Incidence And Severity Of Suxamethonium Induced Fasciculation And Post-Operative Myalgia, And Their Association With Different Iv Induction Agents Among Adult Patients Underwent Elective Surgery At Jimma Medical Center, A Prospective Cohort Study
Mebratu Tila1, Zemenu Muluken2, Negashu Dadi2, Mesfin Zewude3, Elias Habtu1, Getahun Dendir1, WonduReta Demissie4*
1 Wolaita Sodo University, College of medicine and Health Sciences, School of Anesthesia, WolaitaSodo, Ethiopia.
2 Jimma University, Institute of Health, Faculty of Medical Science, School of Anesthesia, Jimma, Ethiopia.
3 Jimma University, Institute of Technology, Jimma, Ethiopia.
4 Jimma University, Institute of Health, Faculty of Medical Science, Department of Biomedical sciences, Jimma, Ethiopia.
*Corresponding Author
Wondu Reta Demissie,
Jimma University, Institute of health, Faculty of Medical Science, Department of Biomedical Sciences, Jimma, Ethiopia.
Tel: +251913988722
E-mail: majore04@gmail.com OR wondu.demissie@ju.edu.et
Received: October 09, 2020; Accepted: April 03, 2021; Published: April 30, 2021
Citation: Mebratu Tila, Zemenu Muluken, Negashu Dadi, Mesfin Zewude, Elias Habtu, Getahun Dendir, WonduReta Demissie. Incidence And Severity Of Suxamethonium Induced Fasciculation And Post-Operative Myalgia, And Their Association With Different Iv Induction Agents Among Adult Patients Underwent Elective Surgery At Jimma Medical Center, A Prospective Cohort Study. Int J Anesth Res. 2021;09(03):624-629. doi: dx.doi.org/10.19070/2332-2780-21000124
Copyright: Payal Naranbhai Patel© 2021. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.
Abstract
Background: Suxamethonium induced fasciculation (SIF) and post-operative myalgia (POM) is one the side effects occurred
following administration of suxamethonium.
Objective: The present study aimed to assess the incidence and severity of SIF and POM, and their association with different
IV induction agents among adult patients underwent elective surgery at Jimma medical center (JMC).
Methods: Prospective cohort study design was employed among a sampled 140 patients whoinduced by four IV induction
agents (propofol, thiopentone, ketamine and ketofol) where in each group 35 patients were equally distributed. SIF and POM
were assessed by separated structured grading and scoring toolsintraoperatively and post-operatively (respectively) after exposing
patients toalready mentioned four induction agents. Data was entered into Epidata version 4.3.1 and finally exported to
SPSS version 20 for further analysis. Cross tabulation/chi square and binary logistic regression were applied to determine their
association. P-value < 0.05 was declared as statistically significant.
Results: The incidence of SIF was 94.3% and differs among induction agents (non-statistically significant difference) (propofol
32(22.9%), thiopentone 34(24.3%), ketamine 33(23.6%) and ketofol 33(23.6%) (P-value=0.204). The incidence of POM
was 29.3% and highest among ketamine group 15(10.7%) and also varies among groups (propofol 6(4.3%), thiopentone
and ketofol (each10(7.1%)) (P-value=0.255). The likelihood of POM occurrence was more likely among patients induced by
ketamine [OR 1.8(0.7-5.1), p=0.215)] and thiopentone [OR 1.1(0.3-2.8), p=0.999)] but less likely among patients induced by
propofol [OR 0.5(0.1-1.6), p=0.259)] by taking patients induced by ketofol as reference. The likelihood of SIF occurrence was
also varies among IV induction agent(about two fold among thiopentone groups [OR 2.1(1.2-23), p=0.563]), but not showed
statistically significant difference among groups.
Conclusion and Recommendation: Even though, the incidence of both SIF and POM were profound and no statistically
significant safe IV inductions that mitigate this adverse effect(fasciculation and POM) following administration of suxamethonium,
other option of muscle relaxant was warranted.
2.Introduction
3.Methodology
4.Results
5.Discussions
6.Conclusion
7.Acknowledgments
8.References
Keywords
Suxamethonium Induced Fasciculation; Post-Operative Myalgia; Incidence, Severity; IV Induction Agents; JMC,
Ethiopia.
