Citric Acid

Mechanism-of-action class: Alkylating Activity.

• Uses For the relief of Heartburn, acid indigestion, and upset stomach associated with these symptoms.

Directions Adults 18 years of age and over: take up 1 chewable and repeat every 6 to 8 hours or as directed by a physician Do not swallow whole

Do not take more than 4 chewables in a 24-hour period, or use the maximum dosage of this product for more than 2 weeks except under the advice and supervision of a physician Do not use Do not take more than 4 chewables in a 24-hour period, or use the maximum dosage of this product for more than 2 weeks except under the advice and supervision of a physician Ask a doctor before use if you are Presently taking a prescription drug, Antacids may interact with certain prescription drugs Stop using and ask a doctor if Presently taking a prescription drug, Antacids may interact with certain prescription drugs If pregnant or breast-feeding consult a health professional before use Keep out of reach of children In case of overdose seek medical help or contact a poison control center right away Keep out of reach of children In case of overdose, seek medical help or contact a poison control center right away

Keep out of reach of children In case of overdose, seek medical help or contact a poison control center right away

• Oct 2, 1990NDANDA019481United Guardian
• Dec 17, 2002NDANDA021314Meridian Bioscience
• Nov 28, 2017NDANDA209589Ferring Pharms Inc
• May 22, 2020NDANDA208352Evofem Inc

1. 1Drug Ineffective38217%
2. 2Nausea25411%
3. 3Off Label Use1828.0%
4. 4Vomiting1797.9%
5. 5Headache1777.8%
6. 6Pain1456.4%
7. 7Diarrhoea1265.5%
8. 8Abdominal Pain1215.3%
9. 9Drug Hypersensitivity1175.1%
10. 10Constipation1165.1%
11. 11Anaemia1145.0%
12. 12Fatigue1054.6%
13. 13Malaise1024.5%
14. 14Dyspnoea944.1%
15. 15Pyrexia904.0%

Recent PubMed references pinned to Citric Acid as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• The effect and factor analysis of potassium sodium hydrogen citrate on the formation of double J tube wall stones after ureteral stone surgery.
  Pakistan journal of pharmaceutical sciences · 2026 · Li G, Luo X
  PMID 42262208DOI 10.36721/PJPS.2026.39.8.234.1
• Integrative co-application of citric acid and halotolerant/halophilic citrate-utilizing PGPR enhances leaf ionic homeostasis, productivity, and quality of Vitis vinifera L. in saline-calcareous soils.
  BMC plant biology · 2026 · Abdel Samad AGA, Ibrahim IM, Beheiry HR, et al.
  PMID 42243708DOI 10.1186/s12870-026-09150-0
• Insight into the role of citric acid in modulating retrogradation behavior and physicochemical properties of rice flour during short and long-term storage.
  Carbohydrate polymers · 2026 · Cho DH, Ha M, Jun DS, et al.
  PMID 42173565DOI 10.1016/j.carbpol.2025.124657
• Near-complete phosphorus valorization from sewage sludge: Cost-effective co-production of vivianite and bioavailable detoxified hydrochar via a recyclable citric acid-mediated hydrothermal process.
  Water research · 2026 · Cui X, Jin Y, Zhu J, et al.
  PMID 42172682DOI 10.1016/j.watres.2026.126149
• Glyoxysomal Citrate Synthase Functions in Fluoride Accumulation in Tea Plants by Mediating Citrate Biosynthesis.
  Journal of agricultural and food chemistry · 2026 · Liu Y, Cao D, Hu X, et al.
  PMID 42169425DOI 10.1021/acs.jafc.6c00983
• Citric acid alters Arabidopsis root morphology and development through ROS-dependent and ROS-independent mechanisms.
  Plant physiology · 2026 · Zhang T, Peng JT, Chu J, et al.
  PMID 42160262DOI 10.1093/plphys/kiag194
• Citric acid‑carbon dot mediated cellulose acetate based biodegradable polymeric nanocomposite film for processing and packaging of agro food products.
  International journal of biological macromolecules · 2026 · Hazarika KK, Konwar A, Baruah S, et al.
  PMID 42155743DOI 10.1016/j.ijbiomac.2026.152606
• Preanalytical Quality Evaluation of Low-Volume Citrate Evacuated Blood Collection Tubes-Anticoagulant Solution Volume Accuracy, pH, and Anionic-Cationic Composition.
  Molecules (Basel, Switzerland) · 2026 · Gros N, Hriberšek Z
  PMID 42123879DOI 10.3390/molecules31091516

