, response is still possible, but greater amounts of the ag- indirectly, each tends to cancel out or reduce the effect onist are required. A classic example is acetylcholine and epi- creased, the dose–response curve is shifted farther to nephrine. These agonists have opposite effects on sev- the right (curve c), still with no decrease in the maxi- eral body functions. Acetylcholine stimulates onist required to achieve maximum response is greater intestinal movement, and epinephrine inhibits it. Acetylcholine constricts the pupil, and epinephrine di- Examples of equilibrium-competitive antagonists are lates it; and so on. Of course, this continual shift of the curve to the right with no change in maximum as the dose of antag- Competitive Antagonism onist is increased assumes that very large amounts of Competitive antagonism is the most frequently encoun- the agonist can be achieved in the biophase. The erally true when the agonist is a drug being added from antagonist combines with the same site on the receptor as outside the biological system. However, if the agonist is does the agonist, but unlike the agonist, does not induce a naturally occurring substance released from within a response; that is, the antagonist has little or no efficacy. Competitive antagonists can fall creasing the amount of antagonist ultimately abolishes into either of two subtypes, depending on the type of all response. The effect of a nonequilibrium antagonist on the If the bond is a loose one, the antagonism is called equi- dose–response curve of an agonist is quite different librium competitive or reversibly competitive. If the from the effect of an equilibrium antagonist, as illus- bond is covalent, however, the combination of the an- trated in Figure 2. As the dose of nonequilibrium an- tagonist with the receptor is not readily reversible, and tagonist is increased, the slope of the agonist curve and the antagonism is termed nonequilibrium competitive or the maximum response achieved are progressively de- irreversibly competitive. When the amount of antagonist is adequate If the antagonism is of the equilibrium type, the an- (curve d), no amount of agonist can produce any re- tagonism increases as the concentration of the antago- sponse. Conversely, the antagonism can be over- mine, which form covalent bonds with receptors, are ex- come (surmounted) if the concentration of the agonist amples of nonequilibrium-competitive antagonists (see in the biophase (the region of the receptors) is in- Chapter 11).
Once you are sure that fluid status is optimal and urine output is still suboptimal cheap mircette 15 mcg mastercard, use low-dose dopamine (2–5 mg/kg/min) to dilate the renal vessels discount 15 mcg mircette with amex. If the patient is fluid-overloaded discount 15 mcg mircette, use furosemide in increasing doses to diurese fluid generic mircette 15mcg on line. Check the Foley catheter for patency, replacing it immediately if there is any question. Decompression of the upper urinary tracts may require stents or percutaneous drainage. Stress Ulceration The development of stress ulceration in the ICU patient is a serious complication. The pathophysiology is related to diminished blood flow to the viscera in stress situations, leading to alterations in the mucosal barrier to the effects of gastric acid. Prophylaxis • Routine cardiovascular support of perfusion • Routine use of H2 blockers (Pepcid, etc) • Antacid administration (eg, Maalox 30 mL per NG tube q2h). In patients with renal failure, use aluminum hydroxide, avoid magnesium-containing antacids • Enteral feedings, when tolerated, remain a good method to neutralize gastric acid. A clearly visible lesion (bleeding vessel) warrants operative intervention, but diffuse gastritis is best treated initially with aggressive antacid and H2 blocker therapy. First and foremost in the treatment of this potentially fatal condition is to remain vigilant for its development in the critically ill patient. Presenting signs are similar to those in healthy patients with cholecystitis and include right upper quadrant pain, fever, leukocytosis, and elevated liver chemistries (especially bilirubin or alkaline phosphatase). Treatment is surgical (cholecystectomy), and should be done as early as possible to avoid perforation. Nutrition The nutritional needs of the critically ill patient are of major significance in overall patient care. The details of TPN, or hyperalimentation, as well as enteral feedings are covered in Chapters 11 and 12. If you do not think the critically ill patient can take nutrition for 5 days because of postoperative ileus, intubation, etc, be sure to start nutritional support by the fifth day. Enteral nutrition (eg, oral, NG tube, jejunostomy tube) should be used in all patients with a functioning intestinal tract. Disseminated Intravascular Coagulation DIC is a complex management problem that often presents in the critically ill patient. This clinical syndrome may accompany a number of disease states, including shock syndromes, sepsis, malignancy, and some obstetric conditions. As with many of the pathologic condi- tions that accompany major illness (eg, ARDS), the successful treatment of DIC depends on treating the underlying condition. Diagnosis: The diagnosis of DIC is usually contemplated in the critically ill patient who develops thrombocytopenia, and occasionally an elevated PT. The following list details other laboratory findings that are caused by the effect of plasmin on fibrinogen. They result in increased levels of fibrin monomers and feedback stimulation of the fibrinolytic system, yielding fibrin degradation products and increased plasmin formation. The most important element of therapy is to identify and treat the underlying cause. If there is evidence of thrombosis (eg, PE), begin heparin therapy with a loading dose of 100 U/kg followed by a drip at 10–15 U/kg/h (see Chapter 22). If the patient is bleeding severely, despite replacement therapy with FFP and platelets, begin antifibrinolytic therapy with epsilon–aminocaproic acid (Amicar). Line Sepsis Indwelling catheters not only provide a convenient means of infusing fluids and medica- tions, but also act as a portal of entry for bacteria. With the widespread use of indwelling intravenous catheters (eg, central venous lines), the diagnosis of infection from the cath- eter itself must be considered when evaluating a febrile patient in the ICU.