Introduction
Despite suxamethonium started to be used as one of the anesthetic
drugs for muscle relaxation with extra short onset of action
and brief duration of action since 1949, it was also accompanied
with different side effects [1, 2]. One of the profound side effect is
neuromuscular effects and muscle pain that patients experienced
at post-operative period probably due to intraoperative fasciculation
discerned or secondary to damage produced in the muscle
during fasciculation [3-6]. The possible mechanism of SIF is due
to prejunctional depolarizing action of succinylcholine, resulting
in repetitive firing of the motor nerve terminals and antidromic discharges that manifest as uncoordinated muscle contractions [7].
The phenomenon of POM was first noted in 1952 by Churchill-
Davidson following injections of succinylcholine due to diffuse
uncoordinated contractions of muscle bundles [8]. POM refers
to occasional vigor of muscle contractionsthat may give rise to a
feeling of muscular stiffness/ pain of (facial, jaw, neck, shoulder,
chest, back, trunk, limb/extremities)after consciousness has been
regained. It commonly manifested as the pain one might suffer
after strenuous physical exercise and usually affecting more than
one site that causing disability or limiting activities and difficulty
on getting out of bed or turning head postoperatively [9, 10]. It is
postulated due to increased intracellular calcium concentrations,
membrane phospholipid degradation, and release of free fatty
acids or free radicals, which lead to increased membrane permeability
[11-13].
The incidence of POM is significant and varies among patients
underwent surgery with succinylcholine. The duration of discomfort
is also highly variable among patients but, it usually appears
on the first day after surgery and lasts for 2 or 3 days, occasionally
persists for as long as a week [14-16]. POM is revealed as source
of distress to patients than surgical site wound for its unpleasant
consequences to patients’ quality of life (delayshospital admission
period, expose to unplanned expenses, prolongs time to return to
daily activity and influence individual’s productivity) [17, 18]. The
incidence of POM also varies among IV induction agents (minimal
among propofol [19, 20]) and interventional studies reported
that its incidence was minimized by pretreatment of atracurium
[21], rocuronium [22], vecuronium [23] diclofenac [24], ketorolac
[25],phenytoin [26], lidocaine [27], benzodiazepines [28], calcium
gluconate [29] and magnesium sulfate [30].
Despite, the applicability of ideal muscle relaxants that used instead
of suxamethonium in developed countries for their minimal
side effects; it is the only available and utilized short acting muscle
relaxant in the setting and considering that the incidence of fasciculation
and POM are inevitable. Thus, the present study was
aimed to sort/opt for the possible IV induction agent/s that has/
have minor side effects (SIF and POM) because it is the standard
to prevent/reduce fasciculation and POM.
Materials and Methods
The study was conducted among a total of 140 patients underwent
elective surgeryby four IV induction agents (propofol, thiopentone,
ketamine and ketofol) from August 1-September 30,
2019 at JMC. JMC islocated at Jimma zone, Oromia region at
distance of 350 km to southwest from the capital of Ethiopia,
Addis Ababa.Itis one of the pioneer teaching referral hospitals of
the country serving millions of population in the catchment area.
A prospective cohort study design was employed to assess POM
and SIF after all patients were equally exposed to different four
induction agents (propofol, thiopentone, ketamine and ketofol)
35 patients in each groupaimed to sort for the possible induction
agent/s that has/have minor side effects.
SIF was assessed intraoperatively following sux administration by
structured questionnaire for grading and scoring of fasciculation
[31, 32] and operationalized as:
Fasciculation: refers to any involuntary contraction/tremor of
skeletal muscles discerned immediately following administration
of sux.
Grade 0 fasciculation (Nil): No visible fasciculation
Grade 1(mild): Fine fasciculation of the eyes, face, neck, fingers
without movement of limbs
Grade 2(moderate): Fasciculation of greater intensity at more
than two sites or movement of
Limbs (fasciculation involving limbs and/or trunk).
Grade 3(severe): Vigorous sustained and widespread fasciculation
or fasciculations with movement of one or more limbs and/
or movements requiring forceful retention.
POM was assessed postoperatively at 24hrs by structured tools
(Postoperative Myalgia Survey (PMS) with 14-item and Postoperative
Myalgia Evaluation Scale (PMES which is a modification
of the Visual Analog Pain Scale (VAPS) with 4-Likert scale /0-3)
[33,34]and operationalized as:
POM: refers generalized aches/sores/stiffness/pains of muscles
that commonly occur within 24 hours after surgery.
