Medication
Medication is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy is an important part of the medical field and relies on the science of pharmacology for continual advancement and on pharmacy for appropriate management.
Drugs are classified in many ways. One of the key divisions is by level of control, which distinguishes prescription drugs from over-the-counter drugs. Medicines may be classified by mode of action, route of administration, biological system affected, or therapeutic effects. The World Health Organization keeps a list of essential medicines.
Drug discovery and drug development are complex and expensive endeavors undertaken by pharmaceutical companies, academic scientists, and governments. As a result of this complex path from discovery to commercialization, partnering has become a standard practice for advancing drug candidates through development pipelines. Governments generally regulate what drugs can be marketed, how drugs are marketed, and in some jurisdictions, drug pricing. Controversies have arisen over drug pricing and disposal of used medications.
Definition
Medication is a medicine or a chemical compound used to treat or cure illness. According to Encyclopædia Britannica, medication is "a substance used in treating a disease or relieving pain".As defined by the National Cancer Institute, dosage forms of medication can include tablets, capsules, liquids, creams, and patches. Medications can be administered in different ways, such as by mouth, by infusion into a vein, or by drops put into the ear or eye. A medication that does not contain an active ingredient and is used in research studies is called a placebo.
In Europe, the term is "medicinal product", and it is defined by EU law as:
- "Any substance or combination of substances presented as having properties for treating or preventing disease in human beings; or"
- "Any substance or combination of substances which may be used in or administered to human beings either with a view to restoring, correcting, or modifying physiological functions by exerting a pharmacological, immunological or metabolic action or to making a medical diagnosis."
- A substance intended to affect the structure or any function of the body.
- A substance intended for use as a component of a medicine but not a device or a component, part, or accessory of a device.
- A substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease.
- A substance recognized by an official pharmacopeia or formulary.
- Biological products are included within this definition and are generally covered by the same laws and regulations, but differences exist regarding their manufacturing processes.
Usage
Classification
One of the key classifications is between traditional small molecule drugs; usually derived from chemical synthesis and biological medical products; which include recombinant proteins, vaccines, blood products used therapeutically, gene therapy, and cell therapy.Pharmaceuticals or drugs or medicines are classified into various other groups besides their origin on the basis of pharmacological properties like mode of action and their pharmacological action or activity, such as by chemical properties, mode or route of administration, biological system affected, or therapeutic effects. An elaborate and widely used classification system is the Anatomical Therapeutic Chemical Classification System. The World Health Organization keeps a list of essential medicines.
Pharmaceuticals may also be described as "specialty", independent of other classifications, which is an ill-defined class of drugs that might be difficult to administer, require special handling during administration, require patient monitoring during and immediately after administration, have particular regulatory requirements restricting their use, and are generally expensive relative to other drugs.
Classification By Function
Medicines may be classified by their therapeutic function—that is, the role they play in treating or preventing disease. The following table summarizes common categories of medications by their primary use:| Type | Definition | Examples |
| Analgesics | Used to relieve pain | Acetylsalicylic acid, acetaminophen, ibuprofen |
| Antibiotics | Used to kill or inhibit the growth of bacteria | Penicillin, amoxicillin, ciprofloxacin |
| Antifungals | Used to kill or inhibit the growth of fungal pathogens | Clotrimazole, fluconazole, metronidazole |
| Antihistamines | Used to reduce allergy symptoms | Diphenhydramine, cetirizine, loratadine |
| Antipyretics | Used to reduce fever | Acetylsalicylic acid, acetaminophen |
| Antivirals | Used to kill or inhibit the growth of viral pathogens | Acyclovir, ganciclovir, oseltamivir |
| Anticoagulants | Used to prevent blood clot formation | Apixaban, heparin, enoxaparin |
| Antidepressants | Used to manage depression and related mental health conditions | Sertraline, fluoxetine, bupropion |
| Antineoplastics | Used in the treatment of cancer | Cyclophosphamide, etoposide |
| Antipsychotics | Used to manage severe mental health conditions | Haloperidol, clozapine, aripiprazole |
