Ciprofloxacin is an antibiotic (fluoroquinolone) used to treat several bacterial infections (skin, bone, intestine, prostate, among others). It is effective, but is associated with rare yet serious effects (tendons, nerves), so it should be used only on medical advice.
Also known as: Ciprobay
Markedly reduced Ciprofloxacin absorption. Divalent cations (aluminium, magnesium, calcium, iron) chelate the fluoroquinolone.
Ciprofloxacin forms insoluble chelates with di- and trivalent cations (aluminium, magnesium, calcium) present in antacids, reducing oral bioavailability by up to 90% and risking therapeutic failure in serious infections (e.g., febrile neutropenia, complicated urinary tract infections). The ciprofloxacin label recommends administering the antibiotic 2 hours before or 6 hours after antacids containing magnesium or aluminium; the same care applies to calcium, iron and zinc supplements and to sucralfate. In hospitalised patients, check the administration schedule of both.
Antacids + ciprofloxacin: cations (Al, Mg, Ca) chelate ciprofloxacin and reduce absorption by up to ~90%. Administer ciprofloxacin 2 hours before or 6 hours after antacids.
Chelation between the antibiotic and cations in the gastrointestinal lumen.
Watch antibiotic efficacy (fever, unresolved infection signs).
Persistent fever, worsening symptoms or a new infection focus.
Give the antacid 2 hours after (or 6 hours before) Ciprofloxacin.
DailyMed/FDA (NIH/NLM) — approved Antacids label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c72f0736-ee20-45b4-baf0-b80f1e3fa9cb ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Two QT-prolonging drugs combined — risk of ventricular arrhythmias, higher in at-risk patients.
Both the artemether+lumefantrine combination and ciprofloxacin can prolong the QT interval, and the combination adds up the risk of ventricular arrhythmias, including torsade de pointes. The risk is higher in patients with congenital long QT, hypokalaemia, bradycardia, cardiac disease or taking other QT-prolonging drugs. Whenever possible, avoid the combination; if unavoidable (malaria in a patient needing an antibiotic), monitor the ECG and electrolytes, correct hypokalaemia/hypomagnesaemia and use the shortest possible ciprofloxacin course.
Artemether+lumefantrine + ciprofloxacin: both prolong the QT interval. Avoid or monitor the ECG in at-risk patients.
Additive effect on cardiac repolarisation (potassium channel blockade).
ECG (QTc) and electrolytes if risk factors.
Palpitations, syncope.
Caution in at-risk patients; ECG if vulnerability factors or symptoms.
DailyMed/FDA (NIH/NLM) — approved Artemether + Lumefantrine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=7866ec19-dfac-47d4-a53f-511a12643cbf ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Additive QT prolongation — low-to-moderate risk, higher in at-risk patients.
Mefloquine, used for malaria prophylaxis and treatment, prolongs the QT interval and can cause arrhythmias; ciprofloxacin adds the fluoroquinolone class effect. The combination adds up the risk of torsade de pointes, especially in patients with long QT, hypokalaemia, bradycardia or taking other QT-prolonging drugs. Whenever possible, avoid the combination or choose an alternative antibiotic; if unavoidable, monitor the ECG and electrolytes and use the shortest treatment duration possible.
Ciprofloxacin + mefloquine: additive risk of QT prolongation. Avoid or monitor the ECG in at-risk patients.
Additive effect on cardiac repolarisation.
ECG if risk factors.
Palpitations, syncope.
Caution in at-risk patients; ECG if symptoms.
DailyMed/FDA (NIH/NLM) — approved Mefloquine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=09716a24-d7da-42b2-af29-c03a1b6670bd ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Additive QT prolongation between Bedaquiline and Ciprofloxacin.
Bedaquiline, used in multidrug-resistant tuberculosis, prolongs the QT interval in a dose-dependent manner, and ciprofloxacin adds the same fluoroquinolone class effect. The combination increases the risk of torsade de pointes, especially in patients with risk factors (long QT, hypokalaemia, renal impairment, other QT-prolonging drugs). The bedaquiline label advises against co-administration with QT-prolonging drugs. In practice, prefer an antibiotic without QT effect when possible; if ciprofloxacin is unavoidable, monitor the ECG at start and during treatment and correct electrolytes.
Bedaquiline + ciprofloxacin: additive risk of QT prolongation. Avoid; if unavoidable, monitor the ECG.
Additive effect on cardiac repolarisation.
ECG (QTc).
Palpitations, syncope.