Nil: No muscle pain or stiffness
Mild myalgia: Slight pain at one site but not causing disability.
Moderate myalgia: Pain at more than one site but not causing
disability
Severe myalgia: Pain at more than one site, causing disability in
turning head and standing-up.
The data was entered into Epidata version 4.3.1 and finally exported
to SPSS version 20 for further analysis. Both descriptive
statistics and analytical statistics were applied and the finding was
reported bytables/figures and narration.Binary logistic regression
was usedto assess the association ofoutcome variable (POM) with
fasciculation and IV induction agents. P value < 0.05 was considered
as statistically significant. The study was approved by ethical
review board of Jimma University and letter of permission/cooperation
was collected from school anesthesia and the hospital.
After the purposes of the study was explained to patients who
underwent elective surgery, both verbal and written consent were
taken from volunteer participants.Informationgathered from respondents
waskept confidential.
Results
Baseline characteristics of patients underwent elective surgery
A total of 140 participants were enrolled to the study with the
mean age of 36.5 +10.5 that ranged from 18-60 years, with male
to female ratio of 1:2.18. Respondents were exposed to four IV
inductions agents (each 35) intraoperatively and all relaxed by suxamethoniumas
detailed in Table 1.
Incidence of sux induced fasciculation and its severity
The incidence of fasciculation at intraoperative period following
the administration of sux was 94.3% in general where it
varies among induction agents (higher among patients induced
with thiopentone34 (24.3%)and lower among propofol group 32
(22.9%). As severity of SIF was assessed by grading and scoring
tool of fasciculation, majority of them were allocated to moderate 54(38.3%) scale. Among total of 41 patients with mild fasciculation,
majority was seen among patients induced by ketamine
15(10.7%) where the rest mild SIF was observed among thiopentone
11(7.9%), ketofol 8(5.7%) and propofol 7(5.0%). Moderate
SIF was also dominantly observed among patients induced
by propofol and ketamine (each 15(10.7%)). But, severe scale of
SIF was higher among patients induced by thiopentone 13(9.3%)
followed by ketofol 11(7.9%), propofol 10(7.1%) and ketamine
3(2.1%) as seen on (Table 2).
Incidence of POM and its severity
The incidence of POM at 24 hours of post-operative period
was 29.3% that complained for muscle pain/stiffness among 41
patients where the higher magnitude screened among patients
induced by ketamine 15(10.7%), followed by thiopentone and
ketofol (each 10 (7.1%)) while minimal among propofol group
6(4.3%. POM was also further allocated to mild 30(21.4%), moderate
10(7.1%) and severe scale 1(0.7%). Severe scale of POM was
only observed among patients induced by thiopentone (Table 3).
Association of POM with IV induction agents
The association of POM with IV induction agents was performed
by logistic regression. Despite, non-statistically significant
difference, the occurrence of POM was varied among IV induction
agents. The likelihood of POM occurrence was more likely
among patients induced by ketamine [OR 1.8(0.7-5.1), p=0.215)] and thiopentone [OR 1.1(0.3-2.8), p=0.999)] but less likely among
patients induced by propofol [OR 0.5(0.1-1.6), p=0.259)] by taking
patients induced by ketofol as referenceas detailed in Table 4.
Association of SIF with IV induction agents
The likelihood of SIF occurrence was also varies among IV induction
agent(about two fold among thiopentone groups [OR
2.1(1.2-23), p=0.563]), but not showed statistically significant difference
among groups (Table 5).
Discussions
A total of 140 respondents wereenrolled to the study with the
mean age of 36.5+10.5 that ranged from 18– 60 years who equally
exposed to four IV inductions agents(each 35) intra-operatively
and intended to assess POM within 24 hours of post-operative
period by applying prospective cohort study design.
The incidence of fasciculation at intraoperative period following
the administration of sux was 94.3% and it varies among induction
agents (higher among patients induced with thiopentone 34 (24.3%) and lowest among propofol group 32 (22.9%) probably
due to propofol effect of antioxidant like a-tocopherol and it accumulates
in the biomembranes with an ability to form stable
radicals and inhibits propagation of reactions involving free radicals
to attenuate postoperative myalgia caused by succinylcholine
[13, 35, 36]. This finding was in harmony with studiesconducted
previously [5, 13, 37, 38].
