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nirmatrelvir/ritonavir vs tadalafil

Side-by-side comparison of nirmatrelvir/ritonavir and tadalafil. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

moderate Known Drug Interaction

Pulmonary hypertension agents (PDE5 inhibitors) tadalafil (Adcirca ® ) ↑ tadalafil Avoid concomitant use of tadalafil with PAXLOVID for pulmonary hypertension. sildenafil, tadalafil, vardenafil ↑ sildenafil ↑ tadalafil ↑ vardenafil Dosage adjustment is recommended for use of sildenafil, tadalafil or vardenafil with PAXLOVID when used for erectile dysfunction.

Recommendation: Avoid this combination if you take tadalafil for lung pressure, or talk to your doctor about a lower dose if using it for erectile dysfunction.

Drug Class
nirmatrelvir/ritonavir Antiviral (Protease Inhibitor Combination)
tadalafil PDE5 Inhibitor
Type
nirmatrelvir/ritonavir Prescription
tadalafil Prescription
Summary
nirmatrelvir/ritonavir

Paxlovid is a medicine used to treat mild to moderate COVID-19 in adults. It helps prevent severe illness, hospitalization, or death in people at high risk.

tadalafil

Tadalafil (Cialis) is a medicine that helps men with erectile dysfunction (ED) or enlarged prostate (BPH). It belongs to a class of drugs called PDE5 inhibitors.

What It Treats
nirmatrelvir/ritonavir

Paxlovid treats mild to moderate COVID-19 in adults. You must be at high risk of your illness becoming severe. This includes needing to go to the hospital or possibly dying from COVID-19. Paxlovid is not for preventing COVID-19 before or after exposure.

tadalafil

This medicine can help men who have trouble getting or keeping an erection (ED). It can also treat the symptoms of an enlarged prostate, also known as benign prostatic hyperplasia (BPH). BPH can cause difficulty with urination.

How It Works
nirmatrelvir/ritonavir

Paxlovid contains two medicines, nirmatrelvir and ritonavir. Nirmatrelvir stops the virus from multiplying in your body. Ritonavir helps nirmatrelvir stay in your body longer so it can work better.

tadalafil

Tadalafil works by relaxing the muscles in the penis and prostate. This increases blood flow to these areas. For BPH, it relaxes muscles in the prostate and bladder, which can improve urinary symptoms.

Common Side Effects
nirmatrelvir/ritonavir
  • Change in taste
  • Diarrhea
tadalafil
  • Headache
  • Upset stomach
  • Back pain
  • Muscle aches
  • Nasal congestion
FAERS Reports
nirmatrelvir/ritonavir
  • COVID-19 22,774
  • COVID-19 coming back 20,089
  • Change in taste 7,316
  • Diarrhea 4,003
  • Feeling sick to your stomach 2,620
tadalafil
  • Shortness of breath 11,663
  • Headache 10,690
  • Diarrhea 7,800
  • Feeling sick to your stomach 6,498
  • Death 5,896
Serious Warnings
nirmatrelvir/ritonavir

Paxlovid can interact with many other medicines, causing serious or life-threatening problems. Before taking Paxlovid, tell your doctor about all the medicines you take. Your doctor may need to adjust the dose of your other medicines or monitor you more closely.

tadalafil

If you have chest pain, tell your doctor. If you need nitrates for a heart problem, wait 48 hours after taking tadalafil before taking nitrates. If you get an erection that lasts more than 4 hours, get medical help right away. If you have sudden vision loss in one or both eyes, stop taking this medicine and get medical help right away. If you have a sudden decrease or loss of hearing, stop taking this medicine and get medical help right away.

Pregnancy
nirmatrelvir/ritonavir

There is not enough information about nirmatrelvir's safety during pregnancy. Studies on ritonavir in pregnant women have not shown an increased risk of birth defects. Talk to your doctor about the risks and benefits of taking Paxlovid if you are pregnant or breastfeeding.

tadalafil

This medicine is not for use in women. It is not known if this medicine will harm an unborn baby. It is also not known if this medicine passes into breast milk.

Also Compare, Nearby Drugs

Compare tadalafil with

How to Read This nirmatrelvir/ritonavir vs tadalafil Comparison

nirmatrelvir/ritonavir is classified in the Antiviral (Protease Inhibitor Combination) drug class, while tadalafil sits within the PDE5 Inhibitor class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.

Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, nirmatrelvir/ritonavir has 56,802 submissions while tadalafil has 42,547. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known moderate interaction flagged in FDA labeling, attributed to this combination prevents the body from clearing tadalafil, leading to much higher levels of the drug in your system.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between nirmatrelvir/ritonavir and tadalafil - always consult your physician or pharmacist first.

Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.