SOURCES & NATURE OF DRUGS
Drug is a substance which is used for the following purposes:
Diagnosis of the disease
Prevention of the disease
Treatment or palliation (relief of symptoms) of disease
Prevention of pregnancy (i.e. contraception)
Maintenance of optimal health
1: Symptomatic:
Relieve disease symptoms. Aspirin, Tylenol.
2: Preventative
To avoid getting a disease. Hepatitis B vaccine, Flu vaccine.
3: Diagnostic:
Help determine disease presence. Radioactive dyes.
4: Curative:
Eliminate the disease. Antibiotics.
5: Health Maintenance:
Help keep the body functioning normally. Insulin.
6: Contraceptive:
Preventative
Sources of Drugs
Drug- ( fr. Drogue- dried herbs), medication, and medicament:
Substance administered to humans and animals for diagnosis or
treatment of diseases.
Sources of drugs are as follows:
THERE ARE FOUR SOURCES OF DRUG:
I.
NATURAL SOURCES
Most primitive and abundant.
Drugs are obtained from the following natural sources:
A)PLANTS,
B) ANIMAL SOURCES,
C) MINERAL &
D) MICROORGANISMS
A- PLANTS:
Following categories of drugs are derived from roots, leaves or barks of
plants:
a) Alkaloids
These are nitrogenous heterocyclic bases, which are
pharmacologically active principles of plants.
They are composed of carbon, hydrogen, nitrogen and oxygen.
They are bitter in taste and are often poisonous.
These are, therefore, used in small doses.
They are insoluble in water. However, they form salts with acids
which are soluble in water.
Some examples of alkaloids and their sources are listed in the table:
ALKALOID
Atropine
Quinine
Morphine
Reserpine
Nicotine
Digoxin
Caffeine
SOURCE
Atropa belladonna
Cinchona bark
Papavarum somniferum
Rauwolfia serpentine
Tobacco
Digitalis lanata
Coffee, Tea, Cocoa
b) Glycosides
They are ether-like combination of sugar moiety with non-sugar
moiety.
They are called glycosides, if the sugar moiety is glucose.
Sugar moiety is not essential for the pharmacological activity but it
governs the pharmacokinetic properties of the glycoside. In the
body it may be removed to liberate aglycone.
Pharmacological activity resides in the non-sugar moiety that is
called aglycone (orgenin).Some examples are digitoxin, digoxin
and ouabain.
c) Oils
They are liquids which are insoluble in water.
They are of three types and are used for various medicinal purposes.
i) Essential Oils (or volatile oils):
Essential oils are obtained from leaves or flower petals by steam
distillation, and have an aroma.
They have no caloric or food value.
They do not form soaps with alkalis.
They do not leave greasy stain after evaporation.
On prolonged stay, they do not become rancid (foul smell).
They are frequently used as carminatives and astringents in mouthwashes.
Some of these oils are solid at room temperature and sublime on
heating e.g. menthol and camphor.
Other examples are clove oil, peppermint oil, eucalyptus oil and
ginger oil.
ii) Fixed oils are glycerides of stearic, oleic and palmitic acid.
They are obtained from the seeds that are present within the cells
as crystals or droplets.
They are non-volatile and leave greasy stains on evaporation.
They have caloric or food value.
They form soaps with alkalies.
On prolonged stay, they become rancid.
They do not have marked pharmacological activity and have little
pharmacological use except castor oil (purgative) or arachis oil
(demulcent).
They may be of vegetable origin e.g. olive oil, castor oil, croton oil
and peanut oil or of animal origin e.g. cod liver oil, shark liver oil
and lard.
iii) Mineral Oils are mostly petroleum products and extracted by
fractional distillation.
These are mixtures of hydrocarbons of the methane and related
aliphatic series.
These are extracted in various consistencies - hard paraffin, soft
paraffin and liquid paraffin.
Hard and soft paraffins are used as vehicles for preparation of
ointments while liquidparaffin is employed as a purgative.
d) Gums are colloidal exudates from plants which are polysaccharides
chemically and yield simple sugars on hydrolysis.
Upon addition of water, some of them swell or dissolve or form adhesive
mucilage or remain unchanged.
Uses:
In gut agar and psyllium seeds act as hydrophilic colloids and
function as bulk purgatives.
Gum acacia and gum tragacanth are used as suspending agents in
making emulsions andmixtures.
e) Resins are ill-defined solid substances found in plants, and are
polymers of volatile oil.
They are produced by oxidation and polymerization of volatile
oils.
