Pharmacology of Neural Blockade

Author(s):  
Christopher M. Duncan ◽  
Paula A. Craigo

Chapter 2 reviews the mechanism of action for local anesthetics. Clinical features such as potency, onset of action, duration, and dose are discussed. Drug metabolism, toxicity (local and systemic), and its treatment are included. The chapter concludes with additional information on adjuvant medications (eg, epinephrine, clonidine) used to extend or enhance the clinical effects of local anesthetics.

1997 ◽  
Vol 14 (4) ◽  
pp. 453-456 ◽  
Author(s):  
Thomas G. Bruno ◽  
Joseph F. Greco

The tendency toward the use of local anesthetics for longer outpatient procedures such as hair transplantation micrograft megasessions and cosmetic facial plastic surgery calls for special consideration of potential toxicity and adverse reactions. As longer procedures on larger, highly vascular surface areas are attempted, the potential for adverse reactions becomes more likely. Understanding the pharmacological properties that govern the clinical effects of local anesthetics, such as onset of action, duration of action, and adverse effects, will prompt the clinician to carefully consider the technique of administration and the dosing limits of these potentially toxic anesthetic drugs.


Author(s):  
D Vermeulen ◽  
M Wooding ◽  
K Outhoff ◽  
T Dippenaar

Introduction: This study aimed to examine the effect of breakages and re-introduction into cold chain on the rocuronium bromide compound. Rocuronium bromide is frequently used in routine theatre lists and plays a vital role in modified rapid sequence induction and intubation for emergency patients who have contraindications to the primarily used muscle relaxant, succinylcholine. With the current practice of removing the drug from, and then reintroducing it into the cold chain, unpredictable clinical effects, including delayed onset of action and shortened duration of action have been observed. This may pose significant risks to the patient. Methods: Rocuronium bromide was subjected to different clinically applicable storage and temperature scenarios, after which the compound was analysed for integrity and quantities of the active compound, including detection of possible degradation products, by mass spectrometry, and compared to cold chain control samples. Results: There were no significant differences between any of the temperature exposure groups (18 °C or 24 °C) or between single or double exposures at these temperatures. No statistically significant difference could be demonstrated between the two control groups (cold chain preserved and room temperature controlled) with testing done at weeks one and six. However, week twelve analysis revealed a statistically significant result which translates to a 26 μg/ml difference, which clinically would have no effect. Substantial results were obtained with a secondary exposure to air; which lead to a 20% decrease in rocuronium concentration (p = 0.02). Conclusion: Practice should be adapted by keeping careful documentation as to when cold-chain was broken, and when the recommended 12 week period will lapse. Vial sharing as a standard is not recommended. If small quantities are repeatedly withdrawn from the vial during a prolonged case, the unused contents should be discarded after eight hours.


Author(s):  
L.Ya. Fedorich

Objective — to study the modern classification, mechanisms of action and clinical effects of vitamin A derivatives, to analyze retinoid for local treatment of various dermatoses with a universal mechanism of action at the epidermis and dermis levels. Materials and methods. A review of the literature and an analysis of the results of international clinical trials of drugs based on the natural retinoid of the first generation — tretinoin (retinoic acid) is presented. The works of dozens of authors since 1980s to the present day are analyzed. Most sources provide detailed information on the results of topical retinoids in acne therapy, which are the base of clinical guidelines. Long-term (6 months or more) studies of retinoic acid-based preparations carried out in recent decades have discovered the unique clinical effects of tretinoin in the treatment of skin photoaging, actinic keratosis, etc. They are achieved due to the effect of tretinoid on the nuclear receptors of keratinocytes and fibroblasts. Results and discussion. The molecular mechanisms of action of retinoic acid, realizing the cellular and tissue effects of the most studied retinoid, are systematized and grouped in a single review. It has been proven that a unique feature of tretinin is its ability to activate directly all subtypes of RARs- and, indirectly, RARs-nuclear receptors of skin cells. A new modern drug for external use is presented — AltrenoТМ lotion containing micronized 0.05 % tretinoin in combination with sodium hyaluronate, soluble collagen and glycerin. This combination exhibits the expected clinical efficacy in acne therapy and prevents side effects such as dryness, redness and exfoliation. AltrenoТМ is approved for use in children of 9 years of age and older. Conclusions. Tretinoin (retinoic acid) is a modern powerful retinoid with a universal mechanism of action, recommended for the treatment of acne.


