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Penegra: Uses, Dosage & Safety Information

Penegra

Penegra

Penegra

Sildenafil citrate
Penegra is an unapproved sildenafil tablet attributed to Zydus. Many men who use it also take an alpha-blocker for the prostate, and approved labelling then requires stable alpha-blocker treatment first and a 25 mg sildenafil starting dose. Sildenafil must never be combined with nitrates.
  • ActiveIngredient: Sildenafil citrate
  • DosageForm: Oral tablet
  • Dosage: 25 mg, 50 mg, 100 mg
  • Indications: Erectile dysfunction
  • Manufacturer: Zydus Healthcare Ltd
  • Storage: Store below 30°C
  • Drug Status: Not Approved
Drug Status: Not Approved
Description

What is Penegra?

Men who need this drug are often already taking a prostate medicine, and that changes the dose. Where an alpha-blocker such as tamsulosin or doxazosin is in use, approved sildenafil labelling directs that the patient be stable on it first and that sildenafil be started at the lowest approved dose — a quarter of the strength this brand is usually sold in.

Two drugs that lower blood pressure, prescribed to the same men
Alpha-blockers relax smooth muscle in the prostate and bladder neck; they also relax it in blood vessels. Sildenafil lowers blood pressure through a different mechanism. Combined without care, the result is symptomatic hypotension.
The approved instruction has two parts, and both are easy to lose outside a prescription: be established on the alpha-blocker before adding sildenafil, and begin sildenafil at the lowest approved dose rather than the usual 50.1

Penegra is attributed to Zydus and sold as sildenafil citrate in several strengths.25

No product under this name holds FDA approval.3 The molecule is covered under approved sildenafil; the prostate medicine most often involved is described under tamsulosin.

Listed under erectile dysfunction.

General Instructions

How to Take Penegra

How approved sildenafil is taken

For most men approved sildenafil starts at 50 mg, but with an alpha-blocker the starting dose is 25 mg, taken no more than once a day.1

If you take a prostate medicine, say so before any erectile treatment is chosen. It changes both the dose and the sequence.

Do not start both in the same week. The labelling expects the alpha-blocker to be established first.

Stand up slowly for the first few doses, and sit or lie down if you feel light-headed.

If you have both problems, ask about tadalafil — it is approved for erectile dysfunction, for prostate symptoms and for the two together.

Nitrates remain an absolute bar, and men with cardiac disease often take both a nitrate and an alpha-blocker.

If you take an alpha-blocker

Be stable on the alpha-blocker before adding sildenafil, and begin at 25 mg, the lowest approved dose, as the approved labelling directs.1

Side Effects

What Are the Side Effects of Penegra?

No profile exists for this brand. The table shows sildenafil’s documented reactions with the ones an alpha-blocker amplifies marked, since that combination is the subject of this page.

Reactions and the Effect of
ReactionAmplified by an alpha-blocker?
Dizziness on standingYes — the principal concern
FaintingYes
HeadacheSomewhat, through vasodilation
FlushingSomewhat
Nasal congestionYes — both classes cause it
Visual disturbanceNo — related to sildenafil exposure alone

Source: 1

The first two rows are what symptomatic hypotension looks like from the inside, and in an older man a faint is not a minor event: it is a fall.

Emergency – seek care
  • Fainting or a fall — particularly if a prostate medicine is also being taken
  • Chest pain during or after sex — say what you took and when
  • Sudden loss of vision in one or both eyes, or sudden hearing loss
  • An erection lasting more than four hours
Uses

What is Penegra Used For?

No approved use under this brand. What this page adds is the interaction that applies to a large share of the men who want the drug, because prostate symptoms and erectile difficulty rise together with age.3

The overlap, and what each class does about it

The middle rows are the practical finding. A man with both problems has an approved option that treats both, and it is not sildenafil. Tadalafil holds indications for erectile dysfunction, for benign prostatic hyperplasia, and for the two together; sildenafil holds only the first.

