Sildenafil citrate tablets IP 100 mg: use, dose and limits
Sildenafil citrate tablets IP 100 mg contain a phosphodiesterase type 5 (PDE5) inhibitor approved for erectile dysfunction in adult men. On the reference US label, most men start at 50 mg taken about 1 hour before sexual activity. 100 mg is the highest single dose, and no more than one dose should be taken in 24 hours.[1] In India, sildenafil citrate is a Schedule H drug, so it can be sold only against a registered medical practitioner’s prescription.[2] It must never be taken with nitrates or riociguat.[1] The 100 mg tablet is not the dose used for pulmonary arterial hypertension, which is 5 mg or 20 mg three times a day.[4]
- Drug classPDE5 inhibitor
- India statusRx · Schedule H
- Maximum (ED)100 mg, once in 24 h
- Half-lifeAbout 4 hours
- Not indicatedWomen, children
L-Force-100 tablet: product details
- Brand
- L-Force-100 (printed on the pack as “L-FORCE Tablet”)
- Composition
- Each film-coated tablet contains Sildenafil Citrate IP equivalent to Sildenafil 100 mg
- Dosage form
- Red film-coated tablet for oral use
- Pack
- 1 × 4 blister in a mono carton; 10 mono cartons per shipper (10 × 1 × 4)
- MRP
- ₹128.00 per strip of 4 tablets (₹32.00 per tablet)
- Legal status
- Rx · Schedule H, Drugs Rules 1945[2]
- Price control
- Non-scheduled formulation. Sildenafil is not in NLEM 2022, so no NPPA ceiling price applies, and the MRP may rise by no more than 10% in any 12 months[7][8]
- Storage
- Store below 30°C (follow the strip)
- Marketed by
- Laafon Galaxy Pharmaceuticals, Karnal, Haryana
- Manufactured at
- A third-party WHO-GMP certified unit under contract. The manufacturer’s name and licence number are printed on the strip and carton
Checking a strip that says “Force”? Many unrelated brands use “Force” in their names. A strip is L-Force-100 only if it reads Sildenafil Citrate Tablets IP 100 mg and names Laafon Galaxy Pharmaceuticals. L-Force-100 comes only in 100 mg, so a 25 mg or 50 mg dose needs a lower-strength product.
How sildenafil works (mechanism of action)
During sexual stimulation, nerves and blood-vessel lining in the penis release nitric oxide. Nitric oxide switches on guanylate cyclase, which raises cyclic guanosine monophosphate (cGMP). cGMP relaxes the smooth muscle of the corpus cavernosum, so blood can flow in and produce an erection. PDE5 is the enzyme that breaks cGMP down. Sildenafil blocks PDE5, so cGMP lasts longer.[1]
Two consequences matter in practice. Without sexual stimulation, sildenafil has no effect. And because nitrates also act through the nitric oxide–cGMP pathway, taking the two together can cause a dangerous fall in blood pressure. That is why the combination is contraindicated.[1] The main metabolite, N-desmethyl sildenafil, has about 50% of the parent drug’s PDE5 potency and accounts for about 20% of its effect.[1]
Sildenafil citrate tablets 100 mg uses: approved and not approved
The reference label approves the 25, 50 and 100 mg tablets for one use only: erectile dysfunction in men.[1] Sildenafil is also used for pulmonary arterial hypertension, but that is a different product at a much lower dose, so this 100 mg tablet should not be used for it.
| Use | Status | Dose used | What it means for a 100 mg tablet |
|---|---|---|---|
| Erectile dysfunction, adult men | Approved | 25–100 mg as needed, at most once a day[1] | This is the use the 100 mg strength exists for |
| Pulmonary arterial hypertension (WHO Group I), adults | Approved, separate product | 5 mg or 20 mg three times a day, 4–6 hours apart. Doses above 20 mg three times a day are not recommended[4] | Not a use for a 100 mg tablet. A PAH product should not be combined with another PDE5 inhibitor[4] |
| Secondary Raynaud’s phenomenon | Studied, not approved | 50 mg twice daily for 4 weeks in a 16-patient crossover trial[5] | Fewer and shorter attacks than placebo in a small study. This is off-label, specialist territory |
| Women | Not indicated | — | The label states it is not indicated for use in females[1] |
| Children | Not indicated | — | The label states it is not indicated for use in paediatric patients[1] |
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Sildenafil 100 mg dosage and timing
- Usual starting dose: 50 mg, taken as needed about 1 hour before sexual activity. It can be taken anywhere from 30 minutes to 4 hours beforehand.[1]
- Range: 25–100 mg, adjusted to effect and tolerability. The maximum is 100 mg, once a day.[1]
- Food: it can be taken with or without food. A high-fat meal delays the peak by about 60 minutes and lowers peak concentration by about 29%.[1]
- On starting at 100 mg: in a 2009 randomised trial, men who started on 100 mg had no more adverse events than men who started on 50 mg, and they reported higher treatment satisfaction.[6] The label still recommends 50 mg as the starting dose for most men. The doctor decides the strength.