2019 ◽  
Vol 35 (3) ◽  
pp. 119-125 ◽  
Author(s):  
Irene Abuan ◽  
Kristine H. Wong ◽  
Benjamin Bolinske ◽  
Katherine S. Hale

Objective: To review the pharmacology, safety, and efficacy of andexanet alfa (andexanet), a recombinant modified human factor Xa protein for reversal of factor Xa inhibitors. Data Sources: English-language articles were obtained from MEDLINE (1966 to February 2019) using the following key words: andexanet, andexanet alfa, AndexXa, factor Xa, antidote, and reversal. Citations from selected articles were used to identify additional sources. Study Selection and Data Extraction: Available published articles reporting results of human studies of andexanet alfa were reviewed for inclusion. Prescribing information was used to obtain additional information regarding pharmacology, adverse events, contraindications, and precautions. Data Synthesis: Andexanet is a recombinant modified human factor Xa protein indicated for reversal of rivaroxaban and apixaban in patients with life-threatening or uncontrolled bleeding. Onset of action is rapid and sustained throughout bolus and infusion administration. Medication effects subside 1 to 3 hours postadministration. Andexanet is administered as a bolus followed by a 120-minute continuous infusion. Anti-factor Xa activity was reduced by 95% and 92% in apixaban and rivaroxaban groups, respectively, on infusion completion. Thrombin regeneration occurred within 2 to 5 minutes in up to 96% of patients. Minor infusion reactions and gastrointestinal upset were reported most. A black box warning for thrombotic events, cardiac arrest, ischemia, and sudden death should be noted. Conclusions: Andexanet is effective in reversing rivaroxaban and apixaban anticoagulation due to reduction of anti-factor Xa activity in healthy patients and those with acute major bleeds. Safety concerns, including thrombotic risks, exist and should be assessed against individual patient factors.


JAMA ◽  
1977 ◽  
Vol 238 (13) ◽  
pp. 1383-1385 ◽  
Author(s):  
R. H. de Jong

2020 ◽  
Vol 13 ◽  
pp. 175628481989753 ◽  
Author(s):  
William D. Chey ◽  
Eric D. Shah ◽  
Herbert L. DuPont

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder with a multifactorial pathophysiology. The gut microbiota differs between patients with IBS and healthy individuals. After a bout of acute gastroenteritis, postinfection IBS may result in up to approximately 10% of those affected. Small intestinal bacterial overgrowth (SIBO) is more common in patients with IBS than in healthy individuals, and eradication of SIBO with systemic antibiotics has decreased symptoms of IBS in some patients with IBS and SIBO. The nonsystemic (i.e. low oral bioavailability) antibiotic rifaximin is indicated in the United States and Canada for the treatment of adults with IBS with diarrhea (IBS-D). The efficacy and safety of 2-week single and repeat courses of rifaximin have been demonstrated in randomized, placebo-controlled studies of adults with IBS. Rifaximin is widely thought to exert its beneficial clinical effects in IBS-D through manipulation of the gut microbiota. However, current studies indicate that rifaximin induces only modest effects on the gut microbiota of patients with IBS-D, suggesting that the efficacy of rifaximin may involve other mechanisms. Indeed, preclinical data reveal a potential role for rifaximin in the modulation of inflammatory cytokines and intestinal permeability, but these two findings have not yet been examined in the context of clinical studies. The mechanism of action of rifaximin in IBS is likely multifactorial, and further study is needed.


2020 ◽  
Vol 7 ◽  
pp. 237428952092153
Author(s):  
Maria Kamal ◽  
Mariam Ghafoor ◽  
Urooba Nadeem ◽  
Aliya N. Husain

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040 .1


2002 ◽  
Vol 2 (6) ◽  
pp. 849-858 ◽  
Author(s):  
Olivier Lambert ◽  
Michel Bourin

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