Generic Medicine Info
Indications and Dosage
Erectile dysfunction
Adult: Initially, 10 mg as needed, at least 30 min before sexual intercourse, may be increased to 20 mg, depending on response. Alternatively, 5 mg once daily, taken at the same time each day, may be decreased to 2.5 mg, depending on response. Max dosing frequency: Once every 24 hr.

Benign prostatic hyperplasia
Adult: 5 mg once daily, taken at the same time each day.

Pulmonary arterial hypertension
Adult: 40 mg once daily.
Special Patient Group
Benign prostatic hyperplasia: Patients taking CYP3A4 inhibitors (e.g. azole antifungals and protease inhibitors): Max: 10 mg once every 72 hr, as needed.

Erectile dysfunction: Patients taking CYP3A4 inhibitors (e.g. azole antifungals and protease inhibitors): Max: 2.5 mg once every 24 hr.

Pulmonary arterial hypertension: Patients taking ritonavir or other HIV protease inhibitors: 20 mg once daily, increased to 40 mg once daily as tolerated.
Renal Impairment
Erectile dysfunction: Patient on haemodialysis: Max: 5 mg once every 72 hr; regular daily dosing is not recommended.
CrCl (mL/min) Dosage
<30 Max: 5 mg once every 72 hr; regular daily dosing is not recommended.
Initially, 5 mg once daily. Max: 10 mg once every 48 hr.

Benign prostatic hyperplasia: Patient on haemodialysis: Not recommended.
CrCl (mL/min) Dosage
<30 Not recommended.
Initially, 2.5 mg once daily. Max: 5 mg.

Pulmonary arterial hypertension:
CrCl (mL/min) Dosage
<30 Contraindicated.
Initially, 20 mg once daily, increased to 40 mg once daily, according to tolerability.
Hepatic Impairment
Erectile dysfunction: Mild to moderate (Child-Pugh class A or B): Max: 10 mg once daily, as needed. Severe (Child-Pugh class C): Not recommended.

Benign prostatic hyperplasia: Severe (Child-Pugh class C): Not recommended.

Pulmonary arterial hypertension: Mild to moderate (Child-Pugh class A or B): Initially, 20 mg once daily. Severe (Child-Pugh class C): Contraindicated.
May be taken with or without food.
Hypotension, mild to severe heart failure, acute recent MI; other conditions wherein sexual activity is inadvisable; recent stroke, uncontrolled arrhythmias and/or HTN, unstable angina, vision loss due to non-arteritic anterior ischaemic optic neuropathy (NAION). Severe hepatic impairment (Child-Pugh class C) when used for pulmonary arterial hypertension. Concomitant use of any form of organic nitrates, nitric oxide donors, and guanylate cyclase stimulators.
Special Precautions
Patient w/ retinitis pigmentosa, left ventricular outflow obstruction (aortic stenosis or hypertrophic obstructive cardiomyopathy), anatomical penile deformation, conditions which may be predisposed to priapism (e.g. sickle cell anaemia, multiple myeloma, leukemia); bleeding disorders, peptic ulcer disease, pulmonary veno-occlusive disease. Renal and hepatic impairment. Pregnancy and lactation.
Adverse Reactions
Significant: Hypotension, TIA, anginal chest pain, palpitations, tachycardia, color discrimination impairment, vision loss/NAION, sudden decrease or loss of hearing, tinnitus, dizziness. Rarely, prolonged/painful erection or priapism.
Nervous: Headache, dizziness, fatigue. Rarely, transient amnesia.
CV: HTN, flushing, peripheral oedema.
GI: Nausea, dyspepsia, abdominal pain, vomiting, diarrhoea, gastroenteritis, GERD.
Resp: Nasopharyngitis, nasal congestion, dyspnoea, cough, epistaxis, resp tract infection.
Haematologic: Haematuria.
Musculoskeletal: Myalgia, back and limb pain, pain in extremities.
Otic: Tinnitus.
Ophthalmologic: Blurred vision, eye pain.
Dermatologic: Rash.
Immunologic: Hypersensitivity.
Potentially Fatal: Serious CV events (e.g. MI, stroke, sudden cardiac death, unstable angina pectoris, ventricular arrhythmia).
Assess CV status prior to initiation of therapy. Monitor BP.
Drug Interactions
May enhance hypotensive effect of α1-adrenergic blockers, and other antihypertensive drugs (e.g. amlodipine, enalapril, metoprolol, bendrofluazide). Increased serum concentration w/ CYP3A4 inhibitors (e.g. azole antifungals, macrolides, HIV protease inhibitors, cimetidine). Decreased serum concentration w/ CYP3A4 inducers (e.g. rifampin, carbamazepine, phenytoin, phenobarbital).
Potentially Fatal: Enhanced hypotensive effect w/ any form of organic nitrates, guanylate cyclase stimulators (e.g. riociguat).
Food Interaction
Increased serum levels/toxicity w/ grapefruit juice. Increased risk of symptomatic hypotension w/ alcohol.
Description: Tadalafil is a phosphodiesterase inhibitor w/ the greatest selectivity for PDE type 5, which is responsible for the metabolism of cyclic guanosine monophosphate (cGMP) in the smooth muscle. Inhibition leads to: increase in cGMP levels causing smooth muscle relaxation and increased blood flow into the corpus cavernosum of the penis during sexual stimulation thereby producing an erection; relaxation of smooth muscle in the pulmonary vascular bed causing vasodilation and reduction in pulmonary vascular resistance; relaxation of smooth muscle or increased blood perfusion in the bladder and prostate.
Onset: W/in 1 hr. Pulmonary artery vasodilation: 75-90 min.
Duration: Erectile dysfunction: Up to 36 hr.
Absorption: Well absorbed from the GI tract. Time to peak plasma concentration: Approx 2 hr (range: 30 min to 6 hr).
Distribution: Widely distributed in the tissues. Detected in the semen. Volume of distribution: 63-77 L. Plasma protein binding: Approx 94%.
Metabolism: Metabolised in the liver primarily by CYP3A4 via methylation and glucuronidation to form inactive metabolites methylcatechol and methylcatechol glucuronide respectively.
Excretion: Mainly via faeces (approx 61%, as metabolites); urine (lesser extent, approx 36%, as metabolites). Elimination half-life: 15-17.5 hr.
Chemical Structure

Chemical Structure Image

Source: National Center for Biotechnology Information. PubChem Database. Tadalafil, CID=110635, https://pubchem.ncbi.nlm.nih.gov/compound/Tadalafil (accessed on Jan. 23, 2020)

Store below 25°C.
ATC Classification
G04BE08 - tadalafil ; Belongs to the class of drugs used in erectile dysfunction.
Anon. Tadalafil. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 11/10/2017.

Buckingham R (ed). Tadalafil. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 11/10/2017.

Cialis Tablet, Film Coated (Eli Lilly and Company). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 11/10/2017.

Joint Formulary Committee. Tadalafil. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 11/10/2017.

McEvoy GK, Snow EK, Miller J et al (eds). Tadalafil. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 11/10/2017.

Disclaimer: This information is independently developed by MIMS based on Tadalafil from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by MIMS.com
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