When people compare generic vs brand name drugs, the short answer is that they are the same where it counts. A generic medicine contains the same active ingredient as the brand, in the same strength and form, and US generics must be shown to deliver that ingredient into the body at about the same rate and amount. What can differ is the name, the price, the color or shape, and the inactive ingredients that hold the tablet together.

Here is what those differences mean for you, including what to know about generics made in India.

What is the difference between a generic and a brand-name drug?

Every medicine has two kinds of names. The generic name is the name of the active ingredient, the chemical that does the work. The brand name is the trade name a company picks for its own product. As the NHS explains, sildenafil is the generic name, while Viagra is the brand name Pfizer uses for it.

When a company discovers a new medicine, a patent gives it the sole right to sell it for a number of years. Once that protection ends, other companies can make their own versions. Some are sold under the plain generic name, such as sildenafil tablets. Others get a new brand name from their maker. These are often called branded generics, and they are the usual way generics are sold in India.

Is the active ingredient the same?

Yes, and this is the core rule. In the US, the FDA requires a generic to match the brand in active ingredient, strength, dosage form (tablet, capsule, inhaler and so on) and route, meaning how you take it. The generic’s label carries essentially the same uses, dosing and warnings as the brand’s.

So generic tadalafil 20 mg contains the same medicine as Cialis 20 mg, works the same way in the body and should be taken the same way, as prescribed.

Are the inactive ingredients different?

They can be. Inactive ingredients, also called excipients, are the fillers, binders, coatings, colors and flavors that turn a tiny amount of medicine into a tablet you can hold, swallow and store. Each maker may use its own recipe.

For most people this makes no difference. The FDA notes that in a minority of patients, inactive ingredients may affect how well a medicine is tolerated or absorbed, and it will not approve a generic whose inactive ingredients are unsafe. If you have an allergy or intolerance, for example to lactose, gluten or a particular dye, read the ingredient list in the leaflet or ask a pharmacist before you switch.

What does bioequivalence mean?

Bioequivalence is the test that shows a generic behaves like the brand inside your body. In a typical study, volunteers take the generic and the brand at different times, and blood samples show how much medicine reaches the bloodstream and how fast. The FDA says a generic must deliver the same amount of active ingredient, at the same rate and to the same extent, as the brand.

You may read online that generics can be 20 percent stronger or weaker than the brand. The real-world numbers are much closer. When the FDA looked back at its bioequivalence studies from 1996 to 2007, the average difference between generic and brand was about 4 percent, and nearly 98 percent of studies showed differences under 10 percent, according to a review in the Canadian Medical Association Journal.

A few medicines need extra care because a small change in blood level can matter. These narrow therapeutic index drugs include some seizure medicines such as phenytoin and carbamazepine, the blood thinner warfarin, the thyroid medicine levothyroxine and the transplant medicine tacrolimus. They need careful dosing and monitoring, so tell your doctor about any switch. Your doctor may want to check your blood levels or symptoms afterward.

Why do generics cost so much less?

Bringing a new drug to market takes years of clinical trials. A generic maker does not have to repeat those trials. It relies on the safety and effectiveness already shown for the brand and proves that its own product is bioequivalent. That saves a great deal of money.

Competition does the rest. According to the FDA’s generic drug facts, a single generic competitor can bring prices down by about 30 percent, and five competing generics are linked to price drops of nearly 85 percent. A lower price does not mean a lower standard: in the US, generics are made under the same strict quality standards as brand-name medicines.

Why does my generic look different from the brand?

Generics often come in a different color, shape, size or imprint from the brand, because each maker uses its own design, coatings and dyes. The FDA allows minor differences in appearance, such as color, and says they do not affect how the medicine works.

A new look can still be confusing, especially if you take several medicines. If a refill looks different, check the name and strength on the label before you take it, and ask your pharmacist if anything does not match. Never assume two different-looking pills are the same medicine without checking.

Are Indian generics the same as US brand-name medicines?

Indian generics contain the same active ingredient as the matching US brand. They are made and licensed in India, and most are sold under the maker’s own brand name rather than the plain generic name. A few examples:

• Suhagra, made by Cipla, contains sildenafil, the same active ingredient as Viagra. Centurion Laboratories makes another sildenafil brand, Cenforce; our Cenforce vs Viagra comparison looks at how the two line up.
• Tadacip, also made by Cipla, contains tadalafil, the same active ingredient as Cialis.
• Asthalin Inhaler, from Cipla, contains albuterol (salbutamol), the same active ingredient as Ventolin HFA.

Two things often surprise people. First, Indian packs usually use international names, so you may see salbutamol instead of albuterol, or paracetamol instead of acetaminophen. Second, strengths can be written differently. US albuterol inhalers state the dose that leaves the mouthpiece, while Indian inhalers usually state the dose measured by the valve, so the numbers do not line up exactly. Our Asthalin vs Ventolin guide explains this in detail.

As with any change of brand, tell your doctor which product you are using, and try to stay on the same one once it works well for you. That matters most for the narrow therapeutic index medicines mentioned above.

What should I check on the pack?

• Active ingredient and strength. Match both to your prescription. On branded generics, the generic name is usually printed under the brand name. Letters such as IP after the name mean the product is made to the Indian Pharmacopoeia standard, much as USP refers to the US Pharmacopeia.
• Dosage form. Tablet, capsule, inhaler or cream, and whether it is a regular or an extended-release form.
• Manufacturer. The company name and address should be printed clearly.
• Batch (lot) number, manufacturing date and expiry date. Do not use a medicine after its expiry date.
• Seals and condition. Blister packs and bottle seals should be intact, and tablets should not be cracked, crumbled or discolored.
• The leaflet. It lists inactive ingredients, storage instructions and side effects. Keep it with the medicine.

When to see a doctor

Talk to your doctor before you switch any prescription medicine. Get medical help promptly if, after a switch:

• You notice signs of an allergic reaction, such as hives, a rash, or swelling of the face, lips or tongue. Call 911 if you have trouble breathing or severe swelling.
• The medicine seems to stop working, for example you need your asthma reliever more often, or your seizure control, blood pressure or blood test results change.
• You get new or stronger side effects.
• You are not sure the medicine in your hand matches your prescription.

Frequently asked questions

Are generic drugs as strong as brand-name drugs?

Yes. A generic has the same active ingredient in the same strength. A 100 mg sildenafil tablet contains 100 mg of sildenafil whether it is the brand or a generic.

Do generics cause more side effects?

They have the same possible side effects as the brand, because the active ingredient is the same. Rarely, a person reacts to an inactive ingredient such as a dye. If you suspect this, a pharmacist can help you compare ingredient lists.

Can I switch from a brand to a generic on my own?

Check with your doctor or pharmacist first, especially for seizure medicines, blood thinners, thyroid medicine or transplant drugs. Prescription medicines should always be used under a doctor’s care.

Why is the name on my Indian generic different from my prescription?

Indian companies usually sell generics under their own brand names, such as Suhagra or Asthalin. Look for the active ingredient printed on the pack. That is the name to match against your prescription.

What is an authorized generic?

An authorized generic is the brand-name drug itself, sold without the brand name on the label. It may still come in a different color or carry a different marking.

This article gives general information and does not replace advice from your doctor or pharmacist. Prescription medicines should be used only under a doctor’s care. Do not switch, stop or change the dose of a medicine without medical advice.