Gastric mucosal cytoprotectant (anti-ulcer)
Sucralfate is a medicine that forms a protective film over a stomach or duodenal ulcer, helping it heal. It is taken orally, usually 4 times a day, on an empty stomach (1 hour before meals and at bedtime). As it acts locally, it is poorly absorbed.
Also known as: Antepsin, Carafate, sucralfate
Antacids may reduce the protective effect of sucralfate when taken together.
Sucralfate is a cytoprotective agent that forms an adhesive barrier over the ulcer, but its polymerisation and activation depend on an acidic gastric medium. Antacids, by neutralising the acid, reduce the formation of that barrier and decrease sucralfate efficacy; additionally, sucralfate can reduce the absorption of co-administered drugs. The sucralfate label recommends not administering antacids within 30 minutes before or after sucralfate. In practice, instruct the patient to space the doses consistently (for example, sucralfate 1 hour before meals and the antacid at a separate time).
Antacids + sucralfate: antacids reduce sucralfate efficacy (pH-dependent activation). Do not administer within 30 minutes before or after sucralfate.
Antacids change gastric pH and may interfere with sucralfate polymerisation.
Monitor symptomatic response (epigastric pain, heartburn).
Recurrence of ulcer symptoms.
Separate sucralfate and antacid administration (30–60 minutes).
DailyMed (FDA) — approved Sucralfate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e781cc0-24ec-4028-8262-dcef9873ea1f ; approved Antacids label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5e346dc0-69ce-4cc5-bb5d-bfa833e11c1f — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Sucralfate + calcium: sucralfate binds calcium, reducing its absorption.
Sucralfate, a polymer of sulfated sucrose with aluminium hydroxide, forms an adherent layer over the gastric mucosa and binds various drugs and cations in the gastrointestinal tract, reducing their absorption. Concomitant calcium supplements decrease calcium bioavailability. Administration should be separated by at least 2 hours (ideally sucralfate 1 hour before meals and calcium at another time), also spacing other oral medicines, since sucralfate interferes with many of them.
Sucralfate + calcium: sucralfate binds calcium and reduces its absorption. Separate by 2 h.
Sucralfate forms a film that binds cations (including calcium) in the stomach.
Effectiveness of calcium supplementation.
No acute symptoms; risk of calcium deficiency with long-term use.
Separate dosing by at least 2 hours.
DailyMed (FDA) — approved Sucralfate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e781cc0-24ec-4028-8262-dcef9873ea1f ; 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)
Sucralfate + zinc: sucralfate binds zinc, reducing its absorption.
Sucralfate binds cations and various drugs in the gastrointestinal tract, forming complexes that reduce absorption. Concomitant zinc supplements decrease zinc bioavailability. Administration should be separated by at least 2 hours (sucralfate usually 1 hour before meals), also spacing other oral medicines, since sucralfate interferes with many of them.
Sucralfate + zinc: sucralfate binds zinc and reduces its absorption. Separate by 2 h.
The sucralfate film binds metal cations in the stomach.
Effectiveness of zinc supplementation.
No acute symptoms; deficiency with long-term use.
Separate dosing by at least 2 hours.
DailyMed (FDA) — approved Sucralfate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e781cc0-24ec-4028-8262-dcef9873ea1f ; 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)
Sucralfate reduces levothyroxine absorption, compromising hypothyroidism control.
The sucralfate label documents that simultaneous administration "reduced the extent of absorption (bioavailability) of single doses of... l-thyroxine" and that "dosing the concomitant medication 2 hours before sucralfate eliminated the interaction". Sucralfate forms an adherent barrier on the gastric and duodenal mucosa and may chemically adsorb levothyroxine, preventing its absorption in the proximal duodenum. This interaction is relevant in hypothyroid patients starting sucralfate for peptic ulcer or GERD (especially in the context of critical illness or polypharmacy). Administer levothyroxine on an empty stomach (30–60 minutes before breakfast) and sucralfate at least 2 hours later (ideally a 4-hour interval); monitor TSH 6–8 weeks after starting, adjusting or stopping sucralfate.
