Skip to main content

Comparison of the effects of amantadine and ondansetron in treatment of fatigue in patients with multiple sclerosis



Multiple sclerosis (MS) is a common neurological disorder with a variety of manifestations including fatigue. Fatigue may interfere with daily work and activities. Different pharmacological and non-pharmacological methods have been used for treatment of this symptom in MS patients. In this study, the effect of ondansetron and amantadine in the treatment of fatigue was compared.


In this randomized clinical trial, 53 MS patients with fatigability were enrolled (mean age ± standard deviation: 54.00 ± 7.88, Female/male ratio: 45/8). Patients were referred to Imam Clinic and Sina Hospital, Hamadan, Iran. Patients were assessed using the Fatigue Severity Scale (FSS) questionnaire. Patients were randomly assigned to either the amantadine or ondansetron treatment groups and received treatments in a crossover manner. The severity of fatigue was measured using FSS questionnaire in four stages (beginning and end of each regimen). Data were analyzed using SPSS software version 16.


The mean and standard deviation of patients’ fatigue scores before treatment were 43.07 ± 10.36 and 43.22 ± 9.67 in the amantadine and ondansetron group, respectively. These scores were 37.36 ± 7.87 and 40.00 ± 8.94 after treatment in the amantadine and ondansetron group, respectively. Both drugs significantly decreased the fatigue severity of patients (P < 0.001). There was no statistically significant difference between two regimens in terms of the mean score of fatigue before and after treatment and the frequency of complications. However, when ranking the severity of fatigue (mild, moderate, severe), fatigue reduction after intervention in the amantadine group was significantly higher than ondansetron (P = 0.026).


Both amantadine and ondansetron reduce fatigue in MS patients, but the efficacy of amantadine in reducing the MS-associated fatigue is greater than that of ondansetron.


Multiple sclerosis (MS) is a demyelinating disorder of central nervous system which affects more than 2.5 million persons in the world [1]. The disease has a relapsing–remitting nature. Common therapeutic options for MS can reduce the incidence of relapses and formation of plaques. Yet, these therapeutic methods fail to ameliorate established brain lesions or chronic symptoms including fatigue, which is a frequent observed symptom in all MS subtypes [1]. Fatigue compromises all four domains of quality of life namely physical health, psychological, environmental, and social relationships in MS patients [2]. The decreased quality of life due to fatigue is independent of MS-associated depression or debility [3]. In several patients, fatigue is stated as the single most incapacitating symptom, even more than pain and physical debility [4]. Fatigue is scored based on different scales including fatigue severity sale (FSS) [5]. Numerous pharmacological and non-pharmacological strategies have been developed for amelioration of this MS-associated symptom [6]. Amantadine as an antiviral drug is one of the suggested interventions for management of fatigue. Although not clearly defined, amantadine might affect MS-associated fatigue through its antiviral function, immune-mediated mechanism, or an amphetamine-like activity [7]. A double-blind crossover trial in MS patients has shown decreases in FSS following treatment with both amantadine and aspirin with no significant inter-group difference [8]. Another blinded, placebo-controlled trial reported significant differences in the Modified Fatigue Impact Scale (MFIS) scores between amantadine-treated patients and placebo-received ones [9]. Ondansetron, a 5-HT3 receptor antagonist has been tested for treatment of chronic nausea and vertigo in MS patients [10] and for treatment of chronic hepatitis C-associated and biliary cirrhosis-associated fatigue [11, 12]. In the current randomized clinical trial, we compared the effects of amantadine and ondansetron on MS-associated fatigue. The objectives of the current study were evaluation of the effects of these drugs in Iranian MS patients and comparison between these drugs by using the Persian version of FSS. These drugs were chosen based on the results of previous studies indicating the effectiveness of amantadine and ondansetron in ameliorating fatigue in MS and cirrhosis, respectively. Moreover, as ondansetron has been useful for management of chronic nausea and vertigo in MS patients, if its effects on fatigue were comparable with commonly used anti-fatigue drugs in MS such as amantadine, it could be used as a treatment for MS patients who suffer from these three symptoms. The dose and the time of administration of amantadine (100 mg twice a day for 4 weeks) were selected based on the results of previous clinical trials in MS patients [7]. For ondansetron, the dose and time of administration were similar to the results a clinical trial in chronic hepatitis C patients [13].