The 10 most recently updated of 776 ClinicalTrials.gov registrations naming Citric Acid as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• A Study Using Nivolumab, in Combination With Chemotherapy Drugs to Treat Nasopharyngeal Carcinoma (NPC)
  Recruiting · Phase 2 · Interventional · 50 enrolled · National Cancer Institute (NCI)
  NCT06064097updated 2026-06-12
• Testing the Addition of a Type of Drug Called Immunotherapy to the Usual Chemotherapy Treatment for Non-small Cell Lung Cancer, an ALCHEMIST Treatment Trial (Chemo-IO [ACCIO])
  Recruiting · Phase 3 · Interventional · 1,210 enrolled · National Cancer Institute (NCI)
  NCT04267848updated 2026-06-12
• Testing Docetaxel-Cetuximab or the Addition of an Immunotherapy Drug, Atezolizumab, to the Usual Chemotherapy and Radiation Therapy in High-Risk Head and Neck Cancer
  Recruiting · Phase 2 · Phase 3 · Interventional · 613 enrolled · National Cancer Institute (NCI)
  NCT01810913updated 2026-06-12
• Dinutuximab With Chemotherapy, Surgery and Stem Cell Transplantation for the Treatment of Children With Newly Diagnosed High Risk Neuroblastoma
  Recruiting · Phase 3 · Interventional · 478 enrolled · National Cancer Institute (NCI)
  NCT06172296updated 2026-06-12
• Impact of Treatment With Rituximab on the Progression of Humoral Acute Rejection After Renal Transplantation
  Completed · Phase 3 · Interventional · 40 enrolled · University Hospital, Tours
  NCT01350882updated 2026-06-12
• Testing the Addition of MEDI4736 (Durvalumab) to Chemotherapy Before Surgery for Patients With High-Grade Upper Urinary Tract Cancer
  Recruiting · Phase 2 · Phase 3 · Interventional · 131 enrolled · National Cancer Institute (NCI)
  NCT04628767updated 2026-06-11
• Venetoclax, MLN9708 (Ixazomib Citrate) and Dexamethasone for the Treatment of Relapsed or Refractory Light Chain Amyloidosis
  Active not recruiting · Phase 1 · Interventional · 24 enrolled · National Cancer Institute (NCI)
  NCT04847453updated 2026-06-11
• Testing the Addition of an Anti-Cancer Drug, TRC102, to the Usual Chemotherapy Treatment (Pemetrexed, Cisplatin or Carboplatin) During Radiation Therapy for Stage III Non-Squamous Non-Small Cell Lung Cancer
  Recruiting · Phase 2 · Interventional · 42 enrolled · National Cancer Institute (NCI)
  NCT05198830updated 2026-06-11
• Testing the Addition of BMS-986016 (Relatlimab) to the Usual Immunotherapy After Initial Treatment for Recurrent or Metastatic Nasopharyngeal Cancer
  Recruiting · Phase 2 · Interventional · 156 enrolled · National Cancer Institute (NCI)
  NCT06029270updated 2026-06-11
• Preoperative Durvalumab, Cisplatin, Gemcitabine With or Without Futibatinib Targeted Therapy for the Treatment of Resectable Intrahepatic Cholangiocarcinoma, OPTIC Trial
  Not yet recruiting · Phase 2 · Interventional · 44 enrolled · Northwestern University
  NCT07639528updated 2026-06-10

Frequently asked questions

How does Citric Acid work?

Mechanism-of-action class: Alkylating Activity.

What is Citric Acid used for?

According to FDA labeling, Citric Acid carries indications including: Uses For the relief of Heartburn, acid indigestion, and upset stomach associated with these symptoms.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Citric Acid?

Citric Acid is classified as Acid preparations, Alkylating Activity, Increased Renal HCO3- Excretion.

What are the brand names for Citric Acid?

Citric Acid is marketed under brand names including Alka-Seltzer, Bromo Seltzer Antacid Pain Reliever, Clenpiq, Cytra 2, Cytra-3, Cytra-K, E-Z-Gas II, Oracit.