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Blocking Drugs (blocking + drug)

Distribution by Scientific Domains

Medical Sciences	96%

Distribution within Medical Sciences

Anesthesia & Pain Management	83%
Pharmacology & Pharmaceutical Medicine	12%

Kinds of Blocking Drugs

neuromuscular blocking drug

Selected Abstracts

Effects of SZ1677, a new non-depolarizing steroidal neuromuscular blocking drug, and rocuronium on two laryngeal muscles and the anterior tibial muscle in guinea pigs

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2006
A. Michalek-Sauberer
Background:, SZ1677 is a new neuromuscular blocking drug structurally related to rocuronium. We compared the effect of an ED90 of SZ1677 (25 ,g/kg) with that of rocuronium (100 ,g/kg) in guinea pig laryngeal and peripheral muscles. Methods:, Electromyography was used to quantify neuromusc-ular blockade at the posterior cricoarytenoid muscle, the thyroarytenoid muscle and the anterior tibial muscle after SZ1677 (n = 10) and rocuronium (n = 9). Results:, Maximum neuromuscular blockade was similar after SZ1677 and rocuronium (83 ± 11% vs. 89 ± 11%; thyroarytenoid muscle: 91 ± 8% vs. 97 ± 3%; anterior tibial muscle: 91 ± 15% vs. 96 ± 3%, respectively). Onset time of neuromuscular blockade at the laryngeal muscles was similar for the two neuromuscular blocking drugs; it was shorter at the thyroarytenoid muscle (67 ± 32 s vs. 42 ± 40 s) than at the posterior cricoarytenoid muscle (101 ± 26 s vs. 102 ± 108 s). Onset time at the anterior tibial muscle was longer after SZ1677 (114 ± 34 s) than after rocuronium (68 ± 46 s); P < 0.05. Neuromuscular recovery was faster after SZ1677 (interval 25%,75%: posterior cricoarytenoid muscle: 222 ± 66 s; thyroarytenoid muscle: 192 ± 92 s; tibial muscle 149 ± 55 s) than after rocuronium (450 ± 148 and 464 ± 183 s, 292 ± 86 s, respectively); P < 0.05. Conclusions:, In guinea pigs, SZ1677 offers a rapid onset of neuromuscular blockade at a laryngeal adductor muscle with a shorter duration than rocuronium. Regardless of the drug used, the course of neuromuscular blockade differs not only between peripheral muscles and the larynx but also between antagonistic laryngeal muscles. The differences seem to be species specific. [source]

The place of suxamethonium in pediatric anesthesia

PEDIATRIC ANESTHESIA, Issue 6 2009
MARCIN RAWICZ MD
Summary Suxamethonium is a drug that promotes very strong views both for and against its use in the context of pediatric anesthesia. As such, the continuing debate is an excellent topic for a ,Pro,Con' debate. Despite ongoing efforts by drug companies, the popular view still remains that there is no single neuromuscular blocking drug that can match suxamethonium in terms of speed of onset of neuromuscular block and return of neuromuscular control. However, with this drug the balance of benefit vs risk and side effects are pivotal. Suxamethonium has significant adverse effects, some of which can be life threatening. This is particularly relevant for pediatric anesthesia because the spectrum of childhood diseases may expose susceptible individuals to an increased likelihood of adverse events compared with adults. Additionally, the concerns related to airway control in the infant may encourage the occasional pediatric anesthetist to use the drug in preference to slower onset/offset drugs. In the current environment of drug research, surveillance and licensing, it is debatable whether this drug would achieve the central place it still has in pediatric anesthesia. The arguments for and against its use are set out below by our two international experts, Marcin Rawicz from Poland and Barbara Brandom from USA. This will allow the reader an objective evaluation with which to make an informed choice about the use of suxamethonium in their practice. [source]

