Unanticipated Consequences of Switching to Sugammadex: Anesthesia Provider Survey on the Hormone Contraceptive Drug Interaction.

BACKGROUND: Sugammadex binds progesterone with high affinity and may interfere with hormonal contraceptive effectiveness. The clinical, economical, and ethical implications of unintended pregnancy should prompt anesthesiologists to actively consider and manage this pharmacologic interaction. We surveyed anesthesiology providers at our institution about knowledge of this potential adverse drug interaction, how they manage it clinically, and the extent to which they involve patients in shared decision-making regarding choice of neuromuscular blocker antagonist. METHODS: A survey instrument was distributed to anesthesiology providers at a large, tertiary-care medical center. The survey explored prior experience using neostigmine and sugammadex, knowledge about potential sugammadex interference with hormonal contraception, pre-/postoperative counseling practices, clinical management, and shared decision-making regarding potential use of neostigmine in lieu of sugammadex to avoid this drug-drug interaction. RESULTS: Of 259 surveys distributed, 155 were fully completed, and 10 were partially completed. Overall response rate was 60% (residents 85%, student nurse anesthetists 53%, certified registered nurse anesthetists 58%, attendings 48%). All but 1 respondent recognized the potential for sugammadex interference with oral hormonal contraception. Far fewer accurately identified potential interference with hormonal intrauterine devices (44%) and hormonal contraceptive implants (55%). The manufacturer's recommended 7-day duration of alternative contraception was correctly identified by 72% of respondents; others (22%) reported longer durations (range 10-30 days). Most (78% overall) agreed/strongly agreed that potential interference with contraceptive effectiveness should be discussed with patients preoperatively. Despite the majority (86% overall) that endorsed shared decision-making and inviting patient input regarding choice between sugammadex and neostigmine, many respondents reported "rarely/never" having discussed this drug interaction with patients in actual clinical practice, either preoperatively (67%) or postoperatively (80%). Furthermore, most respondents (79%) reported "rarely/never" administering neostigmine to intentionally avoid this drug interaction. CONCLUSIONS: Two years after designating sugammadex as antagonist of choice, physician and nurse anesthesia providers reported seldom inquiring about contraceptive use among women of childbearing potential and rarely discussing potential risk of contraceptive failure from sugammadex exposure. Most lack accurate knowledge of sugammadex interference with hormonal intrauterine and subcutaneous contraceptive devices. Although most endorse preoperative counseling and support patient autonomy or shared decision-making regarding choice of reversal agent, the same respondents report rarely, if ever, actualizing these positions in clinical practice. These conflicting findings highlight the need for education regarding residual neuromuscular block versus adverse drug interactions, collaboration among providers involved in patient counseling, and intentional mindfulness of reproductive justice when caring for women of childbearing potential.

Protection by Mikania laevigata (guaco) extract against the toxicity of Philodryas olfersii snake venom.

Philodryas olfersii is responsible for most colubrid snakebites in Brazil. In this work, we examined the ability of an ethanolic extract from Mikania laevigata (guaco) leaves to protect against the in vitro neuromuscular activity of P. olfersii venom in mouse phrenic nerve-diaphragm (PND) and chick biventer cervicis (BC) preparations. M. laevigata extract caused moderate twitch-tension facilitation at low concentrations (107.4 ± 6.2% with 20 µl/ml and 118.9 ± 9.3% with 40 µl/ml in PND, and 120.7 ± 7.7% with 40 µl/ml and 114.5 ± 4.4% with 50 µl/ml in BC after 120 min; n = 4-6, mean ± SEM). In PND, the ethanol alone (40 µl/ml, n = 4) did not change the twitch-tension when compared with control. However, in BC, the ethanol produced a higher facilitation when compared to control. At higher concentrations (>50 µl/ml) the extract caused total and reversible blockade in both preparations. Venom (50 µg/ml) caused partial blockade in PND (58.5 ± 12%, n = 4) and almost total blockade in BC (93.5 ± 2.2%, n = 4). Pretreatment of the preparations with extract (40 µl/ml) for 30 min before incubation with venom (50 µg/ml) completely protected PND from neuromuscular blockade and delayed the blockade in BC. The extract alone caused only mild morphological alterations (12.5 ± 0.5% and 10.9 ± 2.3% fiber damage in PND and BC, respectively, compared to 2.3 ± 0.3% and 3 ± 0 in controls; n = 3), with no increase in expression of the inflammatory cytokines TNFα and IFNγ. The ethanol alone also caused slight muscle damage: 4.3 ± 2.4% in PND and 6.7 ± 3.3% in BC (both n = 3) and little or no TNFα and IFNγ expression in both preparations as observed in control. Venom (50 µg/ml) caused 53.5 ± 8.5% and 55.8 ± 4.3% fiber damage in PND and BC, respectively; (n = 3, p < 0.05 vs. controls) and enhanced expression of TNFα and IFNγ. Pretreatment of the preparations with extract protected against venom-induced muscle damage by 80.3 and 60.4 in PND and BC, respectively, and prevented TNFα and IFNγ expression. These results indicate that the M. laevigata extract protected nerve-muscle preparations against the myotoxic, neurotoxic and inflammatory effects of P. olfersii venom.

