Evaluation of metronidazole toxicity: a prospective study

Area of Science:

• Pharmacology
• Neurology
• Toxicology

Background:

• Metronidazole is a common antimicrobial and antiprotozoal drug.
• Prolonged metronidazole use is sometimes necessary for certain infections.
• Metronidazole-induced peripheral neuropathy is a known but rarely studied toxicity.

Purpose of the Study:

• To prospectively evaluate the toxic profile of long-term metronidazole therapy.
• To investigate the incidence and nature of metronidazole-induced neurotoxicity.
• To assess neurological effects in patients undergoing extended metronidazole treatment.

Main Methods:

• A prospective study involving 17 patients (20-50 years) receiving oral metronidazole (400 mg t.i.d.).
• Treatment duration ranged from 2-4 weeks, with total doses between 16.8-39.6 g.
• Neurological examinations included deep tendon reflexes and nerve conduction studies (sural and posterior tibial nerves).

Main Results:

• Common side effects included metallic taste, headache, and dry mouth.
• More severe neurological effects observed: reduced ankle jerks (4 patients), impaired vibration sense (2 patients).
• Nerve conduction studies showed significant alterations in distal latency and velocity (p < 0.01), indicating motor-sensory neurotoxicity.

Conclusions:

• Long-term metronidazole therapy is associated with significant motor-sensory neurotoxicity, particularly affecting the lower limbs.
• Neurological symptoms appear proportional to the duration of metronidazole treatment.
• This study highlights the importance of monitoring for neurological side effects during prolonged metronidazole use.