Why the reduced-dose instruction exists

Alpha-blockers were developed as blood-pressure drugs before they were used for the prostate, and the effect never went away. Adding a second vasodilator to a man already taking one is the situation in which dizziness on standing, and occasionally collapse, occurs. The labelling handles it by sequencing — establish one, then add the other — and by halving the usual starting dose.1

What a single-strength supply removes

Both halves of the instruction require someone to know that an alpha-blocker is in use. Nothing about obtaining a box of maximum-strength tablets surfaces that question, and the reduced starting dose is unavailable to anyone who obtained the wrong strength in bulk.

The approved route for a man with both conditions is a consultation that names them both, and tadalafil is where that conversation usually leads.

Safety Advice

Interactions Alcohol:

Unsafe
Alcohol adds to the blood-pressure lowering of sildenafil, and the effect compounds further where an alpha-blocker is also being taken.

Interactions Other Medications:

Unsafe
Alpha-blockers such as tamsulosin and doxazosin require that the patient be established on them first and that sildenafil start at 25 mg. Nitrates and guanylate cyclase stimulators are absolute contraindications, and ritonavir or a strong CYP3A4 inhibitor also caps the dose at 25 mg.

Special Groups Pregnancy:

Unsafe
Not applicable — sildenafil has no approved use in women for this indication.

Special Groups Breastfeeding:

Unsafe
Not applicable to the stated indication.

Special Groups Elderly:

Unsafe
The labelled starting dose over 65 is 25 mg, and this is the age group most likely to be taking a prostate medicine — a second reason for the same reduction, and a fall is a serious event at that age.

Special Groups Children:

Unsafe
Not indicated for this purpose under 18.

Effects on Activities Driving:

Unsafe
Dizziness on standing is the principal concern where an alpha-blocker is also in use. Do not drive until the effect of a dose is known.

Effects on Activities Operating Machinery:

Unsafe
The same applies, for the same reason.
Concerns

Penegra is sildenafil citrate attributed to Zydus, sold at 25, 50 and 100 mg. Nothing under this name is registered with the FDA.23

The specific risk here is not exotic. Erectile difficulty and prostate symptoms arrive in the same men at roughly the same age, and the standard treatment for the second is a drug that lowers blood pressure. Approved labelling handles the combination carefully: establish one, then add the other at half the usual starting dose.

Neither half of that instruction survives supply without a conversation. Nobody asks whether an alpha-blocker is in use, and the reduced dose is unavailable to a man who obtained a box of one strength.

There is also a better answer available to exactly this man. Tadalafil is approved for erectile dysfunction, for benign prostatic hyperplasia, and for both at once — one prescription for two problems that are usually raised in the same appointment, if the appointment happens.

Warnings

Critical Warnings for Penegra Use

An alpha-blocker changes the starting dose to 25 mg

And requires that the alpha-blocker be established first. Both instructions depend on someone knowing it is being taken.

Prostate symptoms and erectile difficulty overlap by age

A large share of men seeking this drug are in the group for whom the reduced dose applies.

Sildenafil is not approved for prostate symptoms

Tadalafil is, including for both conditions together; sildenafil holds only the erectile indication.

Nitrates

Sildenafil is contraindicated with nitric oxide donors such as organic nitrates or nitrites in any form.1

Guanylate cyclase stimulators

Sildenafil is contraindicated with guanylate cyclase stimulators such as riociguat.1

Sildenafil hypersensitivity

Contraindicated in known hypersensitivity to sildenafil or any tablet component.1

No approval exists under this name

And no route by which the 25 mg instruction would be raised at the point of sale.

Source: 143

See Interactions.