The undesirable effects of neuromuscular blocking drugs

ANAESTHESIA, Issue 2009
C. Claudius
Summary Neuromuscular blocking drugs are designed to bind to the nicotinic receptor at the neuromuscular junction. However, they also interact with other acetylcholine receptors in the body. Binding to these receptors causes adverse effects that vary with the specificity for the cholinergic receptor in question. Moreover, all neuromuscular blocking drugs may cause hypersensitivity reactions. Often the symptoms are mild and self-limiting but massive histamine release can cause systematic reactions with circulatory and respiratory symptoms and signs. At the end of anaesthesia, no residual effect of a neuromuscular blocking drug should be present. However, the huge variability in response to neuromuscular blocking drugs makes it impossible to predict which patient will suffer postoperative residual curarization. This article discusses the undesirable effects of the currently available neuromuscular blocking drugs including the definitions, diagnosis and causes of hypersensitivity reactions and postoperative residual curarisation. [source]

Sugammadex in clinical practice

ANAESTHESIA, Issue 2009
R. K. Mirakhur
Summary The availability of sugammadex allows greater flexibility in the use of rocuronium and vecuronium during anaesthesia and surgery. The neuromuscular block induced by both drugs can be reversed from both superficial and deep levels of block by adjusting the dose of sugammadex. The dose of sugammadex for reversal of shallow block produced by these neuromuscular blocking drugs is approximately 2 mg.kg,1 and for deep block the dose is 4 mg.kg,1. A larger dose of sugammadex (16 mg.kg,1) administered 3 min after the neuromuscular blocking drug allows rapid reversal of a neuromuscular block induced by 1,1.2 mg.kg,1 of rocuronium, thereby raising the possibility of using rocuronium as a replacement for suxamethonium. The use of sugammadex has not been reported to be associated with recurrence of block provided a dose that is adequate for reversal has been used. Sugammadex appears to have an acceptable safety profile. There are no requirements for dose adjustment for age or the use of potent volatile anaesthetic agents. [source]

Proarrhythmic potential of halofantrine, terfenadine and clofilium in a modified in vivo model of torsade de pointes

BRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2002
Andrew J Batey
This study was designed to compare the proarrhythmic activity of the antimalarial drug, halofantrine and the antihistamine, terfenadine, with that of clofilium a K+ channel blocking drug that can induce torsade de pointes. Experiments were performed in pentobarbitone-anaesthetized, open-chest rabbits. Each rabbit received intermittent, rising dose i.v. infusions of the ,-adrenoceptor agonist phenylephrine. During these infusions rabbits also received increasing i.v. doses of clofilium (20, 60 and 200 nmol kg,1 min,1), terfenadine (75, 250 and 750 nmol kg,1 min,1), halofantrine (6, 20 and 60 ,mol kg,1) or vehicle. Clofilium and halofantrine caused dose-dependent increases in the rate-corrected QT interval (QTc), whereas terfenadine prolonged PR and QRS intervals rather than prolonging cardiac repolarization. Progressive bradycardia occurred in all groups. After administration of the highest dose of each drug halofantrine caused a modest decrease in blood pressure, but terfenadine had profound hypotensive effects resulting in death of most rabbits. The total number of ventricular premature beats was highest in the clofilium group. Torsade de pointes occurred in 6 out of 8 clofilium-treated rabbits and 4 out of 6 of those which received halofantrine, but was not seen in any of the seven terfenadine-treated rabbits. These results show that, like clofilium, halofantrine can cause torsade de pointes in a modified anaesthetized rabbit model whereas the primary adverse effect of terfenadine was cardiac contractile failure. British Journal of Pharmacology (2002) 135, 1003,1012; doi:10.1038/sj.bjp.0704550 [source]

Serum angiotensin-converting enzyme and frequency of severe hypoglycaemia in Type 1 diabetes: does a relationship exist?

