Medications typically follow a common route from research to development, from clinical studies to controlled release. For many drugs, once patent protection expires, the next step takes them from behind the pharmacist's counter to over-the-counter spaces. Whether they still retain patent protection or they are too dangerous for uncontrolled use, some common drugs remain available only by prescription.
Painkillers
Narcotic analgesics are by-prescription-only drugs because of their addictive quality. Derived from the same opium poppy that produces heroin, narcotics remain the most effective treatment for severe pain. Common narcotic pain relievers include morphine, hydrocodone, codeine, oxycodone and fentanyl, among many others, They also find uses when combined with non-narcotic painkillers such as acetaminophen, ibuprofen and aspirin because the two drugs together generally help speed up the pain relief, the Mayo Clinic reports. Non-narcotic pain relievers such as those mentioned often come in prescription-level doses as well as their OTC formulations.
Antihypertensives
Hypertension or high blood pressure will occur in most people at some stage of their lives, the Mayo Clinic states. It can happen for many reasons, but the end result makes the heart work too hard to pump the needed blood throughout the body. Several forms of drugs, generally called antihypertensives, can help to lower blood pressure. The most commonly prescribed types include thiazide diuretics that flush excess liquid from the body to reduce the amount of blood that needs pumping. Beta-blockers work to reduce constriction of the blood vessels, also making it easier for the blood to move around the body. ACE inhibitors---angiotensin-converting enzyme inhibitiors---cause the same effect, as do angiotensin II receptor blockers. Calcium blockers work directly in the heart to reduce the heartbeat. Renin inhibitors work differently by stopping the hypertension process in the kidneys.
Cholesterol Medications
Cholesterol appears in everyone's body as a needed agent for healthy cell creation. Higher-than-normal levels of cholesterol can create fat deposits in the blood, which decrease flow and can cause strokes and heart attacks. Many medications help reduce cholesterol levels, such as statins, which reduce the liver's production of the substances. Statins include simvastatin, rosuvastatin, lovastatin, fluvastatin and atorvastatin. Cholesterol absorption inhibitors such as ezetimibe reduce the amount of cholesterol absorption in the intestines.
Diabetes Drugs
Diabetes types I and II occur when the body cannot balance insulin, which is created in the pancreas, with the glucose or sugar ingested in food. Type I means no insulin exists in the body, while type II means not enough insulin exists to create the balance. For type I, the only course of treatment is insulin injections. For type II, however, many types of drugs can help. The most common of these, metformin, works to reduce glucose levels. Most of the other drugs, such as rosiglitazone, glyburide and pioglitazone, work to increase insulin production. Often, metformin will combine with these other medications to create the balance.