Levothyroxine + sucralfate: sucralfate adsorbs levothyroxine and reduces its absorption. Separate administration by 4+ hours (sucralfate 2h after levothyroxine).
Chelation/adsorption of levothyroxine by sucralfate in the gut.
Monitor TSH and hypothyroidism symptoms.
Decompensated hypothyroidism.
Separate administration times (4 hours) and monitor TSH.
DailyMed (FDA) — approved Sucralfate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e781cc0-24ec-4028-8262-dcef9873ea1f ; approved Levothyroxine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=55f4c679-86cb-b97f-e063-6294a90ad5ef — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
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)
Sucralfate may reduce digoxin absorption, decreasing its effect.
Sucralfate forms a viscous gel that binds several drugs in the gastrointestinal tract, including digoxin, reducing its absorption and efficacy. The interaction is avoidable by separating doses: give digoxin at least 2 hours before sucralfate (some sources recommend longer). Separate the administrations, monitor the clinical response (rate control, heart failure signs) and, in stable patients with known levels, consider checking digoxin levels after sucralfate is introduced.
Sucralfate binds digoxin in the GI tract and reduces its absorption. Separate dosing by 2 hours and monitor the clinical response.
Sucralfate binding to digoxin in the gut reduces its bioavailability.
Monitor heart rate and heart failure symptoms.
Loss of rhythm/heart failure control.
Separate administration times (2 hours) and monitor levels/response.
DailyMed (FDA) — approved Sucralfate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e781cc0-24ec-4028-8262-dcef9873ea1f ; approved Digoxin label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=e61d2108-d871-44c0-b12a-2e61fbb56967 — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Food (proteins) may reduce sucralfate binding to the mucosa and its protective effect.
Take on an empty stomach, 1 hour before meals and at bedtime.
DailyMed (FDA) — approved Sucralfate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e781cc0-24ec-4028-8262-dcef9873ea1f
Sucralfate contains aluminium, which may accumulate in renal impairment, with a risk of toxicity (encephalopathy, osteomalacia).
Avoid prolonged use or high doses in severe renal disease; consider alternatives.
DailyMed (FDA) — approved Sucralfate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e781cc0-24ec-4028-8262-dcef9873ea1f
Sucralfate has minimal systemic absorption and is considered low risk in pregnancy.
Can be used in all trimesters if needed.
Excretion into breast milk is negligible; compatible with breastfeeding.
No specific additional contraception.
DailyMed (FDA) — approved Sucralfate label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e781cc0-24ec-4028-8262-dcef9873ea1f
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Cytoprotective agent acting locally on the gastrointestinal mucosa: forms an adherent complex with the proteinaceous exudate of the ulcer, creating a barrier that prevents hydrogen ion diffusion and protects the mucosa from acid, pepsin and bile salts. Accelerates duodenal ulcer healing.
Under acidic conditions, sucralfate polymerises and binds electrostatically to the positively charged proteins of the ulcer exudate (formation of an adherent gel); the resulting film is a physical barrier to hydrogen ion diffusion and adsorbs pepsin and bile salts.
Gastrointestinal absorption is minimal (<5%), so the action is essentially local; adherent gel formation requires acidic pH — administer on an empty stomach (1 hour before meals and at bedtime), when gastric pH is lowest.
Sucralfate is only minimally absorbed; small amounts of the absorbed sulphated disaccharide are excreted primarily in the urine. Most of the dose remains in the gastrointestinal tract and is eliminated in the faeces.
Half-life is not clinically relevant given the local effect and minimal absorption; the drug remains in the gastrointestinal tract until eliminated in the faeces. By local interaction (adsorption), it reduces the absorption of several drugs administered at the same time.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