DIABETIC MEDICINE, Issue 12 2007
N. N. Zammitt
Abstract Aims An association has been described between elevated serum angiotensin-converting enzyme (ACE) and an increased risk of severe hypoglycaemia (SH). To ascertain whether this reported association could be replicated in a different country, it was re-examined in 300 individuals with Type 1 diabetes. Methods People with Type 1 diabetes, none of whom was taking renin,angiotensin system blocking drugs, were recruited. Participants recorded the frequency with which they had experienced SH. Glycated haemoglobin (HbA1c) and serum ACE were measured. The difference in the incidence of SH between different quartiles of ACE activity and the relationship between serum ACE and SH were examined using non-parametric statistical tests and a negative binomial model. Results Data were obtained from 300 patients [158 male; HbA1c median (range) 8.2% (5.2,12.8%), median age 36 years (16,88); duration of diabetes 14.5 years (2,49)]. The incidence of SH was 0.93 episodes per patient year. The mean incidence of SH in the top and bottom quartiles of ACE activity was 0.5 and 1.7 episodes per patient year, respectively, but this difference was not statistically significant (P = 0.075). Spearman's test showed a very weak, although statistically significant, association between serum ACE level and SH incidence (r = 0.115, P = 0.047). The binomial model also showed a statistically significant (P = 0.002), but clinically weak, relationship between serum ACE and SH. Conclusions The present survey showed a weak relationship between serum ACE and the frequency of SH, the clinical relevance of which is unclear. This limits the proposed role for serum ACE as an index of risk for SH. [source]

Effects of SZ1677, a new non-depolarizing steroidal neuromuscular blocking drug, and rocuronium on two laryngeal muscles and the anterior tibial muscle in guinea pigs

Tracheal intubation without neuromuscular blocking drugs

PEDIATRIC ANESTHESIA, Issue 6 2009
James F. Mayhew
No abstract is available for this article. [source]

Tracheal intubation without neuromuscular blocking drugs in children

PEDIATRIC ANESTHESIA, Issue 3 2009
FFPMRCA, FRCPCH, NEIL S. MORTON MBCHB
No abstract is available for this article. [source]

A combination of total intravenous anesthesia and thoracic epidural for thymectomy in juvenile myasthenia gravis

PEDIATRIC ANESTHESIA, Issue 4 2007
OLIVER BAGSHAW MBChB FRCAArticle first published online: 12 DEC 200
Summary Juvenile myasthenia gravis is the acquired form of the disease in children and presents with ocular signs, fatigability, weakness and bulbar problems. The majority of patients demonstrate thymic hyperplasia and have been shown to benefit from thymectomy. The main considerations for the anesthesiologist are the degree of muscle weakness, the muscle groups involved and sensitivity to neuromuscular blocking drugs and volatile agents. Total intravenous anesthesia (TIVA) with epidural analgesia is probably the anesthetic technique of choice, although the latter is often avoided, because of the risk of a very high block. Two cases of thymectomy are presented where anesthesia was provided using a combination of TIVA and thoracic epidural analgesia. Both patients tolerated the technique well and had an uncomplicated perioperative course. [source]

Adverse effects of neuromuscular blocking agents based on yellow card reporting in the U.K.: are there differences between males and females?,

PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 3 2006
FRCA, Karen Patricia Light MBBS
Abstract Background Adverse drug reactions (ADRs) are known to occur during anaesthesia; in the U.K. such ADRs may be reported through the Yellow Card Scheme (YCS). Our aim was to determine the demographics of ADRs to neuromuscular blocking drugs without formal causality assessment. Methods A retrospective analysis of ADRs to seven neuromuscular blocking drugs reported via the YCS during a greater than 30-year period was performed. Sex and age were analysed in order to identify at risk groups. Results Of 998 reports, 969 included gender. Non-allergic suspected reactions occurred with almost the same frequency as those with an allergic component. The majority occurred in females 676 (70%), and significant sex differences were measured between drugs. Males were more likely to have suffered an ADR to atracurium (p,=,0.01) whilst females experienced more ADRs to suxamethonium (p,=,0.01). ADRs proved fatal in 81 (9%) of the 950 reports for single drugs. Mortality following suxamethonium was significantly higher in males at 22% compared with 9% females (p,<,0.001). More women than men were reported to have allergic reactions, 73% (362/499) compared with 27% (137/499) respectively. The female:male ratio for ADRs was reversed for subjects <,10 years compared with peak ADR reports during the decade from 31,40 years. Conclusions Sex differences in mortality exist in this analysis. The unexpected high frequency of non-allergic ADRs suggests that morbidity and mortality from reactions to established drugs is twice that expected from allergic reactions alone. Standards and guidance for the reporting of ADRs warrant urgent development. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Conformational changes induced by a single amino acid substitution in the trans -membrane domain of Vpu: Implications for HIV-1 susceptibility to channel blocking drugs

