Text b. Pharmaceutical drugs

A pharmaceutical drug, also referred to as a medicine or medication, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease. The word pharmaceutical comes from the Greek word Pharmakeia. The modern transliteration of Pharmakeia is Pharmacia.

Administration is the delivery of a pharmaceutical drug to a patient. There are three major categories of drug administration: enteral (taking medication orally), parenteral (introducing the medication directly to the circulatory system), and other (which includes introducing medication through intranasal, topical, inhalation, and rectal means). It can be performed in various dosage forms such as pills, tablets, or capsules. There are many variations in the routes of administration, including intravenous (into the blood through a vein) and oral administration (through the mouth).

Legal considerations. Depending upon the jurisdiction, medications may be divided into over-the-counter drugs (OTC), which may be available without special restrictions, and prescription only medicine (POM), which must be prescribed by a licensed medical practitioner. The precise distinction between OTC and prescription depends on the legal jurisdiction. A third category, behind-the-counter medications (BTMs), is implemented in some jurisdictions. BTMs do not require a prescription, but must be kept in the dispensary, not visible to the public, and only be sold by a pharmacist or pharmacy technician. Doctors may also prescribe prescription drugs for off-label use - purposes which the drugs were not originally approved for by the regulatory agency. The Classification of Pharmaco-Therapeutic Referrals helps guide the referral process between pharmacists and doctors.

The International Narcotics Control Board of the United Nations imposes a world law of prohibition of certain medications. They publish a lengthy list of chemicals and plants whose trade and consumption (where applicable) is forbidden. OTC medications are sold without restriction as they are considered safe enough that most people will not hurt themselves accidentally by taking it as instructed. Many countries, such as the United Kingdom have a third category of pharmacy medicines which can only be sold in registered pharmacies, by or under the supervision of a pharmacist.

For patented medications, countries may have certain mandatory licensing programs which compel, in certain situations, a medication's owner to contract with other agents to manufacture the drug. Such programs may deal with the contingency of a lack of medication in the event of a serious epidemic of disease, or may be part of efforts to ensure that disease treating drugs, such as AIDS drugs, are available to countries which cannot afford the drug owner's price.

Prescription practice. Drugs which are prescription only are regulated as such because they can impose adverse effects and should not be used unless necessary. Medical guidelines and clinical trials required for approval are used to help inform doctors' prescription of these drugs, but errors can happen. Reasons to not prescribe drugs such as interactions or side effects are called contraindications. Errors include overprescription and polypharmacy, misprescription, contraindication and lack of detail in dosage and administrations instructions.

Drug development. Drug development is the process by which a drug is created. Drugs can be extracted from natural products (pharmacognosy) or synthesized through chemical processes. The drug’s active ingredient will be combined with a “vehicle” such as a capsule, cream, or liquid which will be administered through a particular route of administration. Child-resistant packaging will likely be used in the ultimate package sold to the consumer.

Blockbuster drug. A blockbuster drug is a drug generating more than $1 billion of revenue for its owner each year. Cimetidine was the first drug ever to reach more than $1 billion a year in sales, thus making it the first blockbuster drug. In the pharmaceutical industry, a blockbuster drug is one that achieves acceptance by prescribing physicians as a therapeutic standard for, most commonly, a highly prevalent chronic (rather than acute) condition. Patients often take the medicines for long periods. The birth control pill Enovid was the first modern drug taken by those not ill for a highly prevalent chronic condition. The focus on highly profitable drugs for chronic conditions and resulting de-emphasis of one-time acute treatment drugs has led to occasional shortages of antibiotics or vaccines, such as the influenza vaccine shortage.