Severity of fasciculation was identified and allocated as mild
41(29.3%), moderate 54(38.6%) and severe 37(26.4%) also differs
among groups: mild fasciculation was more observed among
ketamine group 15(10.7%) and lessseen among propofol group
7(5.0%). Moderate SIF was also dominantly observed among
patients induced by propofol and ketamine (each 15(10.7%)).
But, severe scale of SIF was higher among patients induced by
thiopentone 13(9.3%) followed by ketofol 11(7.9%), propofol
10(7.1%) and ketamine 3(2.1%). This pattern was also supported
by previous studies [39, 40]. Among total of 41 patients with
mild fasciculation, majority was seen among patients induced by
ketamine 15(10.7%) where the rest mild SIF was observed among
thiopentone 11(7.9%), ketofol 8(5.7%) and propofol 7(5.0%).
The incidence of POM was 29.3% in general and varies among
IV induction agents (highest ketamine 15(10.7%), followed by
thiopentone and ketofol (each 10 (7.1%)) while minimal among
propofol group 6(4.3%.This finding was also supported by other
studies [13, 37-40].
In comparable with present finding, the study conducted by Mc-
Clymont to compare POM among thiopentone and propofol
reported that the propofol group had a significantly lower incidenceof
suxamethonium myalgia (19%) compared with the thiopentone
group (63%) (P<O.05) [41].
Even though, there is no statistically significant difference in the
occurrence of POM, the present study revealed dominance of
POM among ketamine group. But, Previous studies reported less
incidence among ketamine due to ketamine effects of both antinociceptive
and pronociceptive actions via NMDA receptor and
aminergic (serotonergic and noradrenergic) receptors and possible
interferes with nicotinic, muscarinic, monoaminergic and
opioid receptors in abolishing pain [42]. The study conducted by
Nasseri and Arvien that compared ketofol and propofolwas also
reported high incidence of POM among propofol group than ketofol
group against our finding [43]. Thus, further studies with
large sample and strong design will be inspired to mediate the
existing findings.
Conclusion
Even though, the incidence of both SIF and POM were profound
and there is no statistically significant safe IV inductions that mitigate
this adverse effect (fasciculation and POM) following administration
of suxamethonium, other option of muscle relaxant was
warranted/inspired at the setting and the country at all.
Acknowledgments
We would like to thank Jimma University for providing financial
support and also extend our heartfelt gratitude to patients involved
in the study.
References
- FOLDES FF, MCNALL PG, BORREGO-HINOJOSA JM. Succinylcholine: a new approach to muscular relaxation in anesthesiology. N Engl J Med. 1952 Oct 16;247(16):596-600. Pubmed PMID: 12993276.
- BOURNE JG, COLLIER HO, SOMERS GF. Succinylcholine (succinoylcholine), muscle-relaxant of short action. Lancet. 1952 Jun 21;1(6721):1225-9. Pubmed PMID: 14939768.
- O'Sullivan EP, Williams NE, Calvey TN. Differential effects of neuromuscular blocking agents on suxamethonium-induced fasciculations and myalgia. Br J Anaesth. 1988 Mar;60(4):367-71. Pubmed PMID: 3281700.
- GORDH T, WAHLIN A. Potentiation of the neuromuscular effect of succinylcholine by tetrahydro-amino-acridine. Acta Anaesthesiol Scand. 1961;5:55-61. Pubmed PMID: 13707131.
- Wong SF, Chung F. Succinylcholine-associated postoperative myalgia. Anaesthesia. 2000 Feb;55(2):144-52. Pubmed PMID: 10651675.
- Shafy SZ, Hakim M, Krishna SG, Tobias JD. Succinylcholine-Induced Postoperative Myalgia: Etiology and Prevention. Journal of Medical Cases. 2018 Jul 19;9(8):264-6.
- Hartman GS, Fiamengo SA, Riker WF Jr. Succinylcholine: mechanism of fasciculations and their prevention by d-tubocurarine or diphenylhydantoin. Anesthesiology. 1986 Oct;65(4):405-13. Pubmed PMID: 3767039.
- CHURCHILL-DAVIDSON HC. Suxamethonium (succinylcholine) chloride and muscle pains. Br Med J. 1954 Jan 9;1(4853):74-5. Pubmed PMID: 13106475.
- Brodsky JB, Ehrenwerth J. Postoperative muscle pains and suxamethonium. Br J Anaesth. 1980 Feb;52(2):215-8. Pubmed PMID: 7362724.
