{"ok":true,"entry":{"slug":"tadalafil","kind":"medication","name":"tadalafil","aliases":["Cialis"],"brands_sg":["Cialis","Synerrv","Tadafil","Tadaccord","Tadilas"],"class":"PDE5 inhibitor","tags":["other"],"use_for":"healthhub: erectile dysfunction, enlarged prostate, pah","use_after":"healthhub: as-needed dosing works from 30 min to 36 hours","use_duration":null,"take_with":"healthhub: with or without food · grapefruit interacts","pros":["healthhub: effective for up to 36 hours","sg label: 5 mg daily covers ed and enlarged prostate","healthhub: taken with or without food"],"cons":["healthhub: flushing, headache, nasal congestion","sg label: any organic nitrate is a contraindication","healthhub: rare priapism, sudden vision or hearing loss"],"dose_note":"the singapore label for cialis tablet states, for as-needed use in erectile dysfunction, 'The recommended dose is 10mg taken prior to anticipated sexual activity … the maximum dose is 20mg and the maximum dosing frequency is once per day'. the same label lowers that ceiling to 10 mg once every 48 hours in moderate renal impairment, 5 mg once every 72 hours in severe renal impairment, and 10 mg once every 72 hours (2.5 mg for once-daily use) alongside strong cyp3a4 inhibitors such as ketoconazole or ritonavir. for once-daily use in enlarged prostate the stated doses are 2.5–5 mg. in singapore the prescriber sets the dose.","dosage":null,"ul_status":null,"sg_class":"prescription-only","cautions":["healthhub: recent stroke or heart attack, or low blood pressure","sg label: cardiac disease making sexual activity inadvisable","healthhub: severe heart, liver or kidney problems","healthhub: retinitis pigmentosa, or past sudden vision loss"],"clashes":[{"src":["ndf_cia_ci","hh_tad_prec"],"note":"contraindicated on the sg label; healthhub warns of a dangerous fall in blood pressure","with":"nitrates (gtn, isosorbide mono- or dinitrate)"},{"src":["hh_tad_prec"],"note":"healthhub: the combination may further lower blood pressure","with":"alpha-1 blockers (tamsulosin, terazosin, prazosin, alfuzosin)"},{"src":["ndf_cia_ci"],"note":"co-administration is contraindicated on the sg label","with":"riociguat and other guanylate cyclase stimulators"},{"src":["ndf_cia_cyp"],"note":"sg label caps the dose at 10 mg, not more than once every 72 hours","with":"strong cyp3a4 inhibitors (ketoconazole, ritonavir)"},{"src":["hh_tad_avoid"],"food":true,"note":"healthhub: may interact and increase the risk of side-effects","with":"grapefruit and grapefruit juice"}],"sources":[{"id":"hsa_register","url":"https://data.gov.sg/datasets/d_767279312753558cbf19d48344577084/view","label":"HSA — Listing of Registered Therapeutic Products (data.gov.sg open dataset, 5,511 rows, cached in full and filtered locally)","quote":"All 32 registered tadalafil products read Forensicclassification 'Prescription Only' — SIN12181P CIALIS TABLET 20 mg · SIN13632P CIALIS TABLET 5 mg · SIN16839P SYNERRV · SIN16131P TADAFIL 20 · SIN16072P TADACCORD 20 · SIN16580P TADILAS","accessed":"2026-08-27"},{"id":"hh_tad_uses","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/tadalafil","label":"HealthHub (National Medication Information workgroup, SG) — Tadalafil: what is this medication for","quote":"Tadalafil is used to treat erectile dysfunction … It can also be used for urinary symptoms associated with benign prostatic hyperplasia (enlarged prostate) … Tadalafil is also used to treat high blood pressure in the blood vessels in the lungs","accessed":"2026-08-27"},{"id":"hh_tad_admin","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/tadalafil","label":"HealthHub — Tadalafil: how should I take this medication","quote":"When taking this medication on an as-needed basis, take before sexual activity. It starts to work within 30 minutes and is effective for up to 36 hours … This medication may be taken with or without food.","accessed":"2026-08-27"},{"id":"hh_tad_se","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/tadalafil","label":"HealthHub — Tadalafil: common side effects","quote":"Facial flushing where the skin on your face feels hot; Giddiness due to lowering of blood pressure; Headache; Nausea; Back pain, muscle aches, pain in arms and legs; Nasal congestion","accessed":"2026-08-27"},{"id":"hh_tad_rare","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/tadalafil","label":"HealthHub — Tadalafil: rare but serious side effects","quote":"Priapism (an erection that will not go away) … Sudden vision loss in one or both eyes can be a sign of