By M. Achmed. Miami Christian University.
This route may also be attractive in 306 potentially facilitating the transport of peptides and proteins digoxin 0.25 mg mastercard, either as drugs or drug carriers buy digoxin 0.25 mg amex, to their target sites within the eye purchase digoxin 0.25 mg overnight delivery. A drop is placed in the inferior cul-de-sac by gently pulling the lower lid away from the globe and creating a pouch to receive the drop. After gently lifting the lid to touch the globe, a small amount of liquid is entrapped in the inferior conjunctival sac, where it may be retained up to twice as long as when it is simply dropped over the superior sclera. Drainage from the cul-de-sac may further be reduced by punctual occlusion or simple eyelid closure, which not only maximizes the contact of drug with the periocular tissues but also slows the rate of the systemic absorption. Following dosing, the normal manoeuvre results in a gradient across he eye as illustrated in Figure 12. This suggests that dosing under the upper lid would improve delivery: however, this method of dosing would be difficult for the patient. The local/systemic effect balance can be improved by reducing the size of the eyedrop and tips capable of delivering a drop of 8–10 μl have been designed by varying the relationship between the inner and outer diameters of the end of the tip. The use of smaller eye droppers results in a reduced systemic drug absorption, but their use in commercial containers has not been popular. Although a smaller drop may be retained longer in the conjunctival sac, the instilled volume less than 8 μl is not recommended due to the difficulty in making up a suitable concentration for the eyedrop. The process of passive diffusion initially involves partition of a drug between the aqueous fluid at the site of the application and the lipoidal cell membrane. The drug in solution in the membrane then diffuses across the membrane followed by a second partition of drug between the membrane and the aqueous fluids within the site of absorption. Two approaches can be used to enhance corneal drug permeability: • modify integrity of the corneal epithelium transiently; • modify the chemical structure of the drug. Flow from the lacrimal gland dilutes the concentration of drug in the tear film pulled up from the lower marginal strip The first approach can be accomplished by exposing the eye to compounds such as chelating agents and surfactants, but it has hardly been explored due to the sensitivity of this particular tissue. The second approach commonly focuses on changing the physicochemical properties of the drug, such as lipophilicity, solubility and pKa. Physicochemical factors associated with the drug moiety The physicochemical properties of a molecule which affect its absorption across the cornea are broadly the same as those affecting transepithelial absorption at any site and have been discussed extensively in Chapter 1 (Section 1. These factors influence the mechanism and rate of drug absorption through the cornea. This is well illustrated by efforts in developing topically effective carbonic anhydrase inhibitors such as dorzolamide through significant alternations in chemical structure. Prodrug approach In ophthalmic research, a prodrug is designed to be inactive with some degree of biphasic solubility as the cornea is a biphasic tissue in structure. It will be transformed into the active drug by either an enzymatic or a chemical processes in the eye. Due to its increased lipophilicity, 308 dipivefrin penetrates the corneal epithelium 10 times more readily than epinephrine. The higher penetration of the drug results in a smaller dose being required, thus reducing systemic side-effects. For potent drugs such as timolol, which has the potential to cause serious systemic side-effects, such a corresponding reduction would be clinically valuable. By other routes, this can be achieved by adhering a reservoir of drug as a membrane-controlled patch or osmotic pump on the epithelium (see Chapters 4 and 8). However, the function of the eye as a visual apparatus limits the possibility of such an attachment of these dosage forms to the cornea. To optimize ocular drug bioavailability by increasing concentration gradient of the drug, considerable efforts have been devoted to minimize solution drainage. This would improve drug residence time on the sclera and cornea, thereby modifying the drug pulse entry characteristics. Other techniques include the use of novel formulations allowing drugs to be delivered in a controlled manner over a long period. A suitable placement of an eyedrop and a reduced instilled volume also contribute to the improved ocular bioavailability. Viscous systems A popular approach to improve ocular drug bioavailability is to incorporate soluble polymers into an aqueous solution to extend the drug residence time in the cul-de-sac. It is reasoned that the solution viscosity would be increased and hence solution drainage would be reduced. They have common properties: • a wide range of viscosity (400 to 15,000 cps); • compatibility with many topically applied drugs; • increased stability of the lacrimal film. Bioadhesives Bioadhesion is an interfacial phenomenon in which a synthetic or natural polymer becomes attached to a biological substrate by means of interfacial forces.