PROTEIN SCIENCE, Issue 10 2007
Sang Ho Park
Abstract The channel-forming trans -membrane domain of Vpu (Vpu TM) from HIV-1 is known to enhance virion release from the infected cells and is a potential target for ion-channel blockers. The substitution of alanine at position 18 by a histidine (A18H) has been shown to render HIV-1 infections susceptible to rimantadine, a channel blocker of M2 protein from the influenza virus. In order to describe the influence of the mutation on the structure and rimantadine susceptibility of Vpu, we determined the structure of A18H Vpu TM, and compared it to those of wild-type Vpu TM and M2 TM. Both isotropic and orientationally dependent NMR frequencies of the backbone amide resonance of His18 were perturbed by rimantadine, and those of Ile15 and Trp22 were also affected, suggesting that His18 is the key residue for rimantadine binding and that residues located on the same face of the TM helix are also involved. A18H Vpu TM has an ideal, straight ,-helix spanning residues 6,27 with an average tilt angle of 41° in C14 phospholipid bicelles, indicating that the tilt angle is increased by 11° compared to that of wild-type Vpu TM. The longer helix formed by the A18H mutation has a larger tilt angle to compensate for the hydrophobic mismatch with the length of the phospholipids in the bilayer. These results demonstrate that the local change of the primary structure plays an important role in secondary and tertiary structures of Vpu TM in lipid bilayers and affects its ability to interact with channel blockers. [source]

Monitoring sedation in the critically ill child

ANAESTHESIA, Issue 5 2010
A. Lamas
Summary Sedation is an essential part of the management of the critically ill child, and its monitoring must be individualised and continuous in order to adjust drug doses according to the clinical state. There is no ideal method for evaluating sedation in the critically ill child. Haemodynamic variables have not been found to be useful. Clinical scales are useful when sedation is moderate, but are limited by their subjective nature, the use of stimuli, and the impossibility of evaluating profoundly sedated patients or those receiving neuromuscular blocking drugs; in addition, many of these scales have not been evaluated in children. The COMFORT scale is the most appropriate, as it was designed and validated for critically ill children requiring mechanical ventilation. Electroencephalography-derived methods permit continuous monitoring, provide an early indication of changes in the level of sedation, and facilitate a rapid adjustment of medication. However, these methods were designed and validated for patients under anaesthesia and their results cannot be fully extrapolated to the critically ill patient; in addition, some of them have not been validated in small children and there is still little experience in critically ill children. The main indications for the use of these methods are in patients with deep sedation and/or neuromuscular blockade. The bispectral index is the most widely used method at the present time. Analysis and comparison of the efficacy of the different methods for evaluating sedation in the critically ill child is required. [source]

The use of sugammadex in a patient with myasthenia gravis

ANAESTHESIA, Issue 3 2010
C. Unterbuchner
Summary Myasthenia gravis, affecting neuromuscular transmission, leads to a large variability in sensitivity to depolarising and non-depolarising neuromuscular blocking drugs. We report the successful use of the modified ,-cyclodextrin sugammadex in a myasthenic patient to reverse a rocuronium-induced deep level of neuromuscular block. After spontaneous neuromuscular recovery of T2 (second twitch of the train-of-four series), we administered 2 mg.kg,1 of sugammadex intravenously, reversing neuromuscular blockade to a train-of-four ratio (T4/T1) > 90% within 210 s. Sugammadex, in combination with objective neuromuscular monitoring, can be used to reverse rocuronium-induced neuromuscular blockade in patients with myasthenia gravis, thereby avoiding the need for reversal with acetylcholinesterase inhibitors. [source]