They are insoluble in water but soluble in alcohol, chloroform and
ether.
Examples: oleoresins (aspidium); gum resins (asafoetida); oleogum
resin (myrrh);balsams (benzoin, tolu, peru); benzoin shellac,
podophyllum.
Uses:
Benzoin is used as inhalation in common cold.
Tincture benzoin is applied as antiseptic protective sealing over
bruises.
Colophony (an oleoresin) is used as an ingredient in various
plasters.
Shellac (from Lucifer lacca) is used for enteric coating of tablets.
Balsams are used in the treatment of cough and bronchitis for their
antiseptic andprotective properties.
Podophyllum is used as an irritant purgative.
f) Tannins are non-nitrogenous phenolic plant constituents which have
an astringent action.
Pyrogallol tannins are glycosides of glucose that occur in oak galls.
Pyrocatechol tannins are sugar-free derivatives of catechol that are
present in catechu andeucalyptus.
Tannic acid is tannin that is obtained from oak galls and is used for
treating burns anddiarrhoea.
B-ANIMAL SOURCES
Some animal sources continue to be used to procure some modern drugs
because of cumbersome and expensive procedures for the synthesis of
such chemicals.
For example:
Insulin, extracted from pork and beef pancreas, is used for the
treatment of diabetesmellitus.
Thyroid powder for treating hypothyroidism.
Heparin is used as an anticoagulant.
Hormones and vitamins are used as replacement therapy.
Vaccines (cholera, T.B., smallpox, polio and antirabic) and sera
(antidiptheria andantitetanus) are used for prophylaxis/treatment.
C-MICROBIOLOGICAL SOURCES
Many life-saving drugs are obtained from fungi, moulds and bacteria
e.g.
penicillin from Penicillium notatum,
chloramphenicol from Streptomyces venezuelae ,
grisofulvin (an anti-fungal drug) from Penicillium griseofulvum ,
neomycin from Streptomyces fradiae and
streptomycin from Streptomyces griseus.
D-MINERAL SOURCES
Minerals or their salts are useful pharmacotherapeutic agents.
For example:
Ferrous sulfate is used in iron deficiency anaemia.
Magnesium sulfate is employed as purgative.
Magnesium trisilicate, aluminium hydroxide and sodium
bicarbonate are used as antacids for hyperacidity and peptic ulcer.
Kaolin (aluminium silicate) is used as adsorbent in antidiarrheal
mixtures.
Radioactive isotopes of iodine, phosphorus, gold are employed for
the diagnosis/ treatment of diseases particularly malignant
conditions.
II. SEMISYNTHETIC SOURCES
Sometimes semi-synthetic processes are used to prepare drugs when the
synthesis of drugs(complex molecules) may be difficult, expensive and
uneconomical or when the natural sources may yield impure
compounds.
In these situation this methods plays an important role. Some examples
are semi synthetic human insulin and 6-aminopenicillanic acid
derivatives.
Prepared by chemically modifying substances that are available from
natural source improve to improve its potency, efficacy and also reduce
side effects.
Eg.
i)Semi synthetic drugs from plant sources
Heroine from Morphine
Bromoscopolamine from scopolamine
Homoatropine from atropine.
ii) Semi synthetic drugs from animal sources:
Animal insulin changed to be like human insulin6-aminopenicillanic
acid derivatives.
III. SYNTHETIC SOURCES
At present majority of drugs used in clinical practice are prepared
synthetically, such as aspirin,oral antidiabetics, antihistamines,
amphetamine, chloroquine, chlorpromazine,
general and localanaesthetics, paracetamol, phenytoin, synthetic
corticosteroids, sulphonamides and thiazidediuretics.
Most of the synthetic drugs are prepared synthetically i.e. by chemical
process ( reaction) with the help of the knowledge of phytochemical
investigation.
Alterations are made on the naturally found structure of the drug
to improve its effect andto improve the finances of pharmaceutical
companies.
Advantages of synthetic drugs are:
They are chemically pure.
The process of preparing them is easier and cheaper.
Control on the quality of the drug is excellent.
Since the pharmacological activity of a drug depends on its
chemical structure and physical properties, more effective and
safer drugs can be prepared by modifying the chemical structure of
the prototype drug.
IV. BIOSYNTHETIC SOURCES (genetically engineered drugs)
This is relatively a new field which is being developed by mixing
discoveries from molecular biology, recombinant DNA technology,
DNA alteration, gene splicing, immunology and immunopharmacology.