The current clinical trial was conducted on patients referred to Imam Clinic and Sina Hospital, Hamadan, Iran during November 2018–March 2019. The severity of fatigue was scored based on the Persian version of FSS. The validity and reliability of Persian version of this scoring system had been approved previously [14]. Inclusion criteria for MS patients were age between 18 and 65 years, fatigue complaint, the ability to walk without assistance of at least 100 m, FSS score ≥ 28. Exclusion criteria were systemic diseases such as cardiovascular diseases, infection, thyroid disease, or vasculitis, taking other drugs that affect fatigue symptom (beta blockers, antidepressants, sedatives, modafinil, Ritalin or pemoline) in the prior 6 months period, risk factors for long QT, electrolyte imbalance, close-angle glaucoma or pregnancy.

Consent form was filled out by all the study participants and the study protocol was approved by the local Ethical committee of Hamadan University of Medical Sciences (IR.UMSHA.REC.1397.500). The clinical trial registry number was IRCT20120215009014N250.

Study design

This was a randomized crossover clinical trial. Non-probability sampling method (convenience sampling) was used. Sixty-one MS patients were randomly assigned to two groups receiving ondansetron (4 mg twice a day) or amantadine (100 mg twice a day) for 4 weeks. Fatigue was assessed using FSS. After a two-week discontinuing of drugs, patients received the other drug for another 4 week period. Any side effect of drugs was assessed to conduct appropriate interventions if needed.

Measured outcomes

Fatigue score before and 4 weeks after treatment.

Statistical methods

Data were analyzed using SPSS v. 16 (IBM Corp, Chicago, IL, USA). P values less than 0.05 were considered as significant. Quantitative variables were described using mean and standard deviation (SD), whereas categorical variables were expressed as ratios or percentages. Independent and paired t tests were used for comparison of FSS between two groups or within each group before and after intervention, respectively. Fisher exact test was used for comparisons when ranking the severity of fatigue (mild, moderate, and severe).


Eight patients (5 from ondansetron group and 3 from amantadine group) were excluded from the study due to non-compliance with drug therapy. The mean age (± SD) of study participants was 54.00 (± 7.88). Female/male ratio was 45/8. Thirty-nine (73.6%) of patients had fatigue as the only symptom. The frequencies of other symptoms in study participants which needed medical interventions are shown in Table 1.

Table 1 The frequencies of other symptoms in study participants which needed medical interventions

Statistical analyses using student t test showed no significant difference in FSS between study groups either before treatment or after treatment (Table 2).

Table 2 Fatigue severity scores (mean ± SD) in amantadine and ondansetron groups before and after treatment

However, FSS was significantly decreased in both groups after treatment (P < 0.001).

Severity of fatigue was also self-assessed as mild, moderate, or severe. Fisher exact test showed significant decrease in fatigue severity in both amantadine-treated group (P = 0.002) and ondansetron-treated group (P < 0.001) (Tables 3, 4).

Table 3 Fatigue severity base on patients’ self report after and before treatment with amantadine
Table 4 Fatigue severity base on patients’ self report after and before treatment with ondansetron

While fatigue severity was not different between study groups before treatment (P = 0.21), there was a significant difference between two groups after treatments (P = 0.026) in a way that amantadine decreased severity of fatigue more than ondansetron.

We also assessed the effects of treatments in reduction of FSS to less than 28. Based on the statistical analyses, no significant difference was detected between two groups after treatments in this regard (P = 0.22) (Table 5).

Table 5 The effects of treatments on fatigue cure as described by FSS < 28

No side effect or complication was reported following treatment with either drug.