a serious eye problem called non-arteritic anterior ischemic optic neuropathy (NAION). Sudden hearing decrease or hearing loss","accessed":"2026-08-27"},{"id":"hh_tad_prec","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/tadalafil","label":"HealthHub — Tadalafil: precautions on nitrates and alpha-blockers","quote":"The combination of nitrates with tadalafil may lead to a dangerous fall in your blood pressure … You are taking medicines called Alpha-1 Blockers (such as Tamsulosin, Terazosin, Prazosin, Alfuzosin), as the combination may further lower your blood pressure.","accessed":"2026-08-27"},{"id":"hh_tad_prec2","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/tadalafil","label":"HealthHub — Tadalafil: what precautions should I take","quote":"You recently had a stroke or a heart attack, low blood pressure or uncontrolled high blood pressure. You have severe heart, liver or kidney problem. You have certain rare inherited eye diseases (such as retinitis pigmentosa)","accessed":"2026-08-27"},{"id":"hh_tad_avoid","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/tadalafil","label":"HealthHub — Tadalafil: what food or medication should I avoid","quote":"Avoid taking grapefruit, or grapefruit juice as they may interact with your medication and increase the risk of side-effects.","accessed":"2026-08-27"},{"id":"ndf_cia_ind","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12181p/","label":"Singapore National Drug Formulary (HSA/MOH) — CIALIS TABLET 20 MG [SIN12181P], section 4.1 Therapeutic indications","quote":"Treatment of erectile dysfunction (ED) in adult males … Treatment of the signs and symptoms of benign prostatic hyperplasia (BPH) … Cialis is not indicated for use by women.","accessed":"2026-08-27"},{"id":"ndf_cia_dose","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12181p/","label":"Singapore National Drug Formulary — CIALIS TABLET 20 MG [SIN12181P], section 4.2 Posology, Cialis for Use as Needed","quote":"The recommended dose is 10mg taken prior to anticipated sexual activity. In those patients in whom tadalafil 10mg does not produce an adequate effect, the maximum dose is 20mg and the maximum dosing frequency is once per day.","accessed":"2026-08-27"},{"id":"ndf_cia_bph","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12181p/","label":"Singapore National Drug Formulary — CIALIS TABLET 20 MG [SIN12181P], BPH and ED/BPH dosing","quote":"Benign Prostatic Hyperplasia: The recommended dose is 5mg, taken at approximately the same time every day … Erectile Dysfunction and Benign Prostatic Hyperplasia: The recommended dose is 5mg","accessed":"2026-08-27"},{"id":"ndf_cia_renal","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12181p/","label":"Singapore National Drug Formulary — CIALIS TABLET 20 MG [SIN12181P], men with renal impairment","quote":"Moderate (creatinine clearance 31 to 50 ml/min): … the maximum dose is 10mg not more than once in every 48 hours. Severe … The maximum dose is 5mg not more than once in every 72 hours","accessed":"2026-08-27"},{"id":"ndf_cia_cyp","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12181p/","label":"Singapore National Drug Formulary — CIALIS TABLET 20 MG [SIN12181P], patients taking CYP3A4 inhibitors","quote":"For patients taking concomitant potent inhibitors of CYP3A4, such as ketoconazole or ritonavir, the maximum recommended dose of Cialis is 10mg, not to exceed once every 72 hours","accessed":"2026-08-27"},{"id":"ndf_cia_ci","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12181p/","label":"Singapore National Drug Formulary — CIALIS TABLET 20 MG [SIN12181P], section 4.3 Contraindications (nitrates, riociguat)","quote":"administration of Cialis to patients who are using any form of organic nitrate is contraindicated … The co-administration of PDE5 inhibitors, including tadalafil, with guanylate cyclase stimulators, such as riociguat, is contraindicated","accessed":"2026-08-27"},{"id":"ndf_cia_ci2","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin12181p/","label":"Singapore National Drug Formulary — CIALIS TABLET 20 MG [SIN12181P], cardiac and ocular contraindications","quote":"Cialis must not be used in men with cardiac disease for whom sexual activity is inadvisable … Cialis is contraindicated in patients who have loss of vision in one eye because of non-arteritic anterior ischaemic optic neuropathy (NAION)","accessed":"2026-08-27"}],"brand_certs":null,"updated_at":"2026-08-29T16:16:33.302383+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}