Onstrate pendular nystagmus as a new adverse impact of venlafaxine which has not previously been reported, and speculate that the aetiology may possibly reflect an incomplete form of the serotonin syndrome.OUTCOME AND FOLLOW-UPThe patient managed to sleep and, by the subsequent day, there was comprehensive resolution of nystagmus and brisk reflexes. She was noticed by the psychiatric group and discharged.DISCUSSIONSerotonin, also referred to as 5-hydroxytryptamine, functions within the CNS as a neurotransmitter. The serotonin syndrome describes the clinical manifestations of an excess of serotonin at central nerve synapses. The typical cause is drugs which boost synaptic serotonin, normally selective serotonin reuptake inhibitors (eg fluoxetine, paroxetine and citalopram) and SNRIs (eg venlafaxine and duloxetine). The clinical spectrum is broad, plus a number of diagnostic criteria happen to be developed.1 two In its full kind, the syndrome comprises a triad of neuromuscular excitability (tremor, rigidity, clonus and hyper-reflexia), autonomic disturbance (fever, shivering, sweating, tachycardia and mydriasis) and altered mental state (agitation and hypervigilance). Pendular nystagmus is definitely an involuntary oscillation in the eyes that happens with a sinusoidal waveform, as opposed to jerk nystagmus which displays a quickly and slow phase.7-(Benzyloxy)-4-chloroquinoline Purity Several causes happen to be described,3 and an association of binocular horizontal pendular nystagmus with serotonin toxicity is well recognised2 four; though in a lot of the literature, the abnormality is described as `ocular clonus’, in parity with limb clonus. To our expertise, isolated pendular nystagmus as a sign of serotonin toxicity has never ever been described, nor has pendular nystagmus as a consequence of venlafaxine overdose. We suspect that our case represents an incomplete kind (`forme fruste’) with the serotonin syndrome. The absence of other clinical capabilities of serotonin toxicity and also the typical investigations preluded a diagnosis in the total serotonin syndrome, as well as the case would not have met either the Sternbach or Hunter criteria.173252-76-1 Purity 1 2 Recognition of such incomplete types is very important, as theCASE PRESENTATIONA 54-year-old lady ingested three g of venlafaxine in a modified-release preparation (40 tablets of 75 mg).PMID:25105126 She presented towards the emergency department 4 h immediately after ingestion, reporting blurred vision, dry mouth, nausea and vomiting. She denied co-ingestion of alcohol or any other substances, and was not on any normal medication. On examination, temperature was 36.4 , pulse 101 bpm, blood pressure 142/89 mm Hg and oxygen saturation 98 on area air. She was calm, alert and oriented. She was not sweaty, shivery or tremulous. Muscle tone was standard. All reflexes have been markedly brisk but there was no limb clonus, and plantars had been downgoing. Examination of eye movements demonstrated binocular horizontal pendular nystagmus together with the eyes inside the principal position (see video 1). Amplitude of nystagmus decreased with lateral gaze and was increased by central visual fixation. There was no ophthalmoplegia, and smooth pursuit and saccadic eye movements were preserved.To cite: Varatharaj A, Moran J. BMJ Case Rep Published on-line: [please incorporate Day Month Year] doi:ten.1136/bcr-INVESTIGATIONSAn ECG showed sinus rhythm with proper axis deviation and suitable bundle branch block, using a corrected QT interval of 415 ms. Routine blood tests have been within standard limits, using a creatine kinase level of 132 units/L (range 0?45). ParacetamolVaratharaj A, et al. BMJ Case R.