Uncontrolled penile erection and increased sexual desire with intravenous moxifloxacin.

Sir,

We report an adverse reaction of uncontrolled penile erection and increased sexual desire due to moxifloxacin. To the best of our knowledge, this adverse effect has not been reported in the literature.

A 31-year-old male patient presented to our clinic with complaints of high fever, headache, myalgia, arthralgia, and purulent postnasal drip. Past medical history was unremarkable. There was a family history of hypertension. The respiratory system including chest x-ray was normal. Acute sinusitis was diagnosed and patient was prescribedmoxifloxacin 400 mg/ day intravenously. The patient presented with complaints of increased sexualdesire and uncontrolled penile erection at 12 h after the treatment. His fever was normal after 48 h. Intravenous moxifloxacin was replaced by to oral dosageon the third day. Complaints of uncontrolled penile erection and increased sexual desire of the patient were improved at the end of the fifth day. Oral moxifloxacin was continued to the 10th day. No symptom was observed on follow-up of the patient.

Moxifloxacin is a quinolone antibiotic. Quinolones are well tolerated with safety profiles similar to those of other antimicrobial agents. Some adverse effects as tendinitis and CNS-related effects are more common with quinolones than other antimicrobial agents.[1]

Brown reported a 31-year-old patient with prostatitis and premature ejaculation. He emphasized a therapeutic effect of ciprofloxacin on premature ejaculation (prolongation of ejaculation from 1–2 to 4–6 min) which was reversible.[2]

CNS side effects after administration of quinolones have been reported at the rate of 1–2%. The most common symptoms involve dizziness, somnolence, and headache. The less commonly reported symptoms have involved agitation, confusion, delirium, abnormal vision, and organic psychosis.[3] Abnormal dreams, depersonalization, depression (potentially culminating in self-endangering behavior, and emotional lability have been reported at the rate of less than 0.1%.[4] Moxifloxacin is a quinolone with potential for side effects associated with CNS.[1] Klossek et al. reported that CNS events such as dizziness and vertigo after moxifloxacin are observed more than five times more often than trovafloxacin.[5]

The cerebral areas especially the limbic system and hypothalamus are responsible for sexual function. However, it has been thought that anterior hypothalamic region and medial preoptic nucleus manage sexual behavior in men. It is known that dopamine is the most important neurotransmitter in sexual desire, fantasy, and motivation. Testosterone is also responsible for sexual desire.[6] To the best of our knowledge, differing side effects between intravenous or oral forms of moxifloxacin have not been described yet. In this particular case, causality assessment using the Naranjo scale,[7] showed that intravenous moxifloxacin was probably the causal drug for this adverse event.

Intravenous and oral moxifloxacin may differ in type and severity of adverse effects. Although rare, moxifloxacin may cause CNS adverse events that are reversible. Patients receiving intravenous moxifloxacinshould be closely followed-up and observed for these adverse events.