Citrate
/api/v1/drug/citrateMechanism of action
Sourced from openFDAThe physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. NO then activates the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate (cGMP), producing smooth muscle relaxation in the corpus cavernosum and allowing inflow of blood.
Indications
Sourced from openFDA- Sildenafil tablets are indicated for the treatment of erectile dysfunction.ICD-10: N52.9
Contraindications
Sourced from openFDA- Administration of sildenafil tablets to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form. Sildenafil tablets was shown to potentiate the hypotensive effect of nitrates ( 4.1 , 7.1 , 12.2 ) Known hypersensitivity to sildenafil or any component of tablet ( 4.2 ) Administration with guanylate cyclase (GC) stimulators, such as riociguat ( 4.3 ) 4.1 Nitrates Consistent with its known effects on the nitric oxide/cGMP pathway [ see Clinical Pharmacology (12.1 , 12.2 ) ], sildenafil tablets was shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are using nitric oxide donors such as organic nitrates or organic nitrites in any form either regularly and/or intermittently is therefore contraindicated.contraindicated
Dosage & administration
Sourced from openFDAFor most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity ( 2.1 ) Based on effectiveness and toleration, may increase to a maximum of 100 mg or decrease to 25 mg ( 2.1 ) Maximum recommended dosing frequency is once per day ( 2.1 ) 2.1 Dosage Information For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity. The maximum recommended dosing frequency is once per day. Based on effectiveness and toleration, the dose may be increased to a maximum recommended dose of 100 mg or decreased to 25 mg. 2.2 Use with Food Sildenafil tablets may be taken with or without food. 2.3 Dosage Adjustments in Specific Situations Sildenafil tablets was shown to potentiate the hypotensive effects of nitrates and its administration in patients who use nitric oxide donors such as organic nitrates or organic nitrites in any form is therefore contraindicated [ see Contraindications (4.1) , Drug Interactions (7.1) , and Clinical Pharmacology (12.2) ]. When sildenafil tablets are co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating sildenafil tablets treatment and sildenafil tablets should be initiated at 25 mg [ see Warnings and Precautions (5.5) , Drug Interactions (7.2) , and Clinical Pharmacology (12.2) ].
Warnings & precautions
Sourced from openFDAPatients should not use sildenafil if sexual activity is inadvisable due to cardiovascular status ( 5.1 ) Patients should seek emergency treatment if an erection lasts >4 hours. Use sildenafil with caution in patients predisposed to priapism ( 5.2 ) Patients should stop sildenafil tablets and seek medical care if a sudden loss of vision occurs in one or both eyes, which could be a sign of non arteritic anterior ischemic optic neuropathy (NAION). Sildenafil tablets should be used with caution, and only when the anticipated benefits outweigh the risks, in patients with a history of NAION. Patients with a "crowded" optic disc may also be at an increased risk of NAION. ( 5.3 ) Patients should stop sildenafil tablets and seek prompt medical attention in the event of sudden decrease or loss of hearing ( 5.4 ) Caution is advised when sildenafil is co-administered with alpha-blockers or anti-hypertensives. Concomitant use may lead to hypotension ( 5.5 ) Decreased blood pressure, syncope, and prolonged erection may occur at higher sildenafil exposures. In patients taking strong CYP inhibitors, such as ritonavir, sildenafil exposure is increased. Decrease in sildenafil dosage is recommended ( 2.4 , 5.6 ) 5.1 Cardiovascular There is a potential for cardiac risk of sexual activity in patients with preexisting cardiovascular disease. Therefore, treatments for erectile dysfunction, including sildenafil, should not be generally used in men for whom sexual activity is inadvisable because of their underlying cardiovascular status.
Adverse reactions
Sourced from openFDAThe following are discussed in more detail in other sections of the labeling: Cardiovascular [ see Warnings and Precautions (5.1) ] Prolonged Erection and Priapism [ see Warnings and Precautions (5.2) ] Effects on the Eye [ see Warnings and Precautions (5.3) ] Hearing Loss [ see Warnings and Precautions (5.4) ] Hypotension when Co-administered with Alpha-blockers or Anti-hypertensives [ see Warnings and Precautions (5.5) ] Adverse Reactions with the Concomitant Use of Ritonavir [ see Warnings and Precautions (5.6) ] Combination with other PDE5 Inhibitors or Other Erectile Dysfunction Therapies [ see Warnings and Precautions (5.7) ] Effects on Bleeding [ see Warnings and Precautions (5.8) ] Counseling Patients About Sexually Transmitted Diseases [ see Warnings and Precautions (5.9) ] The most common adverse reactions reported in clinical trials (≥ 2%) are headache, flushing, dyspepsia, abnormal vision, nasal congestion, back pain, myalgia, nausea, dizziness, and rash. Most common adverse reactions (≥ 2%) include headache, flushing, dyspepsia, abnormal vision, nasal congestion, back pain, myalgia, nausea, dizziness and rash ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Nivagen Pharmaceuticals, Inc. at 1-877-977-0687 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.
Use in specific populations
Sourced from openFDAGeriatric use: Consider a starting dose of 25 mg ( 2.5 , 8.5 ) Severe renal impairment: Consider a starting dose of 25 mg ( 2.5 , 8.6 ) Hepatic impairment: Consider a starting dose of 25 mg ( 2.5 , 8.7 ) 8.1 Pregnancy Risk Summary Sildenafil is not indicated for use in females. There are no data with the use of sildenafil in pregnant women to inform any drug-associated risks for adverse developmental outcomes. Animal reproduction studies conducted with sildenafil did not show adverse developmental outcomes when administered during organogenesis in rats and rabbits at oral doses up to 16 and 32 times, respectively, the maximum recommended human dose (MRHD) of 100 mg/day on a mg/m 2 basis ( see Data ). Data Animal Data No evidence of teratogenicity, embryotoxicity or fetotoxicity was observed in rats and rabbits which received oral doses up to 200 mg/kg/day during organogenesis. These doses represent, respectively, about 16 and 32 times the MRHD on a mg/m 2 basis in a 50 kg subject. In the rat pre- and postnatal development study, the no observed adverse effect dose was 30 mg/kg/day given for 36 days, about 2 times the MRHD on a mg/m 2 basis in a 50 kg subject. 8.2 Lactation Risk Summary Sildenafil is not indicated for use in females. Limited data indicate that sildenafil and its active metabolite are present in human milk.