Fatigue is the most frequently described symptom among MS patients and one of the most incapacitating symptoms in these patients [1]. The majority of MS patients complain from fatigue in a time point during MS course [15]. Fatigue is an independent factor associated with compromised quality of life in MS patients, after adjustment of the effects of physical disability. Consequently, anti-fatigue therapies are expected to increase quality of life in these patients [4]. Different mechanisms are involved in the pathogenesis of MS-related fatigue among them are secretion of proinflammatory cytokines, endocrine disturbances, axonal damage, and changed patterns of cerebral activation [1]. Among several pharmacological strategies to ameliorate fatigue are amantadine and ondansetron. Being primarily administered for treatment of Influenza infection and Parkinson’s disease, amantadine is the most broadly assessed drug for MS-related fatigue [1]. Numerous placebo-controlled trials reported beneficial effects of amantadine in reduction of fatigue based on subjective assessments [16]. However, based on the small sample sizes of the mentioned studies and possible biases in their designs, there is no consensus on formal prescribing of this drug in MS-associated fatigue [17]. Although data regarding the role of ondansetron in reduction of fatigue is less than amantadine, ondansetron has been successfully prescribed in patients with primary biliary cirrhosis [12] and chronic hepatitis C [13]. In the current crossover clinical trial, we compared the effects of these two drugs in reduction of fatigue in a population of Iranian MS patients. Notably, both drugs could reduce fatigue severity as reported by FSS as well as patients’ self-report. A former meta-analysis has assessed data of a parallel arms study and 4 crossover clinical trials about the effects of amantadine in MS-associated fatigue. All of them had demonstrated trivial and inconsistent amelioration of fatigue. However, the clinical significance of these reports and the influence on patient’s quality of life had not been assessed [18]. The results of current clinical trial verify the effects amantadine in improvement of this symptom and add to the sample size of the previous meta-analyses. However, the reduction in fatigue score in the current trial was not trivial. Certainly, future meta-analyses are required to provide recommendations for drug prescription.

Administration of 4 mg ondansetron twice a day in patients with chronic hepatitis C has remarkably decreased the fatigue score with more than 30% while placebo did not [13]. Such data is consistent with the results of the current study.

Although there was no significant difference in the effects of amantadine and ondansetron based on FSS, amantadine was more effective in reduction of fatigue severity according to the patients’ self-report. A previous meta-analysis reported the occurrence of amantadine-related side effects to be varied from 10 to 57% [18]. In the current study, none of drugs caused side effects or complications that needed medical intervention. Considering the negative impact of fatigue on quality of life of MS patients, our data indicates an improvement in this index in the assessed population of MS patients.


Consequently, the current study demonstrates the comparable effects of amantadine and ondansetron on reduction of MS-associated fatigue as described by FSS. However, further studies in larger sample sizes are needed to verify our results. Moreover, although evidences suggest that fatigue is associated with serotoninergic pathways [13], further studies are needed to unravel the mechanisms by which these drugs affect patients’ fatigability.



multiple sclerosis


Fatigue Severity Scale


Modified Fatigue Impact Scale


standard deviation


  1. 1.

    Braley TJ, Chervin RD (2010) Fatigue in multiple sclerosis: mechanisms, evaluation, and treatment. Sleep 33(8):1061–1067

    Article  Google Scholar 

  2. 2.

    Nagaraj K, Taly AB, Gupta A, Prasad C, Christopher R (2013) Prevalence of fatigue in patients with multiple sclerosis and its effect on the quality of life. J Neurosci Rural Pract 4(3):278–282 (Epub 2013/11/20)

    Article  Google Scholar 

  3. 3.

    Krupp LB, Alvarez LA, LaRocca NG, Scheinberg LC (1988) Fatigue in multiple sclerosis. Arch Neurol 45(4):435–437 (Epub 1988/04/01)

    CAS  Article  Google Scholar 

  4. 4.

    Janardhan V, Bakshi R (2002) Quality of life in patients with multiple sclerosis: the impact of fatigue and depression. J Neurol Sci 205(1):51–58 (Epub 2002/11/01)

    Article  Google Scholar 

  5. 5.

    Krupp LB, LaRocca NG, Muir-Nash J, Steinberg AD (1989) The Fatigue Severity Scale. Application to patients with multiple sclerosis and systemic lupus erythematosus. Arch Neurol 46(10):1121–1123 (Epub 1989/10/01)

    CAS  Article  Google Scholar 

  6. 6.

    Miller P, Soundy A (2017) The pharmacological and non-pharmacological interventions for the management of fatigue related multiple sclerosis. J Neurol Sci 381:41–54 (Epub 2017/10/11)

    CAS  Article  Google Scholar 

  7. 7.