| Bronchodilators | Used to open the airways in the lungs | Albuterol, formoterol, tiotropium |
| Corticosteroids | Used to reduce inflammation throughout the body | Dexamethasone, prednisone, triamcinolone |
| Mood Stabilizers | Used to treat bipolar disorder and other mood-related conditions | Lithium, lamotrigine |
| Statins | Used to lower blood cholesterol levels | Atorvastatin, rosuvastatin, pravastatin |
| Antacids | Neutralize stomach acid to relieve heartburn and indigestion | Calcium carbonate, magnesium hydroxide |
| Proton pump inhibitors | Reduce stomach acid production by blocking proton pumps | Omeprazole, pantoprazole, lansoprazole |
| H2 receptor antagonists | Reduce stomach acid by blocking histamine H2 receptors | Famotidine, ranitidine |
| Antiemetics | Used to prevent or treat nausea and vomiting | Ondansetron, metoclopramide, promethazine |
| Anticonvulsants | Used to manage or prevent seizures | Valproic acid, carbamazepine, oxcarbazepine |
| Diuretics | Promote urine production to reduce fluid overload and lower blood pressure | Furosemide, hydrochlorothiazide, bumetanide |
| Beta blockers | Lower heart rate and blood pressure by blocking beta-adrenergic receptors | Metoprolol, propranolol, atenolol |
| Calcium channel blockers | Relax blood vessels and reduce blood pressure | Amlodipine, diltiazem, nicardipine, clevidipine |
| ACE Inhibitors | Lower blood pressure by inhibiting angiotensin-converting enzyme | Enalapril, ramipril, lisinopril |
| Antidiabetics | Used to manage blood glucose levels in diabetes | Metformin, insulin, gliclazide |
| Thyroid hormones | Replace or supplement thyroid hormone levels | Levothyroxine, liothyronine, |
| Hormonal contraceptives | Prevent pregnancy by altering hormonal regulation | ethinyl estradiol/norgestimate, levonorgestrel |
| Sedatives / Hypnotics | Induce or maintain sleep, reduce anxiety | Zopiclone, alprazolam, zolpidem |
| Stimulants | Enhance alertness, attention, and energy | Methylphenidate, amphetamine, caffeine |
| Immunosuppressants | Suppress immune response to prevent organ rejection or treat autoimmune disease | Cyclosporine, tacrolimus, adalimumab |
| Vaccines | Stimulate the immune system to prevent infectious disease | Influenza vaccine, MMR, COVID-19 mRNA vaccines |
By Administration
Medicines can also be categorized based on how they are administered. The route of administration can affect the speed and effectiveness of treatment. Below is a summary of common routes:Drug discovery
In the fields of medicine, biotechnology, and pharmacology, drug discovery is the process by which new drugs are discovered.Historically, drugs were discovered by identifying the active ingredient from traditional remedies or by serendipitous discovery. Later chemical libraries of synthetic small molecules, natural products, or extracts were screened in intact cells or whole organisms to identify substances that have a desirable therapeutic effect in a process known as classical pharmacology. Since sequencing of the human genome which allowed rapid cloning and synthesis of large quantities of purified proteins, it has become common practice to use high throughput screening of large compound libraries against isolated biological targets which are hypothesized to be disease-modifying in a process known as reverse pharmacology. Hits from these screens are then tested in cells and then in animals for efficacy. Even more recently, scientists have been able to understand the shape of biological molecules at the atomic level and to use that knowledge to design drug candidates.
Modern drug discovery involves the identification of screening hits, medicinal chemistry, and optimization of those hits to increase the affinity, selectivity, efficacy/potency, metabolic stability, and oral bioavailability. Once a compound that fulfills all of these requirements has been identified, it will begin the process of drug development prior to clinical trials. One or more of these steps may, but not necessarily, involve computer-aided drug design.
Despite advances in technology and understanding of biological systems, drug discovery is still a lengthy, "expensive, difficult, and inefficient process" with a low rate of new therapeutic discovery. In 2010, the research and development cost of each new molecular entity was approximately US$1.8 billion. Drug discovery is done by pharmaceutical companies, sometimes with research assistance from universities. The "final product" of drug discovery is a patent on the potential drug. The drug requires very expensive Phase I, II, and III clinical trials, and most of them fail. Small companies have a critical role, often then selling the rights to larger companies that have the resources to run the clinical trials.
Drug discovery is different from Drug Development. Drug Discovery is often considered the process of identifying new medicine. At the same time, Drug development is delivering a new drug molecule into clinical practice. In its broad definition, this encompasses all steps from the basic research process of finding a suitable molecular target to supporting the drug's commercial launch.