Gyrablock (Norfloxacin)

Gyrablock is prescribed for the treatment of susceptible bacterial infections when an oral fluoroquinolone is appropriate.

• Uncomplicated urinary tract infections caused by susceptible Gram‑negative organisms.
• Acute bacterial gastroenteritis, including travel‑related diarrhoea, when norfloxacin‑sensitive pathogens are identified.
• Lower respiratory tract infections such as acute exacerbations of chronic bronchitis caused by susceptible bacteria.
• Skin and soft‑tissue infections, including cellulitis and wound infections, due to norfloxacin‑sensitive strains.
• Certain sexually transmitted infections, for example uncomplicated gonorrhoea, when susceptibility testing supports use.

Like other fluoroquinolones, Gyrablock may cause a range of adverse effects that vary in frequency and severity. These effects are related to the drug’s impact on bacterial DNA processes and may affect host tissues. Common side effects are usually mild and resolve after discontinuation, while serious reactions require immediate medical attention.

Common

• Nausea, vomiting or abdominal discomfort.
• Diarrhoea, which may be mild to moderate.
• Headache or dizziness.
• Skin rash or pruritus.

Serious

• Tendon inflammation or rupture, especially of the Achilles tendon.
• Peripheral neuropathy presenting as tingling, numbness or weakness.
• Severe allergic reactions such as anaphylaxis or Stevens‑Johnson syndrome.

Patients should report any signs of tendon pain, neuropathy, or severe skin reactions promptly.

Gyrablock should be used with caution in specific patient groups and clinical situations to minimise the risk of adverse outcomes.

• Avoid use in patients with a known hypersensitivity to norfloxacin or other fluoroquinolones.
• Use cautiously in individuals with a history of tendon disorders, especially if they are elderly or on corticosteroids.
• Assess renal function before prescribing, as dose adjustment may be required in renal impairment.
• Consider alternative therapy for pregnant or breastfeeding women, because safety data are limited.
• Monitor for signs of QT‑interval prolongation in patients with cardiac risk factors or those taking other QT‑prolonging drugs.
• Use with caution in patients with a history of seizures or other central nervous system disorders.

Gyrablock can interact with several medicines, altering its effectiveness or increasing the likelihood of side effects.

Avoid

• Antacids containing magnesium or aluminum, as well as iron supplements, which can markedly reduce norfloxacin absorption.
• Warfarin, because concomitant use may enhance anticoagulant effect and increase bleeding risk.
• Non‑steroidal anti‑inflammatory drugs (NSAIDs) that may raise the risk of central nervous system stimulation and seizures.

Use with caution

• Diabetic agents such as insulin or oral hypoglycemics, since fluoroquinolones can affect blood glucose control.
• Medications that prolong the QT interval (e.g., certain antiarrhythmics, macrolide antibiotics), requiring cardiac monitoring.
• Corticosteroids, especially in older patients, due to an increased risk of tendon rupture.