Sildenafil vs tadalafil: timing, food, daily use, and cost
Compare Viagra and Cialis by the decisions that affect everyday use: dose timing, meals, prescribing schedule, side effects, and the full prescription cost.
Written by The ED Watch Editorial Board
Medical review pending · Source-based editorial draft
Drafted
Sources checked
Sildenafil and tadalafil both treat erectile dysfunction, but they offer different ways to plan treatment. Start the comparison with the problem you want to solve: timing a dose, tolerating side effects, paying for repeat prescriptions, or getting a more reliable response. A longer response window does not by itself make a medicine a better fit.
The practical differences
The comparison below summarizes MedlinePlus's sildenafil information and the Cialis prescribing information. It concerns standard oral ED prescriptions. A compounded chewable, gummy, or combination can have different instructions and should be checked separately.
| Question | Sildenafil / Viagra | Tadalafil / Cialis |
|---|---|---|
| How is it scheduled for ED? | Usually as needed before sexual activity | As needed or on a separate once-daily prescribing schedule |
| What does timing mean? | MedlinePlus describes about an hour before sex, with a permitted window from 30 minutes to four hours before | As-needed labeling describes a potential benefit for up to 36 hours after a dose |
| Does food matter? | A high-fat meal may delay the start of action | Can be taken without regard to food |
| Is stimulation still needed? | Yes | Yes |
| What should be compared on price? | The prescribed strength and quantity, plus service fees | The prescribed daily or as-needed supply, plus service fees |
Choose the question before choosing the product
If the difficulty is planning around a meal, bring that up. If you would prefer to avoid linking a tablet to a particular occasion, ask about daily tadalafil. If medication is used infrequently, compare the cost and practical demands of an as-needed prescription. These preferences help a clinician discuss options; they do not establish that a particular prescription is suitable.
Daily tadalafil uses its own dosing instructions. It is not the same as taking an as-needed tablet every morning. Our guide to daily versus as-needed tadalafil explains that distinction and the questions to ask before switching.
A disappointing response needs context
Tell the prescriber when you took the medicine, whether food was involved, what response occurred, and any side effects. Difficulty getting an erection, losing one, low desire, and ejaculation concerns are different things to describe. The sildenafil follow-up checklist helps turn an unsatisfactory experience into a useful conversation.
Do not compare milligram numbers across drugs as though they were a shared strength scale. A 20 mg tablet of one medicine is not automatically weaker than a 50 mg tablet of another. Also distinguish a tablet's contents from the dose your prescriber tells you to take.
Compare tolerability and interactions with the clinician
Both medicines can cause adverse effects, including headache and indigestion. Report what happened and when; an online ranking cannot predict which symptoms you will experience. Bring your full medication list, including medicines taken only occasionally, and use our side-effect guide to prepare questions.
Put the complete prescription on the same cost basis
Compare the total charge over the same period, including consultation, membership, shipping, and renewal costs. Daily tablets and a small as-needed supply serve different schedules, so a price per pill can be misleading. Use the ED subscription worksheet after the prescription is clear.
For the individual medicines, read our sildenafil review and tadalafil review. If the clinician proposes a different tablet, the vardenafil and avanafil reviews explain their separate labels and practical limits.
Common questions
Is tadalafil stronger than sildenafil?
Milligram strengths cannot be compared directly across these drugs. The useful comparison is the prescribed schedule, response, tolerability, interactions, and cost.
Does tadalafil's 36-hour window mean a 36-hour erection?
No. It describes a period in which response to stimulation may be possible. An erection lasting more than four hours is a medical emergency.
Can I take sildenafil if daily tadalafil did not help?
Do not add it yourself. Contact the prescriber for a review and explicit instructions. Cialis labeling advises against taking it with other PDE5 inhibitors.
Sources
- 1.Sildenafil: patient drug information — MedlinePlus / National Library of Medicine
- 2.Cialis (tadalafil): prescribing information and patient leaflet — DailyMed / National Library of Medicine