If a doctor has prescribed you generic medication, you’re not alone: generic drugs are very common. Ninety percent of prescription drugs dispensed in the United States are generics. Most physicians prescribe generic medication because they are proven to be as effective as brand name medication and much cheaper. In 2014, generic medication accounted for 88% of all drugs dispensed in the U.S., but only 28% of money spent on prescription medication. The U.S. Food and Drug Administration (FDA) estimates that generic drugs are 80-85% cheaper than brand name analogues, and saved Americans $158 billion dollars in 2015. Because generics drugs are both cheaper and just as effective, insurance companies may not cover brand name prescription drugs if a suitable generic drug is available. This means that you, like many Americans, may never take brand name medication.
You may wonder if generic drugs are as effective as brand name drugs. The short answer is yes: generic drugs are as medicinally effective as brand name drugs. Generic drug manufacturers must prove this is the case—a term called bioequivalence—before a generic will be approved by the FDA, which oversees bioequivalence compliance and other regulatory aspects of generic pharmaceuticals. Bioequivalence refers to the rate of absorption of the active component of a drug so that it is available at the targeted site in the body.
For a generic to be bioequivalent, the generic must deliver the same amount of drug to the targeted area as its brand name equivalent. Generics must have identical delivery methods (such as an injectable or a syrup), the same time-release technology (such as immediate or extended release), and the same active ingredient as the name brand. This way, the same amount of medication is delivered to the area of the body to be treated and is just as effective at treating the illness or condition. Due to natural variability and the fact that the generic must have different design aspects (such as size, color, and shape), there may be a slight difference in absorption between the generic and brand name drugs. The FDA reports that the average difference in absorption between the brand name and generic drugs is about 3.5%, with some generics absorbing more, and some less. This is within tolerable range, and for most drugs, is safe.
There can be physical and chemical variability between a generic and brand name drug. For instance, inactive ingredients do not have to be the same in generic medications. Inactive ingredients include coatings, flavorings, and binders. Generic drug companies must prove that inactive ingredients are not medicinally important and do not hinder the bioequivalence of their product.
In some cases, the slight differences between brand name and generic drugs are very important, and some brand name drugs are not interchangeable with generic versions. One example is warfarin, an anticoagulant drug. The legally acceptable difference in absorption between the generic and brand name medication greatly affects the drug’s effectiveness. Physicians usually prescribe brand name medications when there is little difference between an effective and a toxic dose, such as digoxin (used to treat heart failure). Because generic drugs may cause changes in seizure management, most anti-epileptic drugs are not interchangeable. Finally, inactive ingredients may trigger allergic or adverse reactions that make the brand name medication preferable over its generic analogue. In this case, physicians will prescribe the brand name medication and pharmacists must fill the prescription exactly as written. Although they are sometimes the only option available, brand name medication is still very expensive, and insurance companies are likely to require higher copays or refuse to cover the cost of the medication. This makes brand names drugs a very costly option.
Since the government enacted the Drug Price Competition and Patent Term Restoration Act (informally the Hatch-Waxman Act) in 1984, generic drugs have become more available and have saved Americans trillions of dollars on medication. The Hatch-Waxman Act created a culture of prescribing and dispensing generic drugs when available, and established the modern governmental regulatory system of generic drugs. Consequentially, generic drugs have become safer, cheaper, and widely available. So don’t worry—decades of testing and regulatory oversight have ensured that the generic drug your doctor has prescribed to you is just as effective as the brand name—at only a fraction of the cost.