# ED Medication Dosage Guide

> Standard doses, timing, food effects and adjustment rules for all four PDE5 inhibitors — plus the most common dosing mistakes and how to avoid them.

- **Source:** ED Treatment Guides (https://www.edtreatmentguides.com/guides/dosage-guide)
- **Last updated:** 2025-11-18
- **Type:** guide
- **Topic:** Safety & medication

## Key points

- All four medications are taken a maximum of once in 24 hours, with the exception of low-dose daily tadalafil.
- Start low, and increase only with your prescriber's agreement after a genuine trial.
- A high-fat meal delays sildenafil and vardenafil significantly. Tadalafil and avanafil are less affected.
- Give any dose four to eight proper attempts before deciding it does not work.
- Never adjust a dose yourself by splitting, doubling or combining tablets.

## Standard dosing at a glance

**Adult dosing for erectile dysfunction**

| Medication | Available doses | Usual start | Take before sex | Max frequency |
| --- | --- | --- | --- | --- |
| Sildenafil | 25, 50, 100 mg | 50 mg | 30–60 minutes | Once in 24 hours |
| Tadalafil (on demand) | 5, 10, 20 mg | 10 mg | At least 30 minutes | Once in 24 hours |
| Tadalafil (daily) | 2.5, 5 mg | 2.5–5 mg | Same time each day | Once daily, continuous |
| Vardenafil | 2.5, 5, 10, 20 mg | 10 mg | About 60 minutes | Once in 24 hours |
| Vardenafil ODT | 10 mg only | 10 mg | About 60 minutes | Once in 24 hours |
| Avanafil | 50, 100, 200 mg | 100 mg | 15–30 minutes | Once in 24 hours |

_This is general reference information. Your prescriber's instruction always takes precedence, and doses are reduced for older age, liver or kidney impairment, and interacting medications._

## Timing and food

| Medication | Food effect | Practical advice |
| --- | --- | --- |
| Sildenafil | Significant — a high-fat meal can delay onset by an hour or more | Take on a relatively empty stomach, or allow extra time |
| Vardenafil | Significant | Same approach as sildenafil |
| Tadalafil | Minimal | Can be taken with food |
| Avanafil | Modest | A very heavy meal will still slow it somewhat |

> **The dinner-date problem**
>
> A common failure pattern: take sildenafil before a large restaurant meal with wine, then find it has not worked by the time you get home. Take it earlier, keep the meal lighter, or use tadalafil, which is far less sensitive to food.

## Adjusting the dose properly

1. **Give the starting dose a genuine trial** — four to eight separate attempts, taken correctly, with actual sexual stimulation.
2. **If the response is partial**, ask your prescriber about increasing to the next dose.
3. **If there is no response at all** at the maximum tolerated dose after a proper trial, switching molecules is the standard next step.
4. **If side effects are the problem**, a lower dose often keeps the benefit. Failing that, switch — see [side effects](https://www.edtreatmentguides.com/guides/side-effects).
5. **If two different molecules fail**, that is the point to ask about urology referral and second-line options.

> **Never do these**
>
> Do not take more than one dose in 24 hours. Do not combine two different ED medications. Do not split or double tablets without instruction. Do not use someone else's prescription. Each of these raises the risk of hypotension and priapism.

## The most common dosing mistakes

- **Expecting it to work without arousal.** These drugs amplify a signal; they do not create one.
- **Not allowing enough time.** Sildenafil needs 30–60 minutes, longer after food.
- **Judging it on one attempt.** First-time anxiety is near-universal and resolves with repetition.
- **Drinking heavily with it.** Alcohol impairs erections independently and compounds side effects.
- **Escalating the dose without asking.** Higher doses raise side effects faster than they raise efficacy.
- **Stopping too soon after a partial response.** A partial response is a signal to adjust, not to give up.

## Frequently asked questions

### Can I take two tablets if one does not work?

No. Exceeding the maximum dose increases side effects and risks without improving results. Speak to your prescriber about a dose increase instead.

### How long before sex should I take it?

Sildenafil and vardenafil 30–60 minutes; tadalafil at least 30 minutes and often longer; avanafil 15–30 minutes. Allow extra time after a heavy meal.

### Can I take ED medication every day?

Only tadalafil is licensed for daily use, at 2.5 or 5 mg. The others are for use as needed, once in 24 hours.

### Does the dose need to change as I get older?

Lower starting doses are standard over 65 and with liver or kidney impairment. Your requirement may also change as other conditions or medications change.

### Can I split tablets to save money?

Only if your prescriber and pharmacist have told you a particular tablet can be split safely. Some are not scored or not evenly distributed, and splitting them gives an unreliable dose.

## Sources

- U.S. Food and Drug Administration. [Drugs@FDA — approved drug products and prescribing information](https://www.accessdata.fda.gov/scripts/cder/daf/)
- American Urological Association. [Erectile Dysfunction: AUA Guideline](https://www.auanet.org/guidelines-and-quality/guidelines/erectile-dysfunction-(ed)-guideline) (2018)
- MedlinePlus (National Library of Medicine). [Drugs, Herbs and Supplements](https://medlineplus.gov/druginformation.html)

## Related pages

- [PDE5 Inhibitor Safety: Interactions, Contraindications and Emergencies](https://www.edtreatmentguides.com/guides/pde5-safety)
- [ED Medication Side Effects, Explained and Managed](https://www.edtreatmentguides.com/guides/side-effects)
- [Sildenafil (Viagra): How It Works, Dosing, Cost and Side Effects](https://www.edtreatmentguides.com/treatments/sildenafil)
- [Treatment cost calculator](https://www.edtreatmentguides.com/tools/cost-calculator)

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_This page is general health information, not medical advice. It cannot account for your own history, medications or risk factors. Talk to a licensed clinician before starting, stopping or changing any treatment._

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