Dosage

Dosage

The starting dose depends on a question about the prostate
Approved sildenafil starts at 50 mg for most men and at 25 mg where an alpha-blocker is being taken — alongside the same 25 mg reduction for age over 65, hepatic impairment, severe renal impairment and strong CYP3A4 inhibitors.1
When the Approved Starting Dose Is
SituationHow common in men seeking this drug
Taking an alpha-blocker for prostate symptomsCommon — both conditions rise with age
Over 65Common
Hepatic impairmentOccasional, often unrecognised
Severe renal impairmentOccasional
Strong CYP3A4 inhibitorOccasional, depends on other prescriptions

Source: 1

▶Clinical detailstechnical detail

The sequencing instruction — be stable on the alpha-blocker first — matters more than it appears. Alpha-blocker therapy itself causes a fall in blood pressure that settles over the first days to weeks as the circulation adapts. Adding a second vasodilator during that window means two unadapted effects arriving together, which is precisely the pattern the labelling is written to avoid.

Interaction studies were run in men with benign prostatic hyperplasia taking doxazosin, after at least fourteen consecutive daily doses, which is the practical definition of established therapy. A man who starts a prostate medicine and an erectile medicine in the same week has not reproduced those conditions, and the results from them do not describe his situation.1

Interactions

What Does Penegra Interact With?

The alpha-blocker row is the one most men in this group need to read first.

Interactions by Severity
Interacting SubstanceEffect and RiskSeverityDocumentation
Organic nitrates or nitrites in any formDangerous fall in blood pressureContraindicatedExcellent — labelled contraindication
Guanylate cyclase stimulators such as riociguatLow blood pressureContraindicatedExcellent — labelled contraindication
RitonavirMuch higher sildenafil exposure; no more than 25 mg in 48 hoursMajorExcellent — labelled interaction
Strong CYP3A4 inhibitors such as ketoconazole, itraconazole, erythromycinHigher exposure; a 25 mg starting dose consideredMajorGood — labelled interaction
Alpha-blockers and other blood pressure medicinesAdditive fall in blood pressure; start at 25 mg with alpha-blockersModerateGood — labelled interaction

Source: 1

FAQs
Yes, in two ways. The approved labelling says you should be stable on the alpha-blocker before sildenafil is started, and that sildenafil should begin at 25 mg rather than the usual 50.
Alpha-blockers relax smooth muscle in the prostate and bladder neck, and also in blood vessels — they began as blood-pressure drugs. Sildenafil lowers blood pressure by a different route. Together they can cause dizziness on standing or fainting.
The interaction studies used men who had taken doxazosin for at least fourteen consecutive days. Starting a prostate medicine and an erectile medicine in the same week does not reproduce those conditions.
Tadalafil is approved for erectile dysfunction, for benign prostatic hyperplasia, and for the two together. Sildenafil holds only the erectile indication.
A halved 100 mg tablet is 50 mg, not 25. Reaching the labelled starting dose in this situation requires the 25 mg strength, which is why it exists.
Evidence and Reported Data

Evidence Scope

Established
  • Where an alpha-blocker is being taken, approved labelling directs that the patient be stable on it before sildenafil is started, and that sildenafil begin at 25 mg.1
  • The interaction studies were conducted in men with benign prostatic hyperplasia taking doxazosin after at least fourteen consecutive daily doses.1
  • Tadalafil is approved for erectile dysfunction, for benign prostatic hyperplasia, and for the two conditions together; sildenafil is approved only for the first.4
  • Nothing under this brand name appears in any FDA record.
Unknown, and why
  • How many users are on an alpha-blocker. Unknown because the supply route records no medicine list, and prostate treatment is not something men volunteer when obtaining an erectile drug.
  • What a tablet under this name contains. Unknown; no registered specification exists.
  • Whether falls have followed the combination in this population. Unknown: a fall in an older man is investigated as a fall, and the tablet taken the previous evening rarely enters the account.

FDA adverse event reports

No reports are filed under the name Penegra at the 2026-07-30 data cut; cases involving sildenafil are recorded under the molecule or an approved brand, and a count of reports is not a rate.3

Who was this medicine studied in?