Label starting-dose check (for prescribers and pharmacists)
Answer the three rows to see which rule from the reference label applies. This summarises the label. It does not replace a prescriber’s judgement.
1. Is the patient taking any nitrate or nitric oxide donor (e.g. nitroglycerin, isosorbide), or riociguat?
2. Is the patient taking ritonavir?
3. Does any of these apply?
Answer all three rows
The rule from the reference label will appear here.
Source: VIAGRA US prescribing information, sections 2 and 4 [1]
Who should not take sildenafil, and who needs caution
Contraindicated
- Any nitrate or nitric oxide donor, taken regularly or occasionally. The label says it is not known when a nitrate can safely be given after sildenafil.[1] This includes nitrite “poppers”.[3]
- Guanylate cyclase stimulators such as riociguat.[1]
- Known hypersensitivity to sildenafil or any tablet component.[1]
Not studied: prescribe only with caution
- Heart attack, stroke or life-threatening arrhythmia within the last 6 months.[1]
- Resting blood pressure below 90/50 mmHg or above 170/110 mmHg.[1]
- Cardiac failure, or coronary artery disease causing unstable angina.[1]
- Left ventricular outflow obstruction, e.g. aortic stenosis.[1]
- Retinitis pigmentosa, a previous NAION or a “crowded” optic disc.[1]
- Bleeding disorders or active peptic ulceration.[1]
Side effects of sildenafil citrate tablets
The figures below are from the label’s flexible-dose trials (sildenafil 25–100 mg, n = 734, against placebo, n = 725). They list the reactions reported by at least 2% of treated men and more often than on placebo.[1]
| Adverse reaction | Sildenafil | Placebo |
|---|---|---|
| Headache | 16% | 4% |
| Flushing | 10% | 1% |
| Dyspepsia (indigestion) | 7% | 2% |
| Nasal congestion | 4% | 2% |
| Abnormal vision (mostly a brief colour tinge, light sensitivity or blur) | 3% | 0% |
| Back pain | 2% | 2% |
| Dizziness | 2% | 1% |
| Rash | 2% | 1% |
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Get medical help straight away for
- An erection lasting more than 4 hours. Priapism, a painful erection lasting more than 6 hours, needs emergency treatment.[1]
- Sudden loss of vision in one or both eyes (possible NAION).[1]
- A sudden drop in or loss of hearing, sometimes with ringing in the ears or dizziness.[1][3]
- Chest pain, fainting or worsening breathlessness.[3]
Sildenafil gives no protection against sexually transmitted infections and does not prevent pregnancy.[1][3]
Sildenafil drug interactions
Sildenafil is cleared mainly by CYP3A4, with a minor contribution from CYP2C9. Drugs that block CYP3A4 therefore raise its blood levels.[1]
| Interacting drug | Effect | Label action |
|---|---|---|
| Nitrates or nitric oxide donors, any form | Large additive fall in blood pressure | Contraindicated |
| Riociguat and other guanylate cyclase stimulators | Additive hypotension | Contraindicated |
| Ritonavir | Sildenafil exposure up about 11-fold | 25 mg, no more than once in 48 hours |
| Saquinavir | Cmax up 140%, AUC up 210% | Consider a 25 mg starting dose |
| Erythromycin | Cmax up 160%, AUC up 182% | Consider a 25 mg starting dose |
| Ketoconazole, itraconazole (strong CYP3A4 inhibitors) | Exposure expected to rise | Consider a 25 mg starting dose |
| Alpha-blockers | Symptomatic low blood pressure possible | Patient stable on the alpha-blocker first; start at 25 mg |
| Cimetidine 800 mg | Plasma sildenafil up 56% | Be aware; no specific dose rule |
| Alcohol | Sildenafil did not add to alcohol’s blood-pressure effect in healthy volunteers | No label dose change |
| Other PDE5 inhibitors, including sildenafil for PAH | Same pathway, so effects add up | Combination not recommended |
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All figures in this table come from the VIAGRA label, sections 2, 4, 5 and 7.[1] MedlinePlus also lists St John’s wort as an interacting product and advises asking a doctor about grapefruit.[3]
Pharmacokinetics at a glance
| Parameter | Value (reference label) |
|---|---|
| Absolute oral bioavailability | 41% (range 25–63%) |
| Time to peak, fasting | 30–120 minutes (median 60) |
| Effect of a high-fat meal | Peak about 60 minutes later; Cmax down about 29% |
| Plasma protein binding | About 96% (parent and metabolite) |
| Metabolism | CYP3A4 (major), CYP2C9 (minor); active N-desmethyl metabolite |
| Terminal half-life | About 4 hours |
| Excretion | About 80% in faeces, about 13% in urine |
Source: VIAGRA US prescribing information, section 12.3.[1]
Sildenafil in Indian regulation: schedule, price and advertising
Schedule H, not H1 or X
Sildenafil citrate is entry 453 of Schedule H in CDSCO’s consolidated Drugs and Cosmetics Rules, 1945. It does not appear in Schedule H1 or Schedule X.[2] That means it may be sold by retail only on a registered medical practitioner’s prescription, and the strip must carry the Schedule H caution.[2] Our Schedule H drugs list and labelling rules covers the caution wording. Schedule H1 is amended by gazette notification from time to time, so check the current Schedule H1 drug list rather than relying on any single year’s list.