Caution; ECG if risk factors.
DailyMed/FDA (NIH/NLM) — approved Bedaquiline label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1534c9ae-4948-4cf4-9f66-222a99db6d0e ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
The combination is generally safe with no relevant interaction; usual therapy can be maintained.
Folic acid and ciprofloxacin do not share pharmacokinetic or pharmacodynamic pathways that would justify a clinically relevant interaction. There is no evidence that ciprofloxacin alters folate levels or that folic acid interferes with the antibacterial activity of the fluoroquinolone. The combination is common in practice (for example, prophylaxis in immunocompromised patients) and can be maintained without adjustments, only respecting the usual schedules of each drug.
The combination is generally safe with no relevant interaction; usual therapy can be maintained.
No known interaction mechanism between folate and fluoroquinolones.
No specific additional monitoring.
No specific red flags.
No dose adjustment needed.
DailyMed (FDA) — approved Folic acid label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0baa10dd-6d1d-4946-8236-566451132da3 ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c527d138-e32c-418f-9573-a3d8a796279f — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Ciprofloxacin + zinc: chelation reduces fluoroquinolone absorption.
Zinc, a divalent cation, forms insoluble chelates with fluoroquinolones in the gastrointestinal tract, reducing the oral bioavailability of ciprofloxacin — with risk of therapeutic failure in infections such as urinary or respiratory tract infections. The ciprofloxacin label recommends giving the antibiotic 2 hours before or 6 hours after zinc, iron or calcium supplements and antacids. In patients taking zinc supplements (common in acute paediatric diarrhoea, wounds or deficiency), separate the doses and, if possible, give zinc with the meal furthest from the antibiotic.
Zinc + ciprofloxacin: chelation with reduced absorption. Separate by 2–6 h.
Zinc forms complexes with ciprofloxacin in the gut.
Clinical response to antibiotic therapy.
Therapy failure, unresolved infection.
Separate dosing by at least 2 hours.
DailyMed (FDA) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c527d138-e32c-418f-9573-a3d8a796279f ; approved Zinc (zinc sulfate) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=2bd646d2-2a2a-4376-8da0-c7f08b0511ac — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Ciprofloxacin + calcium: chelation reduces fluoroquinolone absorption.
Divalent and trivalent cations (calcium, magnesium, aluminium, iron, zinc) form insoluble chelates with fluoroquinolones in the gastrointestinal tract, reducing oral bioavailability and potentially compromising antibacterial treatment. The ciprofloxacin label recommends giving the antibiotic 2 hours before or 6 hours after magnesium- or aluminium-containing antacids and calcium, iron or zinc supplements. This precaution is especially relevant in patients taking calcium supplements during an antibiotic course (e.g., osteoporosis) — check the timing on the prescription and, if possible, give calcium with the meal furthest from the antibiotic dose.
Calcium + ciprofloxacin: chelation with reduced fluoroquinolone absorption. Separate administration by 2–6 h.
Calcium cations chelate ciprofloxacin in the gut, reducing its oral absorption.
Clinical response to antibiotic therapy.
Therapy failure, unresolved infection.
Separate calcium and ciprofloxacin dosing by at least 2 hours.
DailyMed (FDA) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c527d138-e32c-418f-9573-a3d8a796279f ; approved Calcium carbonate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=348d3dfa-6a52-4583-96e3-83c4bf2df45b — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Ciprofloxacin reduces theophylline clearance and may increase its toxicity.
Ciprofloxacin is an inhibitor of CYP1A2, the enzyme that metabolises theophylline, and can raise theophylline serum concentrations by about 40% (per the theophylline label) and precipitate toxicity (nausea, vomiting, tachycardia, tremor, seizures, arrhythmias). The theophylline label recommends monitoring serum levels and adjusting the dose when ciprofloxacin is started or stopped, and watching for signs of toxicity (the ciprofloxacin label reports serious and fatal reactions with the combination). The interaction is particularly relevant in COPD/asthma patients on chronic theophylline.
Ciprofloxacin + theophylline: ciprofloxacin inhibits CYP1A2 and can raise theophylline (~40%), with a risk of toxicity. Monitor levels.
Ciprofloxacin inhibits CYP1A2, raising theophylline concentrations.
Monitor signs of theophylline toxicity (nausea, tremor, tachycardia, seizures).
Seizures, serious arrhythmias.
Reduce the theophylline dose or monitor levels during ciprofloxacin treatment.
