Introduction: Tapentadol is a centrally-acting synthetic analgesic which acts as a mu-opioid receptor agonist as well as a norepinephrine re-uptake inhibitor. It is use to treat cronic pain. Most prevalence adverse effects are gastrointestinal and nervous symptoms. Furthermore, it has objectified, with less frequency, psychiatric disturbances. Objetives: To analyse the relationship between a maniac episode and tapentadol. Methods: Forty-nine-year-old female, with personal history of dyslipidemia and lumbar herniated discs in L4-L5, L5-S1, in treatment with tapentadol 200 mg/day for 20 days and no past psychiatric history. She was admitted to the Psychiatry Department due to a maniac episode, with desinhibition, pressure and loud speech, euphoria, megalomaniac delusion and sleep disturbance for the last 10 days. Young Mania Rating Scale (YMRS) was 36 points. Olanzapina 15 mg/day was introduced and tapentadol was removed. Symptoms remitted quickly and 6 days later, at discharge, YMRS was 4 points. One year later, the patient continued to be asymptomatic. Results: Opioids can produce psychiatric disorders like hallucination, sleep disorders, depressed mood, disorientation, agitation, nervousness, restlessness, euphoric mood. Secondary mania to tapentadol mechanism is unknown, but having opiate cases described, it is possible to attribute this episode to tapentadol. Conclusions:-Secondary mania is associated with various medical conditions, including vitamin B12 deficiency, brain injury, HIV infection and drugs such as alcohol, caffeine, sympathomimetics, steroids, bupropion, isoniazid, clarithromycin and opioids.-Further research is required to determine if the maniac episode was only isolated by the tapentadol or it is the beginning of a bipolar disorder.