    Generali JA, Cada DJ (2014) Amantadine: multiple sclerosis-related fatigue. Hosp Pharm 49(8):710–712

    CAS  Article  Google Scholar 

  8. 8.

    Shaygannejad V, Janghorbani M, Ashtari F, Zakeri H (2012) Comparison of the effect of aspirin and amantadine for the treatment of fatigue in multiple sclerosis: a randomized, blinded, crossover study. Neurol Res 34(9):854–858 (Epub 2012/09/18)

    CAS  Article  Google Scholar 

  9. 9.

    Ledinek AH, Sajko MC, Rot U (2013) Evaluating the effects of amantadine, modafinil and acetyl-L-carnitine on fatigue in multiple sclerosis—result of a pilot randomized, blind study. Clin Neurol Neurosurg 115(Suppl 1):S86–S89 (Epub 2014/01/01)

    Article  Google Scholar 

  10. 10.

    Macleod AD (2000) Ondansetron in multiple sclerosis. J Pain Symptom Manag 20(5):388–391

    CAS  Article  Google Scholar 

  11. 11.

    Dimitrov DH (2009) Effect of Ondansetron, a 5-HT(3) receptor antagonist, on fatigue in 2 veterans with hepatitis C. Primary Care Companion J Clin Psychiatry 11(6):366–367 (Epub 2010/01/26)

    Article  Google Scholar 

  12. 12.

    Theal JJ, Toosi MN, Girlan L, Heslegrave RJ, Huet PM, Burak KW et al (2005) A randomized, controlled crossover trial of ondansetron in patients with primary biliary cirrhosis and fatigue. Hepatology 41(6):1305–1312 (Epub 2005/05/26)

    CAS  Article  Google Scholar 

  13. 13.

    Piche T, Vanbiervliet G, Cherikh F, Antoun Z, Huet PM, Gelsi E et al (2005) Effect of ondansetron, a 5-HT3 receptor antagonist, on fatigue in chronic hepatitis C: a randomised, double blind, placebo controlled study. Gut 54(8):1169–1173 (Epub 2005/07/13)

    CAS  Article  Google Scholar 

  14. 14.

    A’zimian M, Fallah-Pour M, Karimlou M (2013) Evaluation of reliability and validity of the Persian version of Fatigue Severity Scale (FSS) among persons with multiple sclerosis. Archiv Rehabil 13(4):84–91

    Google Scholar 

  15. 15.

    Krupp L (2006) Fatigue is intrinsic to multiple sclerosis (MS) and is the most commonly reported symptom of the disease. Multi Scler 12(4):367–368 (Epub 2006/08/12)

    Article  Google Scholar 

  16. 16.

    Cohen RA, Fisher M (1989) Amantadine treatment of fatigue associated with multiple sclerosis. Arch Neurol 46(6):676–680 (Epub 1989/06/01)

    CAS  Article  Google Scholar 

  17. 17.

    Taus C, Giuliani G, Pucci E, D’Amico R, Solari A (2003) Amantadine for fatigue in multiple sclerosis. Cochrane Database Syst Rev 2:CD002818 (Epub 2003/06/14)

    Google Scholar 

  18. 18.

    Pucci E, Branas P, D’Amico R, Giuliani G, Solari A, Taus C (2007) Amantadine for fatigue in multiple sclerosis. Cochrane Database Syst Rev 24(1):CD002818 (Epub 2007/01/27)

    Google Scholar 

Download references


The current study was supported by a grant from Hamadan University of Medical Sciences.


Not applicable.

Author information




MT and SGF wrote the manuscript. MK Supervised the study. AK analyzed the data. All authors read and approved the final manuscript.

Corresponding authors

Correspondence to Mohammad Taheri or Soudeh Ghafouri-Fard.

Ethics declarations

Availability of data and materials

The analysed data sets generated during the study are available from the corresponding author on reasonable request.

Ethics approval and consent to participate

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Consent of publication

Not applicable.

Competing interests

The authors declare they have no competing interests.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Khazaei, M., Karevan, A., Taheri, M. et al. Comparison of the effects of amantadine and ondansetron in treatment of fatigue in patients with multiple sclerosis. Clin Trans Med 8, 20 (2019).

Download citation


  • Multiple sclerosis
  • Fatigue amantadine
  • Ondansetron
  • Clinical trial