No NPPA ceiling price
Sildenafil is not in the National List of Essential Medicines 2022.[7] Under DPCO 2013 (S.O. 1221(E), 15 May 2013), only formulations in the First Schedule get a ceiling price. Sildenafil tablets are therefore non-scheduled formulations, and paragraph 20 limits any MRP increase to 10% in the preceding 12 months.[8] Current ceiling prices for scheduled drugs are in our NPPA DPCO 2026 drug price list.
Why this page makes no promotional claims
Section 3(b) of the Drugs and Magic Remedies (Objectionable Advertisements) Act, 1954 bans advertisements suggesting that a drug maintains or improves capacity for sexual pleasure. Its Schedule lists “sexual impotence” among the conditions a drug may not be advertised to treat. Section 14 exempts treatises written from a bona fide scientific or social standpoint.[9] Separately, Rule 106 and Schedule J of the Drugs Rules, 1945 bar a drug from claiming to cure “sexual impotence, premature ejaculation and spermatorrhoea”.[2] This page therefore sticks to label facts. Sildenafil products should not be promoted to the public with performance claims.
Sildenafil brands in India
Sildenafil is a crowded generic. In October 2026, 1mg listed 182 substitutes for a single sildenafil 50 mg brand.[10] Every brand contains the same active ingredient; strengths, packs, excipients and prices differ. Some widely listed brands:
| Brand | Company listed | Details |
|---|---|---|
| Viagra | Mylan Pharmaceuticals Pvt Ltd (a Viatris company) | Originator brand |
| Manforce | Mankind Pharma Ltd | — |
| Penegra | Zydus Cadila | — |
| Suhagra | Cipla Ltd | — |
| Caverta | Sun Pharmaceutical Industries Ltd | — |
| L-Force-100 | Laafon Galaxy Pharmaceuticals | View L-Force-100 product details |
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Company names for the other brands are taken from the 1mg substitutes listing,[10] which is a marketplace source and not a regulatory one.
Distributors and brand owners: licence requirements, pack options and compliance limits are on our sildenafil citrate tablets PCD franchise and third-party manufacturing page.
Frequently asked questions
For erectile dysfunction, the label sets sildenafil as an as-needed medicine: no more than one dose in 24 hours, and no more than 100 mg per dose. Whether a patient should use it often, and at what strength, is the prescriber’s decision. The three-times-daily schedule used in pulmonary arterial hypertension applies to a separate 5 mg or 20 mg product, not to a 100 mg tablet.
About 1 hour before, although the label allows anywhere from 30 minutes to 4 hours. Blood levels usually peak in 30 to 120 minutes on an empty stomach, and a high-fat meal can delay this by about an hour. Sildenafil works only with sexual stimulation.
Both contain sildenafil 100 mg as sildenafil citrate. Viagra is the originator brand. L-Force-100 is a generic brand marketed by Laafon Galaxy Pharmaceuticals and made at a third-party WHO-GMP certified unit. The tablet colour, excipients, pack and price differ between brands, and either one needs a prescription.
No. The reference label states that sildenafil tablets for erectile dysfunction are not indicated for use in females. Women with pulmonary arterial hypertension may be treated with sildenafil, but with a separate PAH product at 5 mg or 20 mg three times a day, under specialist care.
No. The adult PAH dose on the Revatio label is 5 mg or 20 mg three times a day, given 4 to 6 hours apart. Doses higher than 20 mg three times a day are not recommended. A 100 mg tablet cannot provide that dose, and a PAH product should not be combined with another PDE5 inhibitor.
Yes. Sildenafil citrate is entry 453 in Schedule H of the Drugs and Cosmetics Rules, 1945. A chemist may sell it by retail only against a prescription from a registered medical practitioner, and the strip must carry the Schedule H caution.