Effects of different doses of remifentanil on the end-tidal concentration of sevoflurane required for tracheal intubation in children

ANAESTHESIA, Issue 8 2009
L. He
Summary We investigated the effects of different doses of remifentanil on the end-tidal concentration of sevoflurane required for tracheal intubation in children without the use of neuromuscular blocking drugs. One hundred and thirty paediatric patients, aged 3,8 years, were randomly allocated to receive no remifentanil (group control) or remifentanil 0.1 ,g.kg,1.min,1 (group remi0.1), 0.2 ,g.kg,1.min,1 (group remi0.2), 0.3 ,g.kg,1.min,1 (group remi0.3). All patients were anaesthetised using 5% sevoflurane. After loss of eyelash reflex, remifentanil 1 ,g.kg,1 was injected over 1 min followed by an appropriate group-dependent infusion and the end-tidal sevoflurane concentration was changed. Predetermined end-tidal sevoflurane concentrations for each group were determined using the Dixon up-and-down method. After the target concentration of sevoflurane was maintained for 5 min, the child's trachea was intubated. Successful intubation was defined as excellent or good intubating conditions. The end-tidal concentration (SD) of sevoflurane for successful tracheal intubation in 50% of children (ED50) were 5.16 (0.22)% in control, 3.27 (0.18)%, 1.81 (0.20)% and 1.01 (0.11)%, in remi0.1, remi0.2, and remi0.3 groups, respectively. Using probit analysis, the 95% effective dose (ED95) of sevoflurane were 5.60% (95% CI 5.35,7.66), 3.77% (95% CI 3.45,7.74), 2.18% (95% CI 1.96,3.86), 1.19% (95% CI 1.06,1.82) in control, remi0.1, remi0.2, and remi0.3 groups, respectively. [source]

Basic principles of neuromuscular transmission

ANAESTHESIA, Issue 2009
J. A. J. Martyn
Summary Neuromuscular transmission at the skeletal muscle occurs when a quantum of acetylcholine from the nerve ending is released and binds to the nicotinic acetylcholine receptors on the postjunctional muscle membrane. The nicotinic acetylcholine receptors on the endplate respond by opening channels for the influx of sodium ions and subsequent endplate depolarisation leads to muscle contraction. The acetylcholine immediately detaches from the receptor and is hydrolysed by acetylcholinesterase enzyme. Suxamethonium is a cholinergic agonist stimulating the muscle nicotinic acetylcholine receptors prior to causing neuromuscular block. Non-depolarising neuromuscular blocking drugs bind to the nicotinic acetylcholine receptors preventing the binding of acetylcholine. Non-depolarising neuromuscular blocking drugs also inhibit prejunctional ,3,2 nicotinic acetylcholine autoreceptors, which can be seen in the clinical setting as train-of-four fade. In some pathological states such as denervation, burns, immobilisation, inflammation and sepsis, there is expression of other subtypes of nicotinic acetylcholine receptors with upregulation of these receptors throughout the muscle membrane. The responses of these receptors to suxamethonium and non-depolarising neuromuscular blocking drugs are different and explain some of the aberrant responses to neuromuscular blocking drugs. [source]