- Turan A, Mendoza ML, Gupta S, You J, Gottlieb A, Chu W, et al. Consequences of succinylcholine administration to patients using statins. Anesthesiology. 2011 Jul;115(1):28-35. Pubmed PMID: 21606827.
- McLoughlin C, Elliott P, McCarthy G, Mirakhur RK. Muscle pains and biochemical changes following suxamethonium administration after six pretreatment regimens. Anaesthesia. 1992 Mar;47(3):202-6. Pubmed PMID: 1566986.
- Raman SK, San WM. Fasciculations, myalgia and biochemical changes following succinylcholine with atracurium and lidocaine pretreatment. Can J Anaesth. 1997 May;44(5 Pt 1):498-502. Pubmed PMID: 9161744.
- Maddineni VR, Mirakhur RK, Cooper AR. Myalgia and biochemical changes following suxamethonium after induction of anaesthesia with thiopentone or propofol. Anaesthesia. 1993 Jul;48(7):626-8. Pubmed PMID: 8346781.
- . Morris DD, Dunn CH. Suxamethonium chloride administration and postoperative muscle pain. British medical journal. 1957 Feb 16;1(5015):383.
- Newnam PT, Loudon JM. Muscle pain following administration of suxamethonium: the aetiological role of muscular fitness. Br J Anaesth. 1966 Jul;38(7):533-40. Pubmed PMID: 5943809.
- Allen TK, Habib AS, Dear GL, White W, Lubarsky DA, Gan TJ. How much are patients willing to pay to avoid postoperative muscle pain associated with succinylcholine? J Clin Anesth. 2007 Dec;19(8):601-8. Pubmed PMID: 18083474.
- Wu CL, Rowlingson AJ, Partin AW, Kalish MA, Courpas GE, Walsh PC, et al. Correlation of postoperative pain to quality of recovery in the immediate postoperative period. Reg Anesth Pain Med. 2005 Nov-Dec;30(6):516-22. Pubmed PMID: 16326335.
- Rawal N. Postoperative pain treatment for ambulatory surgery. Best Pract Res Clin Anaesthesiol. 2007 Mar;21(1):129-48. Pubmed PMID: 17489224.
- McClymont C. A comparison of the effect of propofol or thiopentone on the incidence and severity of suxamethonium-induced myalgia. Anaesthesia and intensive care. 1994 Apr;22(2):147-9.
- Kararmaz A, Kaya S, Turhanoglu S, Ozyilmaz MA. Effects of high-dose propofol on succinylcholine-induced fasciculations and myalgia. Acta Anaesthesiol Scand. 2003 Feb;47(2):180-4. Pubmed PMID: 12631047.
- Shabanian G, Shabanian M, Shabanian A, Heidari-Soureshjani S. Comparison of atracurium and methocarbamol for preventing succinylcholineinduced muscle fasciculation: A randomized controlled trial. J Adv Pharm Technol Res. 2017 Apr-Jun;8(2):59-62. Pubmed PMID: 28516057.
- Abbas N, Tariq S, Khan AW, Murtaza G, Naqvi N, Khanzada A. To asses the effects of rocuronium pretreatment on succinylcholine induced fasciculations and postoperative myalgias. J Pak Med Assoc. 2009 Dec;59(12):847- 50. Pubmed PMID: 20201179.
- Kim JH, Cho H, Lee HW, Lim HJ, Chang SH, Yoon SM. Comparison of rocuronium and vecuronium pretreatment for prevention of fasciculations, myalgia and biochemical changes following succinylcholine administration. Acta Anaesthesiol Sin. 1999 Dec;37(4):173-8. Pubmed PMID: 10670114.
- Pandey CK, Karna ST, Tandon M, Pandey VK, Singh A. Comparative evaluation of prophylactic use of pregabalin, gabapentin and diclofenac sodium for prevention of succinylcholine-induced myalgia: a randomized, doubleblinded study. J Postgrad Med. 2014 Jan-Mar;60(1):16-20. Pubmed PMID: 24625934.
- Leeson-Payne CG, Nicoll JM, Hobbs GJ. Use of ketorolac in the prevention of suxamethonium myalgia. Br J Anaesth. 1994 Dec;73(6):788-90. Pubmed PMID: 7880667.
- Hatta V, Saxena A, Kaul HL. Phenytoin reduces suxamethonium-induced myalgia. Anaesthesia. 1992 Aug;47(8):664-7. Pubmed PMID: 1519714.