Cysteine reversal of the novel neuromuscular blocking drug CW002 in dogs: pharmacodynamics, acute cardiovascular effects, and preliminary toxicology.

BACKGROUND: CW002 is a neuromuscular blocking drug that is inactivated by endogenous L-cysteine. This study determined the exogenous L-cysteine dose-response relationship for CW002 reversal along with acute cardiovascular effects and organ toxicity in dogs. METHODS: Six dogs were each studied four times during isoflurane-nitrous oxide anesthesia and recording of muscle twitch, arterial pressure, and heart rate. CW002 (0.08 mg/kg or 9 x ED95) was injected, and the time to spontaneous muscle recovery was determined. CW002 was then administered again followed 1 min later by 10, 20, 50, or 100 mg/kg L-cysteine (1 dose/experiment). After twitch recovery, CW002 was given a third time to determine whether residual L-cysteine influenced duration. Preliminary toxicology was performed in an additional group of dogs that received CW002 followed by vehicle (n = 8) or 200 mg/kg L-cysteine (n = 8). Animals were awakened and observed for 2 or 14 days before sacrificing and anatomic, biochemical, and histopathologic analyses. RESULTS: L-cysteine at all doses accelerated recovery from CW002, with both 50 and 100 mg/kg decreasing median duration from more than 70 min to less than 5 min. After reversal, duration of a subsequent CW002 dose was also decreased in a dose-dependent manner. Over the studied dose range, L-cysteine had less than 10% effect on blood pressure and heart rate. Animals receiving a single 200-mg/kg dose of L-cysteine showed no clinical, anatomic, biochemical, or histologic evidence of organ toxicity. CONCLUSION: The optimal L-cysteine dose for rapidly reversing the neuromuscular blockade produced by a large dose of CW002 in dogs is approximately 50 mg/kg, which has no concomitant hemodynamic effect. A dose of 200 mg/kg had no evident organ toxicity.

Piperine, the main alkaloid of Thai black pepper, protects against neurodegeneration and cognitive impairment in animal model of cognitive deficit like condition of Alzheimer's disease.

Recently, numerous medicinal plants possessing profound central nervous system effects and antioxidant activity have received much attention as food supplement to improve cognitive function against cognitive deficit condition including in Alzheimer's disease condition. Based on this information, the effect of piperine, a main active alkaloid in fruit of Piper nigrum, on memory performance and neurodegeneration in animal model of Alzheimer's disease have been investigated. Adult male Wistar rats (180-220 g) were orally given piperine at various doses ranging from 5, 10 and 20mg/kg BW at a period of 2 weeks before and 1 week after the intracerebroventricular administration of ethylcholine aziridinium ion (AF64A) bilaterally. The results showed that piperine at all dosage range used in this study significantly improved memory impairment and neurodegeneration in hippocampus. The possible underlying mechanisms might be partly associated with the decrease lipid peroxidation and acetylcholinesterase enzyme. Moreover, piperine also demonstrated the neurotrophic effect in hippocampus. However, further researches about the precise underlying mechanism are still required.

Reversal by suramin of neuromuscular block produced by pancuronium in the anaesthetized rat.

1. Rats were anaesthetized with sodium pentobarbitone and maximal twitches of a tibialis anterior muscle were evoked by stimulation of the motor nerve. 2. Suramin, injected intravenously in a series of cumulative bolus doses, each 15 mg kg-1, completely reversed a 90% depression of twitches maintained by a continuous intravenous infusion of pancuronium. The cumulated dose necessary to restore twitches to 50% of their control amplitude was 35 mg kg-1. Suramin did not modify a similar degree of block produced by suxamethonium, nor did it affect the amplitude of control maximal twitches, even in cumulative doses up to 150 mg kg-1. 3. The effects of bolus doses of suramin (85 mg kg-1), neostigmine (0.03 mg kg-1) and 4-aminopyridine (1.2 mg kg-1), calculated to restore pancuronium-blocked twitches to 95% of control amplitude, were compared. Suramin produced the most rapid reversal (1.1 +/- 0.5 min), but its duration of action was the shortest (9.4 +/- 1.6 min). Suramin was without effect on heart rate or blood pressure in the doses used. 4. The results showed that suramin reversed neuromuscular block produced by nondepolarizing blocking drug, pancuronium, but was without effect on a block produced by the depolarizing blocking drug, suxamethonium. Its short duration of action suggests that suramin would probably not be of value clinically as a reversal agent. However, it is possible that it might serve as a starter compound for the synthesis and development of a new class of reversal agents for use in anaesthetic practice.