Pharmacokinetics
Sourced from openFDA- Metabolism
- Sildenafil is rapidly absorbed after oral administration, with a mean absolute bioavailability of 41% (range 25-63%). The pharmacokinetics of sildenafil are dose-proportional over the recommended dose range.
Overdosage
Sourced from openFDAIn studies with healthy volunteers of single doses up to 800 mg, adverse reactions were similar to those seen at lower doses but incidence rates and severities were increased. In cases of overdose, standard supportive measures should be adopted as required. Renal dialysis is not expected to accelerate clearance as sildenafil is highly bound to plasma proteins and it is not eliminated in the urine.
Approval history
Sourced from openFDA- Feb 1, 1979NDANDA018058Curium
- Jul 11, 1984NDANDA019101Hikma
- Jan 12, 1985NDANDA019115Hospira
- Aug 30, 1985NDANDA019071Mission Pharma
- May 29, 1997NDANDA020497Kyowa Kirin
- Mar 27, 1998NDANDA020895Viatris
- Nov 4, 1998NDANDA020747Cephalon
- Sep 21, 1999NDANDA020793Hikma
FAERS reports
- 1Drug Ineffective22,99611%
- 2Dyspnoea17,0688.1%
- 3Headache15,6677.5%
- 4Nausea15,5297.4%
- 5Fatigue13,2036.3%
- 6Dizziness12,3895.9%
- 7Death12,3575.9%
- 8Pain11,7555.6%
- 9Diarrhoea11,5095.5%
- 10Off Label Use10,4525.0%
- 11Vomiting8,4434.0%
- 12Paraesthesia7,9853.8%
- 13Condition Aggravated7,6943.7%
- 14Malaise7,6313.6%
- 15Pneumonia7,6223.6%
Literature
Recent PubMed references pinned to Citrate 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 XPMID 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 ZPMID 42123879DOI 10.3390/molecules31091516
Clinical trials
The 10 most recently updated of 2,290 ClinicalTrials.gov registrations naming Citrate as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.
- Evaluating the Addition of the Immunotherapy Drug Atezolizumab to Standard Chemotherapy Treatment for Advanced or Metastatic Neuroendocrine Carcinomas That Originate Outside the LungRecruiting · Phase 2 · Phase 3 · Interventional · 189 enrolled · National Cancer Institute (NCI)NCT05058651updated 2026-06-12
- A Study to Test the Addition of the Drug Cabozantinib to Chemotherapy in Patients With Newly Diagnosed OsteosarcomaRecruiting · Phase 2 · Phase 3 · Interventional · 1,122 enrolled · National Cancer Institute (NCI)NCT05691478updated 2026-06-12
- 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 the Addition of Cemiplimab (REGN2810) to Chemotherapy Treatment Given Prior to Surgery in Patients With Sinonasal Squamous Cell CarcinomaRecruiting · Phase 2 · Interventional · 108 enrolled · National Cancer Institute (NCI)NCT07281417updated 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 CancerRecruiting · 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 NeuroblastomaRecruiting · 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 TransplantationCompleted · Phase 3 · Interventional · 40 enrolled · University Hospital, ToursNCT01350882updated 2026-06-12
- Hormone Therapy With or Without Combination Chemotherapy in Treating Women Who Have Undergone Surgery for Node-Negative Breast Cancer (The TAILORx Trial)Active not recruiting · Phase 3 · Interventional · 10,273 enrolled · National Cancer Institute (NCI)NCT00310180updated 2026-06-11
- Testing the Addition of MEDI4736 (Durvalumab) to Chemotherapy Before Surgery for Patients With High-Grade Upper Urinary Tract CancerRecruiting · Phase 2 · Phase 3 · Interventional · 131 enrolled · National Cancer Institute (NCI)NCT04628767updated 2026-06-11
Frequently asked questions
- How does Citrate work?
- The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. NO then activates the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate (cGMP), producing smooth muscle relaxation in the corpus cavernosum and allowing inflow of blood.
- What is Citrate used for?
- According to FDA labeling, Citrate carries indications including: Sildenafil tablets are indicated for the treatment of erectile dysfunction.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
- What class of drug is Citrate?
- Citrate is classified as Acid-Base Activity, Increased Renal HCO3- Excretion.
- What are the contraindications for Citrate?
- Citrate labeling lists contraindications including: Administration of sildenafil tablets to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form. Sildenafil tablets was shown to potentiate the hypotensive effect of nitrates ( 4.1 , 7.1 , 12.2 ) Known hypersensitivity to sildenafil or any component of tablet ( 4.2 ) Administration with guanylate cyclase (GC) stimulators, such as riociguat ( 4.3 ) 4.1 Nitrates Consistent with its known effects on the nitric oxide/cGMP pathway [ see Clinical Pharmacology (12.1 , 12.2 ) ], sildenafil tablets was shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are using nitric oxide donors such as organic nitrates or organic nitrites in any form either regularly and/or intermittently is therefore contraindicated.. Always consult the full prescribing information and a clinician.
citrate is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.