DailyMed (FDA) — approved Theophylline label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5e64036a-ee3e-42e7-9e59-881f88a4e298 ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c527d138-e32c-418f-9573-a3d8a796279f — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Additive QT prolongation; low-to-moderate risk, higher in patients with risk factors.
Chloroquine, an antimalarial and immunomodulator, prolongs the QT interval and can cause torsade de pointes; ciprofloxacin belongs to the fluoroquinolone class, also associated with QT prolongation. The combination adds up the risk, especially in patients with long QT, hypokalaemia, cardiac disease or taking other QT-prolonging drugs. Whenever possible, avoid the combination or choose an alternative antibiotic; if unavoidable, monitor the ECG and electrolytes and use the shortest treatment duration possible.
Ciprofloxacin + chloroquine: additive risk of QT prolongation. Avoid or monitor the ECG in at-risk patients.
Ciprofloxacin and Chloroquine both slightly prolong QT — additive effect on repolarisation.
ECG if risk factors or symptoms.
Palpitations, syncope.
Caution in at-risk patients (long QT, hypokalaemia, elderly); monitor if symptomatic.
DailyMed/FDA (NIH/NLM) — approved Chloroquine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=06c69e2b-211b-4746-9f3a-f86d36520570 ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Ciprofloxacin + magnesium: chelation reduces fluoroquinolone absorption.
Magnesium, a divalent cation, forms insoluble chelates with fluoroquinolones in the gastrointestinal tract, reducing the oral bioavailability of ciprofloxacin and the risk of therapeutic failure in serious infections. The ciprofloxacin label recommends giving the antibiotic 2 hours before or 6 hours after magnesium-containing antacids or supplements (including magnesium laxatives). In hospitalised patients receiving oral/enteral magnesium sulfate and ciprofloxacin, check the administration times of both to ensure antibacterial efficacy.
Magnesium + ciprofloxacin: chelation with reduced absorption. Separate by 2–6 h.
Magnesium cations chelate ciprofloxacin in the gut.
Clinical response to antibiotic therapy.
Therapy failure.
Separate oral dosing by at least 2 hours.
DailyMed (FDA) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c527d138-e32c-418f-9573-a3d8a796279f ; approved Magnesium sulfate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a5a9f565-639c-4b22-b9e5-718bac7cfcf3 — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Additive QT prolongation (Piperaquine + Ciprofloxacin) — risk of ventricular arrhythmias.
Piperaquine (component of the dihydroartemisinin+piperaquine combination used in malaria) significantly prolongs the QT interval, and ciprofloxacin adds the fluoroquinolone class effect. The combination increases the risk of torsade de pointes, especially in patients with long QT, hypokalaemia or taking other QT-prolonging drugs. The European EPAR for Eurartesim recommends caution with QT-prolonging drugs. If the combination is unavoidable, monitor the ECG and electrolytes and avoid other risk factors.
Ciprofloxacin + dihydroartemisinin+piperaquine: additive risk of QT prolongation. Avoid or monitor the ECG.
Additive effect on cardiac repolarisation.
ECG (QTc) and electrolytes.
Palpitations, syncope.
Caution in at-risk patients; ECG if symptoms.
EMA — EPAR Eurartesim (dihydroartemisinin + piperaquine): https://www.ema.europa.eu/en/medicines/human/EPAR/eurartesim ; DailyMed/FDA (NIH/NLM) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Ciprofloxacin may increase domperidone exposure and add QT-interval effects.
Domperidone, a prokinetic antiemetic, prolongs the QT interval and is associated with torsade de pointes, especially at high doses or with risk factors; ciprofloxacin belongs to the fluoroquinolone class with the same effect. The combination adds up the risk of ventricular arrhythmias, particularly in the elderly, patients with cardiac disease, hypokalaemia or taking other QT-prolonging drugs. Whenever possible, choose an antibiotic without QT effect or an alternative antiemetic; if unavoidable, monitor the ECG and electrolytes.
Ciprofloxacin + domperidone: additive risk of QT prolongation. Avoid in at-risk patients.
Ciprofloxacin partially inhibits CYP3A4 and both prolong the QT.
Monitor ECG in patients with risk factors (hypokalaemia, bradycardia, other QT drugs).
Ventricular arrhythmias, torsade de pointes (rare).
Use with caution; consider an alternative if QT risk factors are present.
DailyMed (FDA) — approved Domperidone label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=cdb0c9b9-388c-4a06-9fe9-bb4e52278a4e ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c527d138-e32c-418f-9573-a3d8a796279f — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Iron markedly reduces ciprofloxacin absorption through chelation.