The undesirable effects of neuromuscular blocking drugs

Cyclodextrins and the emergence of sugammadex

ANAESTHESIA, Issue 2009
L. H. D. J. Booij
Summary Residual paralysis, with its subsequent postoperative pulmonary sequelae, is one of the major complications of anaesthesia, and was recognised shortly after the introduction of neuromuscular blocking drugs into routine clinical practice. Although its incidence decreased with the introduction of intermediate duration drugs, and further diminished with routine neuromuscular monitoring and reversal with cholinesterase inhibitors, residual paralysis still remained a problem. In the search for alternatives to stop the effect of neuromuscular blocking drugs and to match their duration of action to clinical need, chelation of the non-depolarising neuromuscular blocking drugs was considered. It was recognised that cyclodextrins could encapsulate steroidal molecules and thereby inactivate the aminosteroidal neuromuscular blocking drugs. In order to improve the binding of rocuronium to the cyclodextrin and to increase the compound's water solubility, the molecule was modified. This led to the development of sugammadex (Org 25969), a modified ,-cyclodextrin. The modification of the molecule and the initial in vitro studies that led to in vivo and later human studies of this conceptually new drug for anaesthesia are described. [source]

Sugammadex in clinical practice

Neuromuscular blocking drugs and their antagonists in patients with organ disease

ANAESTHESIA, Issue 2009
R. G. Craig
Summary The pharmacodynamics and pharmacokinetics of the currently available neuromuscular blocking and reversal drugs may be altered by organ disease. Adverse effects such as prolonged neuromuscular block, postoperative residual curarisation, recurarisation, the muscarinic effects of the anticholinesterases, and the side-effects of the antimuscarinics are encountered more frequently. This review will consider these potential problems and assess the role of sugammadex in enabling the anaesthetist to avoid them. It will also present the latest knowledge regarding the safety and efficacy of sugammadex in patients with renal, hepatic, cardiovascular and pulmonary disease. [source]

Clinical implications of sugammadex

ANAESTHESIA, Issue 2009
J. E. Caldwell
Summary Sugammadex is a cyclodextrin molecule that encapsulates and inactivates rocuronium and vecuronium. As a result, any degree of neuromuscular block produced by rocuronium or vecuronium can be rapidly and completely reversed without autonomic effects. Because sugammadex is optimised for reversing rocuronium it is most likely to be used in conjunction with this drug. Sugammadex will allow deep levels of block to be maintained until the very end of surgery, and will allow block to be reversed at any time after rocuronium administration, even just a few minutes. The recommended dose-range is 2,16 mg.kg-1 (ascender), depending on the level of block. The availability of sugammadex reversal may increase the use of rocuronium, and decrease the use of suxamethonium and benzylisoquinoline neuromuscular blocking drugs. In addition, it will certainly increase pharmacy costs, which may be offset by faster recovery and discharge from the post-anesthesia recovery unit. Sugammadex may also change monitoring practices in that post-tetanic count will be required to quantify deep block, and quantitative monitoring of recovery may be driven by cost concerns in order to allow the use of the smallest dose of sugammadex that gives a satisfactory train-of-four ratio. Alternatively, monitoring may essentially be abandoned since a large dose of sugammadex will reliably reverse any degree of rocuronium-induced block. The ultimate clinical utility of sugammadex will be clear only after large-scale clinical use. [source]

Laryngoscopy force in the sniffing position compared to the extension-extension position

ANAESTHESIA, Issue 4 2008
L. Lee
Summary Laryngoscopy is sometimes easier with the patient's head and neck in the extension-extension position (head extension with the neck extended by the head section of the table bent down at 30°) rather than the classical ,sniffing the morning air' position. We therefore tested the hypothesis that the axial force required for laryngoscopy is less in the extension-extension than the sniffing position. We measured the force axial to the handle of a Macintosh 3 laryngoscope in 20 subjects under general anaesthesia who had been given neuromuscular blocking drugs. Measurement of force was made in the sniffing position and the extension-extension position. The mean (SD) axial force required in the extension-extension position was lower than in the sniffing position (19.6 (7.8) N versus 23.6 (8.6) N, p = 0.04). In the setting of routine tracheal intubation, less force is required when the patient is in the extension-extension position than in the sniffing position. [source]

Prevalence of positive prick test to neuromuscular blocking drugs in the surgical population

BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 4 2006
Eduardo Tamayo
No abstract is available for this article. [source]