Woller buy digoxin 0.25 mg with visa, Buboltz generic digoxin 0.25 mg fast delivery, and Lovelace (2007) further stated that differences in reactance levels for minority groups may result from disparate environmental opportunities related to discrimination that restricts free behavior generic 0.25 mg digoxin with amex, especially for Blacks and Hispanic/Latinos. Thus, reactance behaviors experienced in society may be generalized to relationships with health care providers implementing the treatment regimen. The vast amount of literature on lack of compliance and adherence attest to the continual resistance of individuals to taking medications, even though they may receive pertinent information, interventional strategies, and admonishments (Fogarty, 1997; Pound et al. Several authors contend that because varying degrees of resistance exist and are usually hidden from health care providers, it is highly unlikely that individuals will stop resisting prescribed medications (Fogarty, 1997; Pound et al. Intrinsic motivation as described by Cox and Brehm‘s reactance theory may provide insight into factors that promote adherence behaviors. The rationale for reactant behaviors and resulting resistance to the treatment regimen, particularly medication- taking, warrants further exploration. Cognitive appraisal provides insight into the client‘s perceptions and interpretation of his or her health status, behavioral choices, and interaction with the health care provider (Cox, 1982). Importantly, the client‘s perceptions and interpretations are representative of his or her reality and may or may not reflect that of the health care professional (Carter & Kulbok, 1995; Cox, 1982). While educational information is usually beneficial for individuals who are motivated to adhere to the treatment regimen but unlearned in regimen process, individuals unmotivated in adherence and already knowledgeable are unlikely to improve with additional educational information (Becker, 1985). Thus, client education is essential, although its effectiveness may be questioned, especially when intrinsic motivation is lacking. Becker (1985) asserts that providing information to clients about diagnosed illnesses and prescribed treatments have not increased adherence. However, literacy was not reported as an issue in this study even though over 45% of the sample had less than a high school education. Literacy issues may be one of the primary reasons for uncertainty of educational effectiveness. Low literacy levels can result in difficulty understanding health information, accessing health care, following instructions from a health care provider, and taking medications correctly; all of which 62 contribute to poor adherence to the treatment regimen, uncontrolled chronic disease, and increased health care costs (Safeer & Keenan, 2005). Milio (1976) exerts is that it is not enough to make clients knowledgeable about healthy lifestyle choices without assuring that clients have ready access to the treatment options promoted. If health care providers adequately assess clients prior to implementing treatment and allow clients an opportunity to exert control over determining optimal health for themselves, then the actions necessary to attain their health status could be implemented according to the client‘s environmental limitations (Carter & Kulbok, 1995; Cox, 1982). Adequate assessment of the client‘s ability to practice positive health behaviors within the environmental resources available may provide a realistic expectation for the client to succeed in adhering to the health care regimen and allow the health care provider an opportunity to individualize the health care regimen, thus making adherence a viable possibility. As defined by Riegel, Lee, Dickson, and Carlson (2009), self- care is a decision-making process that clients naturally use to choose behaviors to maintain their physiological status and manage any symptoms that may occur. Maintenance refers to living a healthy lifestyle, adhering to the treatment regimen, and monitoring symptoms that may require decision making if a response is needed. Conversely, management is the deliberate process of action to recognize symptoms, evaluate the need to act, implement a treatment strategy, and evaluate treatment effectiveness (Riegel et al. Thus, clients are left to self-manage symptoms that arise and engage in decision-making and problem-solving to maintain their physiological status (Pascucci et al. Therefore, clients who are expertly engaged in self-care should possess qualities such as knowledge, experience, and skill relevant to their disease process (Riegel et al. Evidence has shown that education alone is not effective in improving client adherence to antihypertensive medications. However, dietary advice has shown modest short-term improvements in fat intake and fruit and vegetable consumption. Conversely, advice to increase physical activity has not shown effectiveness (Viera & Jamieson, 2007). The system was designed to initiate alerts if the client does not complete scheduled self-testing, did not take medications as prescribed, or exceeded specified clinical parameter thresholds. A nurse monitored the system, contacted clients to counsel and educate and notified the physician of client events monthly and problem areas as needed. Client trust is an essential element of the client and health care provider relationship that directly impacts adherence to the treatment regimen (P. According to Cox (2003), the content of the health care provider‘s interaction and sensitivity to the client‘s elements of singularity are evidenced by the client‘s satisfaction with care, which is strongly predictive of subsequent adherent behavior. However, trust with 65 Black clients differs from White clients because Blacks generally consider health care providers as untrustworthy. Therefore, signals of distrust by Blacks may include behaviors such as anger (Watkins & Terrell, 1988), assertive behaviors that are oftentimes misinterpreted as attitudinal or militant (Fongwa, 2002), and request for the services of a Black health care provider (Flack et al. Lack of trust in health care providers hinders the establishment of a trusting client-health care provider relationship. Factors that may impede relationship development include health care disparities (Greer, 2010; L.
