Abstract

Background and objective: Tramadol can inhibit serotonin and norepinephrine reuptake leading to stimulation of the central component of the hiccup reflex arc. We have found only two previous cases of tramadol-induced hiccups. Additionally, three pharmacovigilance studies have investigated the involvement of tramadol in cases who have developed hiccups as adverse effects. Herein, we have presented a case of a middle-aged male who has developed hiccups shortly after tramadol intake.

Case Presentation: A 35-year-old male complaining of chronic pain in the right knee was treated with tramadol. The individual developed hiccups within 10 hours of the first tramadol dose. The patient tried to stop the hiccups with non-pharmacological measures, such as stopping the air inside the lungs and drinking cold fluids. The patient appeared to concentrate on avoiding hiccups, which he could avoid for some time. However, then, the hiccups would come all at a unique time. The hiccups occurred at a frequency of one hiccup/5-10 seconds, interrupting the patient's nutrition and sleep pattern. Eventually, tramadol was suspected of inducing hiccups, and baclofen was started.

Conclusion: Tramadol as well as opioids should be considered as a cause of hiccups. We aim to improve awareness about the safety of such drugs among physicians and the proper management of associated risks.

Keywords: Tramadol, opioid, hiccups, adverse effects, serotonin, pain.