Get emergency medical help straight away. The label tells patients to seek immediate help for an erection lasting more than 4 hours. Priapism, defined as a painful erection lasting more than 6 hours, needs urgent treatment.
Search engines group brand names that look alike, and many unrelated products use the word Force. Check the composition line on the strip. L-Force-100 reads Sildenafil Citrate Tablets IP 100 mg and names Laafon Galaxy Pharmaceuticals.
Who wrote and reviewed this page
Written by Darshan Singh
M.Sc. Organic Chemistry, D.Pharm. 23+ years in pharmaceutical quality control, quality assurance and drug regulatory affairs.
First published 9 Nov 2024 · Rebuilt 26 Oct 2026 · Facts checked against the cited labels and Rules on 26 Oct 2026
Reviewed by Yogesh Chaudhary, B.Pharm
Registered Pharmacist, Uttar Pradesh State Pharmacy Council. Senior Pharmacist, S.N. Medical College, Agra, with 15+ years in clinical pharmacy and medication management.
Related on Laafon
References
- Pfizer Labs. VIAGRA (sildenafil citrate) tablets, for oral use: full prescribing information. Revised 12/2017. Silver Spring (MD): U.S. Food and Drug Administration; 2017. Available from: https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/020895s048lbl.pdf. Accessed October 2026.
- Ministry of Health and Family Welfare, Government of India. The Drugs and Cosmetics Act, 1940 and the Drugs and Cosmetics Rules, 1945 (as amended up to 31 December 2016): Rule 106; Schedule H, entry 453; Schedule J, entry 47. New Delhi: Central Drugs Standard Control Organisation; 2016. Available from: https://cdsco.gov.in/opencms/export/sites/CDSCO_WEB/Pdf-documents/acts_rules/2016DrugsandCosmeticsAct1940Rules1945.pdf. Accessed October 2026.
- MedlinePlus [Internet]. Bethesda (MD): National Library of Medicine (US); Sildenafil. Last revised 15 August 2023. Available from: https://medlineplus.gov/druginfo/meds/a699015.html. Accessed October 2026.
- Pfizer Labs. REVATIO (sildenafil) tablets, oral suspension and injection: prescribing information. Revised 4/2020. New York: Pfizer Inc; 2020. Available from: https://labeling.pfizer.com/ShowLabeling.aspx?id=645. Accessed October 2026.
- Fries R, Shariat K, von Wilmowsky H, Böhm M. Sildenafil in the treatment of Raynaud’s phenomenon resistant to vasodilatory therapy. Circulation. 2005;112(19):2980-5. doi:10.1161/CIRCULATIONAHA.104.523324. Available from: https://pubmed.ncbi.nlm.nih.gov/16275885/. Accessed October 2026.
- Loran OB, Ströberg P, Lee SW, Park NC, Kim SW, Tseng LJ, et al. Sildenafil citrate 100 mg starting dose in men with erectile dysfunction in an international, double-blind, placebo-controlled study: effect on the sexual experience and reducing feelings of anxiety about the next intercourse attempt. J Sex Med. 2009;6(10):2826-35. doi:10.1111/j.1743-6109.2009.01428.x. Available from: https://pubmed.ncbi.nlm.nih.gov/19817982/. Accessed October 2026.
- Standing National Committee on Medicines. National List of Essential Medicines (NLEM) 2022: report. New Delhi: Ministry of Health and Family Welfare / ICMR; 2022. Available from: https://icmr.gov.in/icmrobject/custom_data/1720338777_report_nlem_2022_f_website.pdf. Accessed October 2026.
- Department of Pharmaceuticals, Government of India. Drugs (Prices Control) Order, 2013. S.O. 1221(E), dated 15.05.2013, paragraphs 2(zb) and 20. Available from: https://pharma-dept.gov.in/sites/default/files/DPCO2013_0.pdf. Accessed October 2026.
- Government of India. The Drugs and Magic Remedies (Objectionable Advertisements) Act, 1954 (Act 21 of 1954), sections 3 and 14 and the Schedule. India Code. Available from: https://www.indiacode.nic.in/indiacode/bitstream/123456789/1412/1/A1954-21.pdf. Accessed October 2026.
- Tata 1mg. Substitutes for Sidegra 50 Tablet (sildenafil 50 mg) [marketplace listing; secondary source]. Available from: https://mars.1mg.com/drugs-substitutes/sidegra-50-tablet-668610. Accessed October 2026.
Disclaimer. This page is technical and educational information on a prescription medicine for healthcare professionals, pharmacists and trade buyers. It is not medical advice, a recommendation to use any product, or legal advice. Sildenafil must be used only as a registered medical practitioner directs. Indian schedules, price notifications and advertising rules change by gazette notification, and the US label is used here as the reference prescribing information. Check the current approved package insert and the latest notifications before acting on any figure.