The mushroom stimulates the immune system generic mircette 15mcg online, and their im- Preparations mune systems are already in overdrive buy 15mcg mircette fast delivery. Maitake mushroom may be eaten fresh order 15 mcg mircette fast delivery, made into a tea order 15mcg mircette, taken as capsules, or taken as an alcohol extract. Side effects When maitake mushroom is cooked, the taste is Side effects are rare and the only known one is pos- woodsy. The mushroom must be washed and soaked in sible loose bowels and stomach upset if the whole mush- water until it turns soft. Maitake mush- rooms will keep from five to 10 days if properly stored Interactions in a paper bag in the refrigerator. As of 2002, no interactions between maitake and Dried maitake pieces may be made into a tea by using prescription medications have been reported. To make the tea, it is first required to grind the BOOKS dried maitake in a coffee grinder, then it is added to water, American Cancer Society (ACS). Capsules are available in 150-500 mg with a stan- dardized D-fraction powder extract of 10 mg. They may PERIODICALS be taken twice a day between meals or first thing in the Haugen, Jerry and George B. Cap- fola frondosa) D-Fraction on the Control of the T Lymph sules should be stored in a cool dry place. A recent gov- ORGANIZATIONS ernment panel warned that disaster looms over Africa Mushroom Council. It is predicted that OTHER within five years, malaria will kill about as many people “Maitake (Grifola frondosa). The spread of malaria is becoming even more serious as the Sharon Crawford parasites that cause malaria develop resistance to the Rebecca J. In late 2002, a group of public health researchers in Thailand reported that a combination treatment regimen involving two drugs known as dihydroartemisinin and azithromycin shows promises in treating multidrug-resistant malaria in south- east Asia. Malaria Definition Causes & symptoms Malaria is a serious infectious disease spread by cer- Human malaria is caused by four different species tain mosquitoes. Many animals can get malar- (occurs frequently in a particular locality) in many third ia, but human malaria does not spread to animals. Isolated, small outbreaks sometimes turn, animal malaria does not spread to humans. The parasites enter the blood stream and travel to the liver, where they multiply. By the time a patient shows symptoms, the parasites have reproduced very rapidly, Malaria is a growing problem in the United States. Although only about 1400 new cases were reported in Malaria cannot be casually transmitted directly from the United States and its territories in 2000, many in- one person to another. In addition, locally transmit- fected person and then passes the infection on to the next ted malaria has occurred in California, Florida, Texas, human it bites. It is also possible to spread malaria via Michigan, New Jersey, and New York City. This is ia can be transmitted in blood, the American blood sup- why all blood donors are carefully screened with ques- ply is not screened for malaria. Nevertheless, at least being advised to screen returning travelers with fever for 89 cases of so-called airport malaria, in which travelers malaria, and a team of public health doctors in Minneso- contract malaria while passing through crowded airport ta is recommending screening immigrants, refugees, and terminals, have been identified since 1969. The incubation period is not appear until eight to 10 months after the mosquito usually between eight and 12 days for falciparum bite occurred. GALE ENCYCLOPEDIA OF ALTERNATIVE MEDICINE 2 1279 The primary symptom of all types of malaria is the (45–60 min) in making the malaria parasites visible “malaria ague” (chills and fever), which corresponds to under a microscope. The second is a bioassay technique the “birth” of the new generation of the parasite. It al- trollable shivering for an hour or two, followed by a lows for a very accurate estimation of parasite develop- rapid spike in temperature (as high as 106°F [41.