Some of the recent developments are genetically engineered novel
vaccines (Recombinex HB - ahepatitis-B vaccine), recombinant DNA
engineered insulins (Humulin- human insulin) fordiabetes and
interferon-alpha-2a and interferon-alpha-2b for hairy cell leukaemia.
 For instance: genetically engineered Hepatitis-B
vaccine formation:
 Genetic material (DNA)extracted from HepatitisThe responsible gene
thatdirects the surface protein
 This gene is removed from virus DNA andinserted into
 “plasmid”.
 These Plasmids arethen inserted intoeast cells.
 Yeast is then grown byfermentation. Cells reproduceand generate
large amounts of surface protein.
 After 48 hours yeast cells areruptured to free the surface proteinwhich is
then extracted and purified.
 Large quantity of surfaceprotein thus produced isstabilized with
preservingagents and other ingredientsto make the vaccine.
 Hepatitis B Vaccine is ready
Genetic manipulation of nonpathogenic, rapidly growing bacteria, such a
E. Coli, to enable them to manufacture complex biological
compounds that would be extremely difficult or costly to prepare by
conventional means.
Recently chemists have developed computer programs to facilitate the
design of new drugs.
These programs help design chemicals that fit to the 3-D conformation
of the receptor……
-led to the discovery of HIV protease inhibitors, ACE inhibitors etc
.
Drug Preparations-What are the differences?
CrudePure- ?
PharmaceuticalsDrug Preparations
Crude drug preparations
Drying, Pulverizing
Extraction; Alcohol, hotwater>Coffee, Tea, Opium
Pure drug compounds
Morphine, Insulin
Pharmaceutical preparations
Figure 1
Types of drug preparations.
A crude drug preparation retains most or all of the active and inactive
compounds contained in the natural source from which it was derived.
After a pure drug compound (e.g., morphine) is extractedfrom a crude
drug preparation (in this case, opium), it is possible to manufacture
pharmaceutical preparations that are suitable for administration of a
particular dose to the patient.
Expected Question??
Write a note about the sources of drugs with example.
Why are synthetic drugs used most widely?
Write a note about biosynthetic sources of drug along with example.
Classification
Medications can be classified in various ways,[3] 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 (ATC system). The World Health Organization keeps a list
of essential medicines.
A sampling of classes of medicine includes:
1.
2.
3.
4.
5.
Antipyretics: reducing fever (pyrexia/pyresis)
Analgesics: reducing pain (painkillers)
Antimalarial drugs: treating malaria
Antibiotics: inhibiting germ growth
Antiseptics: prevention of germ growth
near burns, cuts and wounds
Types of medications (type of pharmacotherapy)
For the gastrointestinal tract (digestive system)


Upper digestive tract: antacids, reflux
suppressants, antiflatulents, antidopaminergics, proton pump
inhibitors (PPIs), H2-receptor
antagonists, cytoprotectants, prostaglandin analogues
Lower digestive
tract: laxatives, antispasmodics, antidiarrhoeals, bile acid
sequestrants, opioid
For the cardiovascular system




General: β-receptor blockers ("beta blockers"), calcium channel
blockers, diuretics, cardiac
glycosides, antiarrhythmics, nitrate, antianginals, vasoconstrictors,
vasodilators, peripheral activators
Affecting blood pressure (antihypertensive drugs): ACE
inhibitors, angiotensin receptor blockers, α blockers, calcium
channel blockers
Coagulation: anticoagulants, heparin, antiplatelet
drugs, fibrinolytics, anti-hemophilic factors, haemostatic drugs
Atherosclerosis/cholesterol inhibitors: hypolipidaemic
agents, statins.
For the central nervous system
See also: Psychiatric medication and Psychoactive drug
Drugs affecting the central nervous
system include: hypnotics, anaesthetics, antipsychotics, antidepressants (
including tricyclic antidepressants, monoamine oxidase
inhibitors, lithium salts, and selective serotonin reuptake
inhibitors (SSRIs)), antiemetics, anticonvulsants/antiepileptics, anxiolyti
cs, barbiturates, movement disorder (e.g., Parkinson's disease)
drugs, stimulants (including amphetamines), benzodiazepines,cyclopyrro
lones, dopamine
antagonists, antihistamines, cholinergics, anticholinergics, emetics, cann
abinoids, and 5-HT (serotonin) antagonists.
For pain and consciousness (analgesic drugs)
See also: Analgesic
The main classes of painkillers are NSAIDs, opioids and
various orphans such as paracetamol.