- Usubiaga JE, Wikinski JA, Usubiaga LE, Molina F. Intravenous lidocaine in the prevention of postoperative muscle pain caused by succinylcholine administration. Anesth Analg. 1967 Mar-Apr;46(2):225-30. Pubmed PMID: 6066978.
- Eisenberg M, Balsley S, Katz RL. Effects of diazepam on succinylcholineinduced myalgia, potassium increase, creatine phosphokinase elevation, and relaxation. Anesth Analg. 1979 Jul-Aug;58(4):314-7. Pubmed PMID: 572176.
- Shrivastava OP, Chatterji S, Kachhawa S, Daga SR. Calcium gluconate pretreatment for prevention of succinylcholine-induced myalgia. Anesth Analg. 1983 Jan;62(1):59-62. Pubmed PMID: 6849511.
- Kumar M, Talwar N, Goyal R, Shukla U, Sethi A. Effect of magnesium sulfate with propofol induction of anesthesia on succinylcholine-induced fasciculations and myalgia. J Anaesthesiol Clin Pharmacol. 2012 Jan;28(1):81- 5. Pubmed PMID: 22345952.
- Yun MJ, Kim YH, Go YK, Shin JE, Ryu CG, Kim W, et al. Remifentanil attenuates muscle fasciculations by succinylcholine. Yonsei Med J. 2010 Jul;51(4):585-9. Pubmed PMID: 20499427.
- FOSTER CA. Muscle pains that follow administration of suxamethonium. Br Med J. 1960 Jul 2;2(5191):24-5. Pubmed PMID: 13824106.
- Campbell TL. A comparison of the differential effects of atracurium and/or lidocaine on succinylcholine-induced postoperative myalgia.
- WHITE DC. Observations on the prevention of muscle pains after suxamethonium. Br J Anaesth. 1962 May;34:332-5. Pubmed PMID: 14006507.
- Garg K, Luthra N, Sud S, Kaul TK. Effect of repeat bolus dose of propofol on succinylcholine-induced fasciculations and myalgia. Journal of Mahatma Gandhi Institute of Medical Sciences. 2014 Jul 1;19(2):106.
- Murphy PG, Myers DS, Davies MJ, Webster NR, Jones JG. The antioxidant potential of propofol (2,6-diisopropylphenol). Br J Anaesth. 1992 Jun;68(6):613-8. Pubmed PMID: 1319189.
- OMOSANYA AA. A COMPARISON OF THE EFFECT OF HIGH DOSE PROPOFOL, STANDARD DOSE PROPOFOL AND SODIUM THIOPENTONE IN THE PREVENTION OF SUXAMETHONIUM INDUCED FASCICULATION AND MYALGIA. Faculty of Anaesthesia. 2018 Sep 15.
- Schreiber JU, Lysakowski C, Fuchs-Buder T, Tramèr MR. Prevention of succinylcholine-induced fasciculation and myalgia: a meta-analysis of randomized trials. Anesthesiology. 2005 Oct;103(4):877-84. Pubmed PMID: 16192781.
- Abebe G. Assessment on Maginitude and Associated Factors on Suxamethoneum Induced Post Operative Myalgia in Adult Elective Surgical Patients From January 1, 2017 To March 1, 2017 At Zewuditu Memorial Hospital, Addis Ababa. Cross Sectional Study. PhD Thesis.Addis Abeba University, 2017.
- Hika A. Effect of propofol versus thiopentone sodium as an induction agent on prevention of succinylcholine induced fasciculation and myalgia: prospective cohort study. PhD Thesis. Addis Ababa Universty, 2018.
- McClymont C. A comparison of the effect of propofol or thiopentone on the incidence and severity of suxamethonium-induced myalgia. Anaesth Intensive Care. 1994 Apr;22(2):147-9. Pubmed PMID: 8210016.
- Dahan A, Olofsen E, Sigtermans M, Noppers I, Niesters M, Aarts L, et al. Population pharmacokinetic-pharmacodynamic modeling of ketamineinduced pain relief of chronic pain. Eur J Pain. 2011 Mar;15(3):258-67. Pubmed PMID: 20638877.
- Nasseri K, Arvien S. Effects of low-dose ketamine on succinylcholine-induced postoperative myalgia in outpatient surgeries: a randomized, doubleblind study. J Pain Res. 2016 Jul 6;9:503-8. Pubmed PMID: 27462175.