Evidence of arthropathy was characterized as either physical or historical evidence digoxin 0.25mg line. Physical evidence of arthropathy may have included but was not necessarily limited to: warmth purchase digoxin 0.25 mg, redness buy digoxin 0.25mg line, joint effusion, tenderness, synovial thickness, abnormal gait or limp, weakness, and/or limited joint mobility/motion. Historical evidence included joint and/or periarticular tissue pain and/or stiffness. Diagnostic imaging demonstrating structural damage or change was also accepted as evidence of arthropathy. Evidence of arthropathy may have been further categorized as weak or strong evidence. Historical data was considered weak evidence; joint effusion, synovial thickness, limited motion and diagnostic imaging findings were examples of strong evidence. Relevant modifiers of evidence included severity, duration, and the presence of concurrent factors such as trauma, infection, and other confounding diseases (e. In addition, concurrence of parameters or change in parameters over time was given greater weight (e. In making the determination of relationship to study drug, multiple factors were considered. The 3 major considerations were any pre-existing conditions, conditions with clear alternative etiology (i. Generally, conditions that began more than 1 year after the administration of study drug were not considered related to study drug. For this analysis, all classification categories of drug relatedness were combined. It should be noted that arthritis was summarized in a descriptive fashion with other adverse events. The patient had arthralgia as an initial event, which was later clarified as an event of neck pain. Of the 1,029 patients, 510 were in the ciprofloxacin group, and 519 were in the control group. Since the control group was added 2 years after the study started, and since the enrollment process was not randomized, the patient distribution within centers was highly variable. Most of the centers enrolled all or nearly all of their patients into the same treatment group, and very few centers had similar numbers of patients in the two groups. Of the 68 centers, 35 enrolled only ciprofloxacin patients, 30 enrolled patients into both groups, and 3 enrolled only control patients. Most centers enrolled between 1 and 40 patients (only 4 centers enrolled more than 40). Center 7 enrolled 223 control patients, accounting for 43% of the control group population, while only enrolling 14 (3%) ciprofloxacin patients. As shown in Table 3, 63 ciprofloxacin and 26 control patients did not complete the study drug as planned. The ciprofloxacin patients prematurely discontinued treatment more often than the control patients did (12% versus 5%). The reason for discontinuation with the largest difference between groups was adverse event (3% for ciprofloxacin patients, <1% for control patients), but in all categories there were more ciprofloxacin patients than control patients. Of those 54, information obtained by the applicant for 19 patients suggested they indeed had received study drug. However, for these 19 patients, information regarding treatment duration, formulation, and dosage was not available. These patients were excluded from the safety analysis, leaving 487/510 (95%) in the ciprofloxacin group and 507/519 (98%) valid for safety. Known underlying rheumatological disease, joint problems secondary to trauma or pre-existing conditions known to be associated with arthropathy were to be excluded from the study. However, 7% (32/487) of ciprofloxacin patients and 5% (24/507) control patients were enrolled with a medical history of any abnormal musculoskeletal or connective tissue finding. Clinical Reviewer’s Comment: The differences in baseline abnormalities and medical histories may make it difficult to assess any potential drug effect on gait or joint appearance and will be taken into consideration when reviewing musculoskeletal adverse event rates and arthropathy rates for the two treatment groups.
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