Interactions of Sildenafil Medicine.

Sildenafil citrate, commonly known by its brand name Viagra, is a medication primarily used to treat erectile dysfunction. It is also available under various generic brand names. This article provides information about the potential interactions associated with sildenafil citrate.

Medication Class Examples Interaction
Nitrates Nitroglycerin, isosorbide mononitrate, amyl nitrite Contraindicated; severe drop in blood pressure
Alpha-blockers Doxazosin, tamsulosin Potential drop in blood pressure
Other blood pressure drugs Amlodipine, metoprolol, lisinopril Possible potentiation of hypotensive effects
CYP3A4 inhibitors Ketoconazole, erythromycin, cimetidine Increased sildenafil blood levels
CYP3A4 inducers Rifampin, phenytoin, carbamazepine Decreased sildenafil blood levels
Medications for HIV/AIDS Ritonavir, indinavir, saquinavir Increased risk of side effects, adjust dose
Antifungal medications Fluconazole, itraconazole, ketoconazole Increased sildenafil blood levels
Antibiotics Clarithromycin, erythromycin Increased sildenafil blood levels

Sildenafil and Alcohol/Supplements/Food Interactions

Alcohol (Ethanol)  and Sildenafil

  • Increased risk of side effects:
    Both alcohol and sildenafil can cause headaches, dizziness, and low blood pressure. When taken together, these effects can be more pronounced and may lead to fainting or other serious complications.
  • Reduced effectiveness of sildenafil:
    Alcohol can also reduce the effectiveness of sildenafil by interfering with the way the medication is metabolized in the body. This can make it more difficult to achieve and maintain an erection.
  • Increased risk of heart problems:
    Both alcohol and sildenafil can affect the heart, and combining the two can increase the risk of heart problems such as rapid heart rate, palpitations, and even heart attack or stroke.

Sildenafil and Supplements/foods Interactions

  • Grapefruit juice:
    Grapefruit juice can increase the levels of sildenafil in the blood, which can lead to a higher risk of side effects.
  • L-arginine:
    L-arginine is an amino acid that is sometimes used as a supplement for ED. However, taking L-arginine with sildenafil can cause a dangerous drop in blood pressure.
  • Yohimbine:
    Yohimbine is an herbal supplement that is sometimes used for ED. However, taking yohimbine with sildenafil can also cause a drop in blood pressure.

Sildenafil drug interactions

Major drug interactions:

Combining these Medicine with Sildenafil should be avoided due to their high clinical significance.

  • Taking this medication along with sildenafil can cause an elevation in the blood levels and amplification of the effects of sildenafil.
    • Adagrasib
    • Amprenavir (Agenerase)
    • Atazanavir (Reyataz)
    • Boceprevir (Victrelis)
    • Ceritinib (Zykadia)
    • Clarithromycin (Biaxin)
    • Cobicistat (Tybost)
    • Darunavir (Prezista)
    • Delavirdine (Rescriptor)
    • Erythromycin (Erythrocin)
    • Fosamprenavir (Lexiva)
    • Idelalisib (Zydelig)
    • Indinavir (Crixivan)
    • Itraconazole (Sporanox)
    • Ketoconazole (Nizoral)
    • Levoketoconazole
    • Lonafarnib (Zokinvy)
    • Nefazodone (Serzone)
    • Nelfinavir (Viracept)
    • Ritonavir (Norvir)
  • The combination of sildenafil and this medication can result in a significant decrease in blood pressure.
    • Amyl Nitrite
    • Nitroprusside (Nitropress)
    • Riociguat (Adempas)
    • Isosorbide (Isordil, Dilatrate-SR)
    • Avanafil (Stendra)
    • Nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Minitran, Nitro-Bid, Rectiv, GoNitro)

Moderate drug interactions:

This combination is of moderate clinical significance. It is generally advisable to refrain from using combinations, except in unique situations.

  • Amlodipine
  • Lisinopril
  • Hydrochlorothiazide
  • Metoprolol
  • Amiodarone
  • Atorvastatin
  • Losartan
  • Furosemide
  • Levothyroxine
  • Simvastatin
  • Allopurinol
  • Citalopram
  • Gabapentin
  • Omeprazole
  • Metformin
  • Fluoxetine
  • Carvedilol
  • Pantoprazole
  • Azithromycin
  • Warfarin

Sildenafil disease interactions

Disease Interactions that are of high clinical significance.

  • Cardiovascular Disease
    Patients with pre-existing cardiovascular diseases or recent history of heart attack, stroke, or life-threatening arrhythmia within the past six months, resting hypotension (BP < 90/50) or hypertension (BP > 170/110), unstable angina associated with cardiac failure, or coronary artery disease should not use PDE5 inhibitors.
  •  Renal Dysfunction
    Patients with severe renal impairment may experience decreased plasma clearance of phosphodiesterase-5 (PDE5) inhibitors, which can lead to drug accumulation.
    Use of PDE5 inhibitors like sildenafil should be avoided in patients with severe renal disease or who are undergoing renal dialysis.
  • Pulmonary Disease
    Sildenafil helps treat high blood pressure in the lungs, but it can make things worse for people with a certain lung disease called pulmonary veno-occlusive disease (PVOD).

Disease Interactions that are of less clinical significance.

  •   Priapism
  •   Alcoholism
  •   Hearing Loss
  •   Liver Disease
  •   Retinitis Pigmentosa
  •   Seizure Disorders


Medzpills aims to provide consumers with reliable, trustworthy, and expert-reviewed information. This article has been reviewed by Parry Stone, an expert in the field. However, it is important to note that the information presented should not be used as a substitute for the advice of a qualified medical professional. The information provided serves only as a source of knowledge and may not cover all aspects of health conditions, lab tests, medications, potential side effects, drug interactions, warnings, alerts, and more. It is highly recommended to consult with your doctor and address any concerns or questions you may have about a specific disease or medication. At Medzpills, we strive to supplement, rather than replace, the essential doctor-patient relationship.


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