Recovery times following edrophonium and neostigmine reversal of pancuronium, atracurium, and vecuronium steady-state infusions.

The ability of edrophonium and neostigmine to antagonize nondepolarizing neuromuscular blockade produced by steady-state infusions of atracurium, pancuronium, and vecuronium was studied in 71 adult patients anesthetized with nitrous oxide and halothane. Infusion rates of blocking drugs were adjusted so that single twitch depression as measured by the evoked integrated EMG of the hypothenar muscles was kept at 10% of control. Two minutes after the termination of the infusion either edrophonium (0.75 mg/kg) or neostigmine (0.05 mg/kg) was administered. Single twitch depression and train-of-four (T4/T1) fade was recorded during the recovery period. T4/T1 fade ratios observed at 20 min postreversal were 0.80 (atracurium-edrophonium); 0.76 (vecuronium-edrophonium); 0.44 (pancuronium-edrophonium); 0.95 (atracurium-neostigmine); 0.89 (vecuronium-neostigmine); and 0.68 (pancuronium-neostigmine). Under conditions of this study neostigmine produced more rapid and complete recovery than did edrophonium. Although edrophonium produced adequate antagonism of atracurium if 20-30 min were allowed to elapse, edrophonium reversal of pancuronium was rarely acceptable even at 30 min. Increasing the dose of edrophonium to 1.0 mg/kg produced single twitch values of 0.90 at 5 min postreversal but did not increase the rate of recovery of the train-of-four fade ratio. Neostigmine reversal of pancuronium, on the other hand, generally produced T4/T1 ratios of greater than 0.70 in 20-30 min. Although the pattern of recovery seen after reversal of vecuronium was in general quite similar to that seen after atracurium, two patients in the vecuronium-edrophonium group showed delayed recovery and also failed to respond significantly to subsequent doses of neostigmine.(ABSTRACT TRUNCATED AT 250 WORDS)

Vecuronium in the myasthenic patient.

The use of vecuronium in six patients with myasthenia gravis undergoing thymectomy is described the train-of-four twitch technique was used to monitor neuromuscular function. The first two patients received an initial dose of 0.02 mg/kg and incremental doses of 4 micrograms/kg, which is in the order of one fifth of that normally used. Satisfactory depression of the first twitch of the train-of-four, however was not obtained and, therefore, in the remaining four patients the doses were doubled. At this dose satisfactory depression of the first twitch was achieved. Neostigmine 5.0 mg produced adequate reversal of residual neuromuscular blockade and the train-of-four twitch response recovered to normal levels. With reduced dosage and with careful neuromuscular monitoring, vecuronium can be used safely in the myasthenic patient.

Use of atracurium and vecuronium in patients with oesophageal varices.

The effects of atracurium (initial dose 0.5 mg kg-1; incremental doses 0.2 mg kg-1) and vecuronium (initial dose 0.1 mg kg-1; incremental doses 0.04 mg kg-1) are described in patients with portal hypertension and some degree of liver dysfunction, and the findings compared with those from normal patients. With these doses there was no evidence of gross resistance to the two neuromuscular blockers in the patients with liver problems, although the duration of action of the initial dose was somewhat shorter, and the same may have been true of incremental doses. The method of elimination would suggest that atracurium may be the better drug in patients with severe liver dysfunction, but the use of small doses of vecuronium is not contraindicated in this type of patient.

Pharmacokinetics and pharmacodynamics of 4-aminopyridine in anesthetized dogs.