Iron salts (ferrous, ferrous fumarate, etc.) release divalent cations that chelate ciprofloxacin in the gastrointestinal tract, reducing its oral bioavailability and potentially compromising antibacterial treatment. The ciprofloxacin label recommends administering the antibiotic 2 hours before or 6 hours after iron supplements (the same applies to antacids, calcium and zinc). This precaution is especially relevant in anaemic patients taking iron supplements during an antibiotic — check the schedules at prescription.
Ciprofloxacin + iron: iron cations chelate ciprofloxacin and reduce absorption. Administer 2 hours before or 6 hours after iron.
Fe2+/Fe3+ cations chelate the fluoroquinolone in the GI tract, reducing its bioavailability.
Monitor antibiotic efficacy (signs of persistent infection).
Therapeutic failure of ciprofloxacin; unresolved infection.
Give ciprofloxacin at least 2 hours before or 4 hours after iron.
DailyMed (FDA) — approved Iron label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=73d1f079-d8eb-44f4-b33d-05fb25b80c8f ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c527d138-e32c-418f-9573-a3d8a796279f — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Additive QT prolongation — risk of ventricular arrhythmias.
Quinine, used in severe malaria and cramps, prolongs the QT interval and can cause torsade de pointes, especially at high doses or with hypokalaemia; ciprofloxacin adds the fluoroquinolone class effect. The combination adds up the risk of ventricular arrhythmias, particularly in patients with long QT, cardiac disease or taking other QT-prolonging drugs. Whenever possible, avoid the combination or choose an alternative antibiotic; if unavoidable, monitor the ECG and electrolytes.
Ciprofloxacin + quinine: additive risk of QT prolongation. Avoid or monitor the ECG in at-risk patients.
Additive effect on cardiac repolarisation.
ECG (QTc) and electrolytes.
Palpitations, syncope.
Caution; ECG in at-risk patients.
DailyMed/FDA (NIH/NLM) — approved Quinine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1f32f05c-a215-40be-b951-e41a7b54a8a0 ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Sucralfate significantly reduces oral ciprofloxacin absorption when given at the same time.
Sucralfate, a gastric cytoprotective agent, forms chelates with fluoroquinolones in the gastrointestinal tract and reduces ciprofloxacin oral absorption in a clinically significant way (the sucralfate label documents reduced fluoroquinolone bioavailability; reductions of up to 90% are described for magnesium/aluminium antacids in the ciprofloxacin label). The ciprofloxacin label recommends administering the antibiotic 2 hours before or 6 hours after sucralfate (the same applies to antacids, iron, calcium and zinc). This precaution is important in ulcer patients taking sucralfate who need an antibiotic — check the schedules at prescription.
Ciprofloxacin + sucralfate: sucralfate markedly reduces ciprofloxacin absorption. Administer 2 hours before or 6 hours after.
Sucralfate chelates fluoroquinolones in the gastrointestinal tract.
Monitor the clinical response to antibiotic therapy.
Ciprofloxacin therapeutic failure.
Give ciprofloxacin 2 hours before or 6 hours after sucralfate.
DailyMed (FDA) — approved Sucralfate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e781cc0-24ec-4028-8262-dcef9873ea1f ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c527d138-e32c-418f-9573-a3d8a796279f — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Fluoroquinolone + methotrexate: possible increased methotrexate toxicity.
Methotrexate is eliminated mainly by renal tubular secretion, and penicillins and, above all, NSAIDs and some antibiotics such as ciprofloxacin can reduce that clearance (by competition in the renal tubule), raising methotrexate concentrations and the risk of myelosuppression, mucositis and nephrotoxicity. The risk is higher with high-dose methotrexate (chemotherapy) — where the combination should be avoided — and with low doses (rheumatoid arthritis) blood count, renal function and mucositis should be monitored, especially in the elderly.
Ciprofloxacin + methotrexate: the antibiotic can reduce renal methotrexate clearance and increase toxicity. Monitor closely.
Ciprofloxacin may reduce methotrexate renal clearance, raising its concentrations.
Full blood count and renal function during antibiotic therapy.
Marrow suppression: fever, oral ulcers, infections.
Use with caution and monitor full blood count and renal function.
DailyMed (FDA) — approved Methotrexate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=757d6cef-6696-7a1c-8074-01258aaa8bdd ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c527d138-e32c-418f-9573-a3d8a796279f — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Epinephrine + fluoroquinolone: theoretical risk of QTc prolongation.