No one, under this brand. The alpha-blocker data come from interaction studies in men with benign prostatic hyperplasia established on doxazosin, and the efficacy data from men with erectile dysfunction in the approval programme.1

Who this is and is not appropriate for

No one, on the available evidence, and least of all a man taking tamsulosin or another alpha-blocker, for whom the labelling requires both a sequence and a reduced dose that this supply route cannot supply.1

Where both erectile difficulty and prostate symptoms are present, tadalafil holds an approved indication covering both.

Dose Figures Behind This Page

PDE5 Inhibitors
QuestionSildenafilTadalafil
Approved for erectile dysfunctionYesYes
Approved for benign prostatic hyperplasiaNoYes
Approved for both togetherNoYes, as a single indication
With an alpha-blockerBe stable on it first; start sildenafil at 25 mgBe stable on it first; start at the lowest labelled dose

Source: 14

Where to report and verify

Routing to Official Registries
What you needWhere to go
Report a side effectFDA MedWatch
Pregnancy-specific dataMotherToBaby
Full prescribing informationDailyMed
Verify a pharmacy websiteFDA BeSafeRx · LegitScript
References

References

  1. FDA Prescribing Information, VIAGRA (sildenafil citrate) — Sections 2.1–2.4 Dosage and Administration, 4.1 Contraindications, 5.5 Alpha-Blockers and Other Antihypertensives, 6 Adverse Reactions, 7.2 Drug Interactions, 12.2 Clinical Pharmacology, 14 Clinical Studies
    Revised 2025-08 · Accessed 2026-09-23
    Used for: the instruction to be stable on alpha-blocker therapy before starting sildenafil and to initiate at 25 mg, the doxazosin interaction studies in men with benign prostatic hyperplasia after fourteen daily doses, the other 25 mg reductions, the nitrate contraindication and the adverse reactions.
    dailymed.nlm.nih.gov — VIAGRA SPL
  2. Vendor and manufacturer product listings for Penegra
    Commercial listings, not regulatory records · Accessed 2026-09-23
    Used for: the manufacturer attribution to Zydus and the strengths of 25, 50 and 100 mg. Reproduced as claims.
  3. openFDA — Drugs@FDA, labelling, NDC Directory and FAERS queries for this brand
    Data cut 2026-07-30 · Accessed 2026-09-23
    Used for: the absence of any application, product code, labelling or adverse event record under this brand name.
    open.fda.gov — drug adverse event API
  4. FDA Prescribing Information, CIALIS (tadalafil) — Sections 1.1–1.4 Indications and 7.1 Drug Interactions
    Revised 2026-06 · Accessed 2026-09-23
    Used for: the approved indications for erectile dysfunction, for benign prostatic hyperplasia and for the two together, and the corresponding alpha-blocker instruction.
    dailymed.nlm.nih.gov — CIALIS SPL
  5. FDA National Drug Code Directory — sildenafil products by strength
    Directory accessed 2026-09-23
    Used for: the registered strengths, including the 25 mg tablet that the alpha-blocker instruction depends on.
    accessdata.fda.gov — NDC Directory

How this page was sourced

Both approved labellings are cited because the comparison between the two molecules is the useful part: one treats both conditions, the other does not, and a reader with both should be able to check that directly.

The doxazosin study conditions are quoted, including the fourteen days of prior dosing, because the sequencing instruction only means something against that detail.

No estimate is offered of how many users take an alpha-blocker, since no source establishes it.

Review cycle. Clinical review completed 28 September 2026. Next review due by 28 September 2027, or earlier if the labelling is revised.

Disclaimer

Disclaimer: The information on this site is provided for informational purposes only and is not medical advice. It does not replace professional medical consultation, diagnosis, or treatment. Do not self-medicate based on the information presented on this site. Always consult with a doctor or other qualified healthcare professional before making any decisions about your health.