For musculo-skeletal disorders
The main categories of drugs for musculoskeletal
disorders are: NSAIDs (including COX-2 selective inhibitors), muscle
relaxants, neuromuscular drugs, and anticholinesterases.
For the eye








General: adrenergic neurone blocker, astringent, ocular lubricant
Diagnostic: topical
anesthetics, sympathomimetics, parasympatholytics, mydriatics, cy
cloplegics
Anti-bacterial: antibiotics, topical antibiotics, sulfa
drugs, aminoglycosides, fluoroquinolones
Antiviral drug
Anti-fungal: imidazoles, polyenes
Anti-inflammatory: NSAIDs, corticosteroids
Anti-allergy: mast cell inhibitors
Anti-glaucoma: adrenergic agonists, beta-blockers, carbonic
anhydrase
inhibitors/hyperosmotics, cholinergics, miotics, parasympathomim
etics, prostaglandin agonists/prostaglandin inhibitors. nitroglycerin
For the ear, nose and oropharynx
sympathomimetics, antihistamines, anticholinergics, NSAIDs, steroids, a
ntiseptics, local anesthetics, antifungals, cerumenolyti
For the respiratory system
bronchodilators, NSAIDs, antiallergics, antitussives, mucolytics, decongestants
corticosteroids, Beta2-adrenergic agonists, anticholinergics, steroids
For endocrine problems
androgens, antiandrogens, gonadotropin, corticosteroids, human growth
hormone, insulin, antidiabetics (sulfonylureas, biguanides/metformin, thi
azolidinediones, insulin), thyroid hormones, antithyroid
drugs,calcitonin, diphosponate, vasopressin analogues
For the reproductive system or urinary system
antifungal, alkalising
agents, quinolones, antibiotics, cholinergics, anticholinergics, anticholin
esterases, antispasmodics, 5-alpha reductase inhibitor, selective alpha-1
blockers, sildenafils, fertility medications
For contraception



Hormonal contraception
Ormeloxifene
Spermicide
For obstetrics and gynecology
NSAIDs, anticholinergics, haemostatic drugs, antifibrinolytics, Hormone
Replacement Therapy (HRT), bone regulators, beta-receptor
agonists, follicle stimulating hormone, luteinising hormone, LHRH
gamolenic acid, gonadotropin release inhibitor, progestogen, dopamine
agonists, oestrogen, prostaglandins, gonadorelin, clomiphene, tamoxifen,
Diethylstilbestrol
For the skin
emollients, antipruritics, antifungals, disinfectants, scabicides, pediculicides, tar product
s, vitamin A derivatives, vitamin D
analogues, keratolytics, abrasives, systemic
antibiotics, topical antibiotics, hormones,desloughing agents, exudate
absorbents, fibrinolytics, proteolytics, sunscreens, antiperspirants, cortic
osteroids
For infections and infestations
antibiotics, antifungals, antileprotics, antituberculous
drugs, antimalarials, anthelmintics, amoebicides, antivirals, antiprotozoa
ls
For the immune system
vaccines, immunoglobulins, immunosuppressants, interferons, monoclon
al antibodies
For allergic disorders
anti-allergics, antihistamines, NSAIDs
For nutrition
tonics, electrolytes and mineral preparations (including iron
preparations and magnesium preparations), parenteral nutritional
supplements, vitamins, anti-obesity drugs, anabolic
drugs, haematopoietic drugs, food product drugs
For neoplastic disorders
cytotoxic drugs, therapeutic antibodies, sex hormones, aromatase
inhibitors, somatostatin inhibitors, recombinant interleukins, GCSF, erythropoietin
For diagnostics
contrast media
For euthanasia
See also: Barbiturate#Other non-therapeutical uses and barbituates
An euthanaticum is used for euthanasia and physician-assisted suicide.
Euthanasia is not permitted by law in many countries, and consequently
medicines will not be licensed for this use in those countries.
Administration
Administration is the delivery of a pharmaceutical drug to a patient.
It can be performed in various dosage forms such as pills, tablets,
or capsules.
There are also many variations in the routes of administration,
including intravenous (into the blood through a vein) and oral
administration (through the mouth).
They can be administered all at once as a bolus, at frequent intervals or
continuously. Frequencies are often abbreviated from Latin, such
as every 8 hours reading Q8H from Quaque VIII Hora.