The pharmacokinetics and pharmacodynamics of 4-aminopyridine (4-AP), a drug which antagonizes nondepolarizing neuromuscular blockade, were studied in seven anesthetized dogs. Using a constant infusion of pancuronium, force of the anterior tibialis contraction in response to stimulation of the sciatic nerve was depressed to 10% of the control tension (90% depression of twitch tension). After 20 min of steady state, 4-AP (1.0 mg/kg) was administered i.v. Serum, urine and bile samples were analyzed for 4-AP concentration at several intervals for 10 hr after administration of 4-AP, using a sensitive high-performance liquid chromatographic assay (1 ng/ml). Serum data best fit a three-compartment pharmacokinetic model. The volume of the central compartment was 412 +/- 352 ml/kg (mean +/- S.D.) and the volume of distribution at steady state was 2517 +/- 363 ml/kg. Initial half-lives were 1.1 +/- 0.7 and 25.4 +/- 11 min. The terminal elimination half-life was 125 +/- 23 min and total clearance was 21 +/- 4 ml/kg/min. Of the injected dose, 60 +/- 9% was recovered in the urine and only 0.01 +/- 0.01% of the dose was recovered in the bile in 10 hr. Inasmuch as renal clearance of 4-AP exceeded glomerular filtration rate we conclude that 4-AP undergoes tubular secretion into the urine. The pharmacodynamic results included an onset time of 14 +/- 8 min, peak effect (maximum percentage of antagonism of twitch tension depression) 97 +/- 27% and duration of action 219 +/- 54 min. We conclude that 4-AP has a longer serum elimination half-life and a longer and more variable duration of action than other antagonists (i.e., neostigmine and pyridostigmine) of nondepolarizing neuromuscular blockade.

Antagonism of org NC 45 (vecuronium) and pancuronium neuromuscular blockade by neostigmine.

The antagonism, by neostigmine, of neuromuscular blockade produced by either Org NC 45 or pancuronium was studied in 29 anaesthetized patients during a continuous infusion of the myoneural blocker. The ED50 of neostigmine (dose which produced a 50% antagonism) when antagonizing Org NC 45 and pancuronium was 0.011 mg kg-1 and 0.010 mg kg-1 respectively. The dose-response relationships for the antagonism of Org NC 45 and pancuronium neuromuscular blockades were not significantly different. The duration of the effect of neostigmine was not different when antagonizing an Org NC 45- or pancuronium-induced blockade. We concluded that Org NC 45 and pancuronium are effectively and equally (independent of pharmacokinetics) antagonized by neostigmine in man.

Clinical pharmacology of ORG NC45 (NorcuronTM): a new nondepolarizing muscle relaxant.

To determine the neuromuscular effects of a new muscle relaxant, ORG NC45 (Norcuron), a monoquaternary homologue of pancuronium, 84 ASA Class I or II patients were studied under halothane and nitrous oxide anesthesia. The ED50 (dose of muscle relaxant causing a 50% depression of twitch tension) of pancuronium and ORG NC45 was 0.022 mg/kg (r = 0.90) and 0.015 mg/kg (r =0.80), respectively, for a potency ratio of 1.5 (0.022/0.015). The duration of action (time from injection to 90% recovery of control twitch tension) was 27 +/- 5 min with ORG NC45, 0.02 mg/kg, and 65 +/- 16 min with pancuronium in an equivalent dose of 0.03 mg/kg. The increase in duration of neuromuscular blockade from repetitive doses was greater with pancuronium than with ORG NC45. Reversal of an ORG NC45 neuromuscular blockade was accomplished with doses of neostigmine slightly less than those required for pancuronium. Under thiopental-nitrous oxide anesthesia, endotracheal intubation was easily performed using ORG NC45, 0.07-0.14 mg/kg. The duration of action of ORG NC45, 0.07 mg/kg, was about one-third that of pancuronium (0.1 mg/kg). It was concluded that ORG NC45 is more potent and has a shorter duration of action with both initial and repetitive doses than does pancuronium. With these characteristics and the reported lack of cardiovascular effects, the authors believe further clinical trials are warranted.

Antagonism of Org NC 45 neuromuscular blockade by neostigmine, pyridostigmine, and 4-aminopyridine.

The antagonism of Org NC 45 neuromuscular blockade by neostigmine, pyridostigmine, 4-aminopyridine, and their combinations was studied in the in vivo rat sciatic nerve anterior tibialis preparation using the constant infusion of Org NC 45 technique. The ED50 (dose of drug which produced a 50% antagonism) of neostigmine, pyridostigmine, and 4-aminopyridine were 14.5, 75, and 466 micrograms/kg, respectively. The addition of 100 microgram/kg of 4-aminopyridine, which produced no antagonism by itself, decreased neostigmine ED50 to 9.8 micrograms/kg. The addition of 200 micrograms/kg of 4-aminopyridine, which produced a 14.8% antagonism by itself, decreased the ED50 of pyridostigmine to 17.5 micrograms/kg. We concluded that neostigmine, pyridostigmine, and 4-aminopyridine effectively antagonize an Org NC 45 neuromuscular blockade. Neostigmine and pyridostigmine interact with 4-aminopyridine in a synergistic manner. The doses of antagonists were very similar to those required to antagonize a pancuronium neuromuscular blockade.