Both epinephrine and ciprofloxacin can, in particular circumstances, contribute to QT interval prolongation, although the additive risk is essentially theoretical for this combination. In clinical practice the combination arises mainly in emergencies (anaphylaxis in a patient taking ciprofloxacin) or in severe infection with haemodynamic instability. The combination does not need to be avoided, but in patients with risk factors (congenital long QT, hypokalaemia, bradycardia, other QT-prolonging drugs) it is prudent to monitor the ECG and correct electrolytes.
Epinephrine + fluoroquinolone: theoretical risk of QTc prolongation. Monitor the ECG in at-risk patients.
Both may prolong the QTc interval in susceptible patients.
ECG in at-risk patients.
Palpitations, syncope.
Use with caution in patients with QTc risk factors.
DailyMed (FDA) — approved Epinephrine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5726eeca-db88-ba8e-e063-6294a90a927d ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c527d138-e32c-418f-9573-a3d8a796279f — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Ciprofloxacin can lower blood sugar too much in patients taking glimepiride. Monitor blood glucose carefully during the antibiotic.
Fluoroquinolones, including ciprofloxacin, alter glycaemic control through mechanisms that are not fully understood (blockade of ATP-dependent potassium channels in beta cells and altered insulin secretion). Documented cases of refractory hypoglycaemia with glyburide and ciprofloxacin exist, and the gliclazide SmPC (EMC-UK) recommends careful blood glucose monitoring in all patients on sulfonylureas and fluoroquinolones, with special attention to the elderly.
Fluoroquinolones can cause dysglycaemia (hypo- or hyperglycaemia) in diabetic patients, especially the elderly; with sulfonylureas there is a documented risk of severe, prolonged hypoglycaemia. Monitor blood glucose during the antibiotic.
Altered insulin secretion by fluoroquinolones, with additive risk with sulfonylureas.
Daily capillary glucose during the antibiotic.
Severe or prolonged hypoglycaemia; confusion, sweating, coma — seek immediate medical care.
Reinforce self-monitoring of blood glucose during the antibiotic; educate the patient on the signs of hypo- and hyperglycaemia.
PubMed — https://pubmed.ncbi.nlm.nih.gov/10918110/ and https://pubmed.ncbi.nlm.nih.gov/15362597/ ; EMC-UK (MHRA) — approved Glimepiride SmPC: https://www.medicines.org.uk/emc/product/10742/smpc ; DailyMed/FDA (NIH/NLM) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Ciprofloxacin can alter blood sugar in patients taking gliclazide, especially the elderly. Monitor blood glucose during the antibiotic.
The gliclazide SmPC (EMC-UK) explicitly mentions blood glucose disturbances, including hypo- and hyperglycaemia, in diabetic patients treated with fluoroquinolones, especially the elderly, recommending careful blood glucose monitoring in all patients on the combination. The mechanism involves fluoroquinolone-induced changes in insulin secretion.
The gliclazide SmPC (EMC-UK) recommends careful blood glucose monitoring with fluoroquinolones (dysglycaemia, especially in the elderly). Watch for hypo- and hyperglycaemia during and after the antibiotic.
Fluoroquinolone-induced changes in insulin secretion.
Capillary glucose; symptoms of hypo/hyperglycaemia.
Confusion, sweating, polyuria, intense thirst, coma — medical attention.
Monitor blood glucose daily during the antibiotic; instruct the patient on the signs of dysglycaemia.
EMC-UK (MHRA) — approved Gliclazide SmPC: https://www.medicines.org.uk/emc/product/1321/smpc ; DailyMed/FDA (NIH/NLM) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Ciprofloxacin can cause severe hypoglycaemia in patients taking glyburide. Monitor blood glucose carefully during the antibiotic.
Case reports document severe, prolonged (correction-refractory) hypoglycaemia in diabetic patients on glyburide who started ciprofloxacin, including elevated serum glyburide levels. Fluoroquinolones interfere with insulin secretion; with sulfonylureas, the dysglycaemia risk is well documented. Close blood glucose monitoring is recommended during and after the antibiotic, especially in the elderly and in patients with renal impairment.
Documented cases of refractory hypoglycaemia with glyburide + ciprofloxacin. Monitor blood glucose during the antibiotic and treat any hypoglycaemia promptly.
Altered insulin secretion by fluoroquinolones, with additive risk with sulfonylureas.
Capillary glucose during the antibiotic.
