Retrospective Study
Copyright ©The Author(s) 2021.
World J Psychiatr. Apr 19, 2021; 11(4): 124-132
Published online Apr 19, 2021. doi: 10.5498/wjp.v11.i4.124
Table 1 Details of patients with chronic serotonin syndrome
Details of the clinical characteristics
Serotonergic agent and its details
Treatment and follow up
Presenting complaint
Other symptoms and signs
Duration of illness
49, FGeneralized body pain, fatigue, restlessness, tremorsDizziness, insomnia, tachycardia, rigidity, clonus6-8 wkValproate for 2 yr for epilepsy, sertraline added 3 mo back for depressionCK- 566 U/LDiscontinued sertraline. Cyproheptadine (4 mg bid) was started. Marked improvement in 2 d. Complete response within 5 d. No recurrence in follow-up
57, MIrritability, disturbed sleep, slowness in gait, disturbed bowelTremors, sexual dysfunctions, tachycardia, rigidity, clonus3 moTramadol and amitriptyline for paraesthesia for 1 yrNormalDiscontinued drugs. Cyproheptadine (4 mg bid) was started. Response began within 48 h. Complete response within 7 d
32, FHeadache, generalized body pain, tremorsIntermittent diaphoresis, tachycardia, rigidity, clonus2 moValproate (500 mg bid) for 6 mo for epilepsyCK- 1283 U/LMarked improvement by cyproheptadine (4 mg tid). Valproate changed to levetiracetam. Follow- up was uneventful
46, FSlowness in work and gait, bladder dysfunctions, dizziness, tremorsDizziness, sexual dysfunctions, tachycardia, rigidity, clonus3 moAmitriptyline and citalopram for 1 yr for bipolar disorderNormalDiscontinued the offending drugs. Cyproheptadine (4 mg tid) for 3 wk. Response began in 48 h. Complete response within 10
58, MSlowness in gait, pain and stiffness in the limbs and neck, tremorsNystagmus, tachycardia, rigidity, clonus10-12 wkTramadol, and fluoxetine for 4 mo for carpal tunnel syndromeCK-879 U/LCyproheptadine (4 mg tid) for 2 wk. Response began in 2 d. Complete response within 5-7 d. No recurrence in follow-up
37, FTremors, irritability, fatigue, muscle pain, bowel disturbancesTachycardia, hypertension, hypertonia, clonus8-10 wkAmitriptyline and valproate for chronic migraine for 6 moNormalStarted cyproheptadine (4 mg bid). Complete response within 4-6 d. Cyproheptadine was continued as an anti-migraine drug
31, MGait problems, stiff legs, bowel disturbancesTremors, spasticity, clonus, diaphoresis9-10 wkParoxetine (40 mg/d) for 6 mo for depressionCK-1279 U/LDiscontinued paroxetine. Cyproheptadine (6 mg tid) for 3 wk
47, MInsomnia, dizziness, restlessness, bowel disturbance, episodic sweatingTremor tachycardia, rigidity, clonus, hyperreflexia3-4 moSertraline and valproate for mood disorder for 9 moCK-634 U/LDiscontinued both drugs. Cyproheptadine (4 mg bid) for 4 wk
42, FGeneralized body pain, stiff body, constipationTremors, nystagmus, rigidity, stiff neck, hyperreflexia8-10 wkTramadol and amitriptyline for 3 mo for pain after radius fractureCK-1134 U/LStarted cyproheptadine (4 mg tid). Marked response in 7 d. Cyproheptadine was continued for 6 wk
54, MDystonic tremor, incoordination, stiffness in legs, episodic sweatingTremors, nystagmus, rigidity, clonus, hyperreflexia6-8 wkAmitriptyline and tramadol for 3 mo for cervical spondylosisNormalStopped both drugs. Started cyproheptadine (4 mg tid). Complete response in 7 d. Cyproheptadine was continued for 6 wk
61, MTremors, stiffness, incoordination, sexual dysfunction, insomniaNystagmus, rigidity, clonus, hypertension4-5 moAddicted to tramadol for 2 yr for neuropathic painNormalMarked improvement with cyproheptadine (4 mg tid). The patient did not stop tramadol and he continued cyproheptadine
Table 2 Epidemiological profiles and clinical features of 14 patients with chronic serotonin syndrome
n (%)
Age in yr, mean ± SD44.1 ± 11.6
Sex, M:F9:5 (1.8:1)
Duration of illness in wk13.5 ± 5.8
Clinical characteristics
Tremor14 (100)
Hyperreflexia14 (100)
Clonus13 (93)
Spasticity-rigidity11 (79)
Tachycardia9 (64)
Generalized pain7 (50)
Insomnia7 (50)
Irritability-restlessness7 (50)
Stiffness 6 (43)
Diaphoresis6 (43)
Gait disturbances5 (36)
Bowel disturbances5 (36)
Dizziness 4 (29)
Sexual dysfunctions3 (21)
Nystagmus3 (21)
Hypertension 2 (14)
Incoordination2 (14)
Fatigue2 (14)
Fulfilments of SS criteria
Hunter criteria14 (100)
Sternbach’s criteria 11 (78)
Serotonergic agents implicated in 14 cases
Amitriptyline6 (43)
Tramadol5 (36)
Valproate5 (36)
Paroxetine 2 (14)
Sertraline2 (14)
Citalopram1 (7)
Fluoxetine1 (7)