[Tetanus-Myomechanographic measurement of receptor liberation by pyridostigmine in neuromuscular block produced by d-tubocurarine, gallamine, pancuronium or alcuronium (author's transl)]. / Tetanusmyomechanographische Bestimmung der Rezeptorbefreiung durch Pyridostigmin bei neuromuskulärer Blockade mit d-Tubocurarin, Gallamin, Pancuronium oder Alcuronium.

In 48 patients anaesthetized with nitrous oxide-oxygen and hexobarbitone the neuromuscular (n-m) block (greater than or equal to 95% depression) produced by roughly equipotent doses of d-tubocurarine (dTC), gallamine (GALL), pancuronium (PANC) or alcuronium (ALC), respectively, was antagonized by 10 mg of pyridostigmine (P) applied intravenously 35-460 min after the relaxant at variable levels of spontaneous recovery from n-m block. Muscular reactions to tetanic stimulation (30 to 400 Hz, 4-5 s each) of the ulnar nerve transmitted by a force-displacement system served as a measure for calculating the relative amount of n-m receptors liberated from relaxant molecules. Within 3-10 min after its injection P increased the number of relaxant-free n-m receptors by 16 +/- 6% (M +/- SD). Thereafter recovery progressed at similar speed as before. Reinjections of 5-10 mg P were comparably as effective as the first injection. No correlations were to be found between the effectiveness of P and the dose of relaxant applied (r = 0,12 to 0,27), the level of recovery reached before P (r = 0,32), or the time at which P was injected after the relaxant (r = -0,39), respectively. However, the amount of receptors liberated by P decreased with increasing recovery from n-m block and with increasing time interval between the relaxant and the antidote injection. P was significantly more effective (P less than 0,01), when applied within 150 min after the relaxant than at applications after that time. The relative number of receptors liberated by this drug was insignificantly larger in the PANC-and GALL-block than in the ALC-and dTC-block.

Pharmacology and use of muscle relaxants in infants and children.

Succinylcholine is a short-acting depolarizing neuromuscular blocker used to facilitate intubation; pancuronium is a longer-acting, nondepolarizing agent commonly employed to control ventilation in pediatric patients. The neuromuscular block produced by both drugs may be modified by patient age, acid-base and electrolyte status, body temperature, and drugs such as aminoglycoside antibiotics; adjustment in dose or in technique of administration may be required. Cardiovascular side-effects, primarily arrhythmias, are occasionally associated with the use of either agent. In contrast to that of succinylcholine, the paralysis from pancuronium is pharmacologically reversible with the combination of atropine and neostigmine.

The antagonism of the neuromuscular blocking action of D-Tubocurarome, chloride, succinylcholine chloride and pancuronium bromide by anacardium occidentale

The cardiovascular and antiarrhythmic effects of purified extract of the inner bark of Anacardium Occidentale (cashew tree) have been documented. The antiarrhythmic effect was shown to be due to myoinositol of which the bark contains 25 percent w/w. With the exception of succinylcholine chloride, both d-tubocurarine chloride and pancuronium bromide are potent non-depolarising neuromuscular blocking agents. It is an accepted fact that there is no satisfactory antagonist for the depolarising blocking drugs such as succinycholine chloride. It was interesting to note that anacardium occidentale (AO) blocked the action of all 3 drugs on the rat phrenic-nerve-diaphragm neuromuscular preparation. A total dose of 1mg in a 50ml organ bath blocks the action of 100ug of d-tubocurarine 200ug of succinylcholine chloride and 200ug of pancuronium bromide. Pancuronium bromide is about 5 times as potent as d-tubocurarine chloride. These results indicate that AO is more effective against pancuronium. A graphical representation of the result showed that the antagonism against these 3 drugs is competitive. The onset of action of AO is slow and each dose was allowed to act for 5 minutes before the additioin of the agonist. The non-depolarising drugs are antagonised by acetylcholine and the anti-cholinesterases, but preliminary experiments showed that AO had no acetylcholine nor anticholinesterase properties. The findings indicate that there may be some other mechanism of action of non-depolarising blocking drugs than occupation of the nicotinic receptors on the motor and plate (AU)