Severe or prolonged hypoglycaemia — sweating, confusion, coma.
Reinforce self-monitoring of blood glucose; treat any hypoglycaemia immediately and reassess the sulfonylurea dose.
PubMed — https://pubmed.ncbi.nlm.nih.gov/10918110/ and https://pubmed.ncbi.nlm.nih.gov/15362597/ ; DailyMed/FDA (NIH/NLM) — approved Glyburide label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=524eec41-37ee-419a-b7a1-d23e888ae6ab ; approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Ciprofloxacin may potentiate the anticoagulant effect of Warfarin, raising the INR and the bleeding risk.
Ciprofloxacin increases the effect of warfarin through three pathways: inhibition of CYP1A2 and CYP3A4 (enzymes that metabolise warfarin), reduction of the gut flora producing vitamin K and, potentially, displacement of protein binding. There are reports of marked INR elevations and severe, sometimes fatal, bleeding, so the warfarin label recommends INR monitoring when a fluoroquinolone is started or stopped. The interaction is more pronounced in the elderly and in patients with multiple comorbidities. Monitor the INR frequently during and after the antibiotic course and adjust the dose.
Ciprofloxacin inhibits CYP1A2/CYP3A4 and reduces gut flora, potentially raising the INR markedly. Monitor the INR during and after the antibiotic.
Ciprofloxacin inhibits CYP1A2 and, to a lesser extent, CYP3A4, reducing Warfarin metabolism; altered vitamin K-producing gut flora also contributes to the enhanced anticoagulant effect.
Monitor the INR more frequently and watch for bleeding signs.
An elevated INR, bleeding or spontaneous bruising require immediate evaluation.
Monitor the INR and adjust the warfarin dose during the combination; reinforce bleeding surveillance.
DailyMed/FDA (NIH/NLM) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=57e5832f-9168-1f24-e063-6294a90aaae6 ; approved Warfarin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=541c9a70-adaf-4ef3-94ba-ad4e70dfa057 — with additional reference: Prontuário Terapêutico do INFARMED, INFARMED (11th ed., 2012)
Ciprofloxacin inhibits CYP1A2 and reduces caffeine clearance, potentiating its effects (insomnia, nervousness, tachycardia).
Limit caffeine intake during treatment.
DailyMed/FDA (NIH/NLM) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Calcium in dairy chelates ciprofloxacin in the GI lumen and markedly reduces its absorption.
Do not take with milk, yoghurt or dairy; separate dosing 2 hours before or 6 hours after dairy.
DailyMed/FDA (NIH/NLM) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Ciprofloxacin prolongs the QT interval and increases the risk of torsades de pointes in at-risk patients.
Avoid in QT prolongation or uncorrected hypokalaemia; monitor ECG and electrolytes.
DailyMed/FDA (NIH/NLM) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Fluoroquinolones can lower the seizure threshold and precipitate seizures in predisposed patients.
Use with caution in patients with epilepsy or a history of seizures.
DailyMed/FDA (NIH/NLM) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Fluoroquinolones cause arthropathy in young animals; human data are limited, but use in pregnancy is generally avoided.
Avoid in pregnancy unless no safe alternative exists.
Excreted into breast milk; avoid while breastfeeding.
No specific additional contraception.
DailyMed/FDA (NIH/NLM) — approved Ciprofloxacin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14c3bc33-201d-492e-9aee-a4d84c813a3d
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Broad-spectrum bactericidal fluoroquinolone, active against Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa. After an oral dose, peak serum concentrations are reached in 1 to 2 hours and tissue concentrations often exceed serum levels.
The bactericidal action results from inhibition of topoisomerase II (DNA gyrase) and topoisomerase IV, enzymes essential for bacterial DNA replication, transcription, repair and recombination.
Absolute oral bioavailability is about 70%, with no substantial first-pass loss. Peak serum levels occur 1 to 2 hours after dosing; food delays the peak to about 2 hours without substantially affecting absorption. Serum protein binding is 20 to 40%. Milk, yoghurt, calcium-fortified juices and antacids reduce absorption.
Four metabolites have been identified in urine, together accounting for about 15% of an oral dose. Ciprofloxacin is an inhibitor of CYP1A2 and may increase the concentrations of drugs metabolised by this isoenzyme. About 40 to 50% of an oral dose is excreted unchanged in urine and 20 to 35% in faeces.
The serum elimination half-life in patients with normal renal function is approximately 4 hours (5 hours in children).
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
