What is the difference between generic sildenafil and brand-name Viagra?

Is generic sildenafil the same as Viagra? In every way that matters to how it works, yes. Both contain the same medicine, sildenafil, and in Australia a generic is only allowed to be supplied if the TGA considers that it is bioequivalent to the original: the same dose puts the same amount of medicine into your body over the same time (TGA). What can differ is the name, the look of the tablet, the fillers and the price (healthdirect).

What makes a sildenafil tablet "generic"?

Being another brand of the same medicine. Viagra is the original brand of sildenafil; a generic medicine is "an additional brand of an existing medicine", with the same active ingredient, and other companies can make it once the original patent has expired (TGA). The Australian Register of Therapeutic Goods lists 78 sildenafil products (ARTG): Viagra 25, 50 and 100 mg, and generic tablets such as ARX-Sildenafil, Sildenafil Lupin, Sildenafil GH and Noumed Sildenafil, along with sublingual wafers and other forms. Tadalafil has generic brands too: on the PBS, whose tadalafil listing is for veterans only, Cialis sits alongside brands such as Apo-Tadalafil and Tadalafil Sandoz (PBS). More in are there generic drugs for erectile dysfunction?

What does "bioequivalent" mean?

That your body gets the same dose the same way. In the TGA's words, "if you take the same dose of a generic medicine as an existing medicine, the same amount of active ingredient is absorbed by your body over the same period of time". It is shown in a study in which volunteers, usually healthy, take the original on one day and the generic on another, and blood samples compare "the rate and extent of absorption" (TGA).

Before approving a generic, the TGA also checks the manufacturing process, the quality of the ingredients and the finished tablet, and how long the medicine stays stable, which sets its shelf life and storage conditions (TGA). Why a tablet past that date may not work as it should is covered in does expired Cialis still work?

Does generic sildenafil work as well as Viagra?

Yes. "All medicines will have the same potential health benefits, and the same potential side effects", and a medicine that does not work for you will not work better under another brand: "Some active ingredients are only effective for some patients and this will be the case whether you use the original or a generic medicine" (TGA). Generic medicines "contain the same amount of active ingredient that acts in the same way" (healthdirect).

The same directions apply whatever the name: usually 50 mg about one hour before sex, adjusted between 25 mg and 100 mg, no more than once a day, and only with sexual stimulation (EMA). The side effects are the same too, headache, flushing, a blocked nose and indigestion among the common ones, and neither may be taken with nitrates (healthdirect — ED medicines).

So what is different?

The tablet and the pack. Generics may differ in colour, shape, size, taste and packaging, often because of trademark regulations, and can use different fillers and colours, which must meet the same quality and safety standards (healthdirect). Viagra, for example, is a blue, rounded diamond-shaped tablet marked "VGR" and "VIAGRA", and it contains lactose (Viagra CMI). If you have an allergy, tell your doctor or pharmacist, "just in case the generic medicine contains the substances you are allergic to in the inactive ingredients" (TGA). The label calls the medicine "sildenafil (as citrate)" (Viagra CMI); the salt is explained in sildenafil vs sildenafil citrate.

The price usually differs as well. Generic medicines are often cheaper, because their makers have not paid for the medicine's discovery, development and marketing (healthdirect); the TGA does not weigh price when it approves a medicine. How generic Viagra and Cialis compare on price and supply is in generic Viagra and Cialis: price and availability.

Can you choose between generic sildenafil and Viagra?

Usually, yes. Sildenafil is prescription-only in Australia, and a doctor assesses you first (healthdirect — ED medicines). Prescriptions must name the active ingredient, so yours will say sildenafil; "It's usually your choice whether to buy a brand-name medicine or a generic version", though sometimes your doctor will prescribe a specific brand (healthdirect). The TGA puts it plainly: "you do not have to accept any medicine if it is offered to you; the choice is yours".

Is Kamagra a generic Viagra?

Not in the Australian sense. A generic here is a registered brand that the TGA has judged bioequivalent; Kamagra contains sildenafil but has no entry on the ARTG, and products that are not on it "are not approved for supply in Australia, have not been reviewed for safety or quality" (TGA, February 2024). The difference is set out in Kamagra vs Viagra. "Viagra Professional" is not among the three Viagra products on the register either: Viagra vs Viagra Professional.

The short answer

A generic sildenafil approved in Australia is Viagra's medicine under another name, tested to deliver the same dose the same way. It may look different, use different fillers and sell for less; it works the same and carries the same warnings. Other medicines are set side by side in our comparisons of ED medicines.