NORTIZ TABLETS

Indications

• Urinary tract infections
• Prostatitis
• Gastrointestinal infections
• Traveler's diarrhea
• Bacterial conjunctivitis

Dosage

Children: Refer to BNF for Children for specific dosing information based on the condition being treated.

Adults: Refer to BNF for specific dosing information based on the condition being treated.

Mechanism of action

Norfloxacin works by inhibiting bacterial DNA gyrase and topoisomerase IV, enzymes essential for bacterial DNA replication, transcription, and repair. By interfering with these enzymes, norfloxacin disrupts DNA synthesis, ultimately leading to bacterial cell death.

Pharmacodynamics

Norfloxacin demonstrates concentration-dependent killing, meaning its efficacy increases with higher drug concentrations. Its spectrum of activity includes many strains of Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. The drug's safety profile is generally acceptable, but it may cause adverse effects like gastrointestinal disturbances, central nervous system effects, and potential tendon damage.

Pharmacokinetics

Norfloxacin has a bioavailability of approximately 30-40% when taken orally, with peak plasma concentrations occurring 1-2 hours post-administration. It is primarily excreted via the kidneys, with around 30-50% of the dose eliminated unchanged in the urine. The half-life of norfloxacin ranges from 3 to 6 hours, which may vary based on renal function. The drug can accumulate in patients with compromised renal function, necessitating dose adjustments.

Contra-indications

• Hypersensitivity to norfloxacin or any of its components
• History of tendon disorders related to fluoroquinolone use
• Pregnancy and lactation
• Concurrent use of tizanidine

Adverse effects

• Nausea
• Diarrhea
• Dizziness
• Headache
• Phototoxicity
• Tendon rupture
• QT interval prolongation
• Peripheral neuropathy
• CNS effects including confusion and seizures

Interactions

• Antacids containing magnesium, aluminum, or calcium may decrease the absorption of norfloxacin
• Nonsteroidal anti-inflammatory drugs (NSAIDs) may increase the risk of CNS stimulation
• Theophylline levels may be increased when taken with norfloxacin
• Corticosteroids may increase the risk of tendon rupture

Precautions

• Use with caution in patients with renal impairment
• Monitor for signs of tendon pain or inflammation
• Caution in patients with a history of seizures or CNS disorders
• Use with caution in patients with myasthenia gravis

Pregnancy

Norfloxacin is not recommended during pregnancy due to potential harm to the fetus.

Breast-feeding

Norfloxacin is not recommended during breastfeeding as it may be excreted in breast milk.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Tablets: 400 mg
• Oral solution: 100 mg/5 mL

Indications

• Intestinal amoebiasis
• Urogenital trichomoniasis
• Giardiasis

Dosage

Children: For children aged 1 month to 11 years, the dosage is 50–75 mg/kg once, with a maximum of 2 g per dose. For children aged 12 to 17 years, the dosage is 2 g for a single dose, which may be repeated once if necessary.

Adults: The usual adult dosage is 2 g taken orally as a single dose for urogenital trichomoniasis or giardiasis, and 1.5 g to 2 g once daily for 3 to 6 days for intestinal amoebiasis.

Mechanism of action

Tinidazole acts as a prodrug and antiprotozoal agent. Its nitro group is reduced in Trichomonas by a ferredoxin-mediated electron transport system, generating free nitro radicals that covalently bind to DNA, causing DNA damage and cell death. The exact mechanism of action against Giardia and Entamoeba species is not fully understood but is believed to be similar to that of Trichomonas.

Pharmacodynamics

Tinidazole demonstrates in vitro and clinical activity against Trichomonas vaginalis, Giardia duodenalis (also known as G. lamblia), and Entamoeba histolytica. It does not exhibit significant activity against most strains of vaginal lactobacilli, which are beneficial bacteria in the vaginal flora.

Pharmacokinetics

Tinidazole is well absorbed following oral administration, with peak plasma concentrations occurring within 0.5 to 3 hours. It is extensively distributed throughout body tissues and fluids. The drug undergoes hepatic metabolism and is eliminated primarily through the urine, with a half-life of approximately 12 to 14 hours. Clinical and laboratory monitoring is advised if treatment extends beyond 10 days.

Adverse effects

• Abdominal pain
• Decreased appetite
• Diarrhoea
• Headache
• Nausea
• Skin reactions
• Vertigo
• Vomiting

Precautions

• Clinical and laboratory monitoring is advised if treatment exceeds 10 days

Pregnancy

Manufacturer advises avoiding use in the first trimester.

Breast-feeding

Present in milk; the manufacturer advises avoiding breastfeeding during and for 3 days after stopping treatment.

Storage

Store below 25°C, protect from moisture.

Formulations

• Tinidazole 500 mg tablets
• Tinidazole oral suspension

Mechanism of action

Tinidazole is a prodrug and antiprotozoal agent. The nitro group of tinidazole is reduced in <i>Trichomonas</i> by a ferredoxin-mediated electron transport system. The free nitro radical generated as a result of this reduction is believed to be responsible for the antiprotozoal activity. It is suggested that the toxic free radicals covalently bind to DNA, causing DNA damage and leading to cell death. The mechanism by which tinidazole exhibits activity against <i>Giardia</i> and <i>Entamoeba</i> species is not known, though it is probably similar. The nitro group of tinidazole is reduced by cell extracts of Trichomonas. As a result of this reduction a free nitro radical is generated which may be responsible for the antiprotozoal activity. The mechanism by which tinidazole exhibits activity against Giardia and Entamoeba species is not known.

Pharmacodynamics

Tinidazole is a synthetic antiprotozoal agent. Tinidazole demonstrates activity both in vitro and in clinical infections against the following protozoa: <i>Trichomonas vaginalis</i>, <i>Giardia duodenalis</i> (also termed <i>G. lamblia</i>), and <i>Entamoeba histolytica</i>. Tinidazole does not appear to have activity against most strains of vaginal lactobacilli.