Legal considerations
Depending upon the jurisdiction, medications may be divided into overthe-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. In 2000 the definition of a prescription error was studied
using aDelphi method conference; the conference was motivated by
ambiguity in the what a prescription error and a need to use a uniform
definition in studies.[4]
Development
Main article: 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. Childresistant 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.[5]
A report from URCH Publishing estimated that about one third of the
pharma market by value is accounted for by blockbusters. About 125
products are blockbusters. The top seller was Lipitor, a cholesterollowering medication marketed by Pfizer with sales of $12.5 billion.
In 2009 there were a total of seven new blockbuster drugs, with
combined sales of $9.8 billion.
Beyond this purely arbitrary financial consideration,
"In the pharmaceutical industry, a blockbuster drug is one that
achieves acceptance by prescribing physicians as a therapeutic
standard for, most commonly, a highly prevalent chronic (rather
than acute) condition. Patients often take the medicines for long
periods."[6]
The birth control pill Enovid was the first modern drug taken by those
not ill for a highly prevalent chronic condition. The focus on highly
profitable drugs for chronic conditions and resulting de-emphasis of onetime acute treatment drugs has led to occasional shortages of antibiotics
or vaccines, such as the influenza vaccine shortage in the United States.
Leading blockbuster drugs
Drug
Trade
Indication
name
Company
Sales[7] ($billion
/year)*
Drug
Trade
Indication
name
Atorvastatin
Lipitor
Clopidogrel
BristolMyers
Plavix atherosclerosis
Squibb
Sanofi
Company
hypercholester
Pfizer
olemia
Fluticasone/sal Seretid
asthma
meterol
e
Sales[7] ($billion
/year)*
12.5
9.1
GlaxoSmith
8.7
Kline
Esomeprazole
Nexiu acid reflux
m
disease
Rosuvastatin
Crestor
Quetiapine
bipolar
Seroqu
disorder
el
schizophrenia
AstraZeneca 7.2
Adalimumab
Humir rheumatoid
a
arthritis
Abbott
AstraZeneca 8.3
hypercholester
AstraZeneca 7.4
olemia
6.6
Company
Sales[7] ($billion
/year)*
Amgen
Pfizer
6.5
Drug
Trade
Indication
name
Etanercept
Enbrel
Infliximab
Crohn's disease
Remic
Johnson &
rheumatoid
ade
Johnson
arthritis
6.4
Olanzapine
Zyprex
schizophrenia
a
6.2
rheumatoid
arthritis
Eli Lilly
*
Sales are for the 12 months preceding June 30, 2011.
Environmental impact
Main article: Pharmaceuticals and personal care products in the
environment
Since the 1990s water contamination by pharmaceuticals has been
an environmental issue of concern.[8] Most pharmaceuticals are
deposited in the environment through human consumption and
excretion, and are often filtered ineffectively by wastewater treatment
plants which are not designed to manage them. Once in the water they
can have diverse, subtle effects on organisms, although research is
limited. Pharmaceuticals may also be deposited in the environment
through improper disposal, runoff from sludge fertilizer and reclaimed
wastewater irrigation, and leaky sewage.[8] In 2009 an investigative
report byAssociated Press concluded that U.S. manufacturers had legally
released 271 million pounds of drugs into the environment, 92% of
which was the antiseptics phenol and hydrogen peroxide. It could not
distinguish between drugs released by manufacturers as opposed to
the pharmaceutical industry. It also found that an estimated 250 million
pounds of pharmaceuticals and contaminated packaging were discarded
by hospitals and long-term care facilities.[9]
Pharmacoenvironmentology is a branch of pharmacology and a form
of pharmacovigilance which deals entry of chemicals or drugs into
the environment after elimination from humans and animals posttherapy. It deals specifically with those pharmacological agents that
have impact on the environment via elimination through living
organisms subsequent to pharmacotherapy, while Ecopharmacology is
concerned with the entry of chemicals or drugs into the environment
through any route and at any concentration disturbing the balance of
ecology (ecosystem), as a consequence. Ecopharmacology is a broad
term that includes studies of “PPCPs” irrespective of doses and route of
entry into environment.[10][11][12]
Ecopharmacovigilance is the science and activities associated with the
detection, evaluation, understanding and prevention of adverse effects of
pharmaceuticals in the environment. This is close to the WHO definition
of pharmacovigilance, the science aiming to capture any adverse effects
of pharmaceuticals in humans after use.[13]
The term Environmental Persistent Pharmaceutical Pollutants (EPPP)
was suggested in the 2010 nomination of pharmaceuticals and
environment as an emerging issue to Strategic Approach to International
Chemicals Management (SAICM) by the International Society of
Doctors for the Environment (ISDE).
History
Ancient pharmacology
Using plants and plant substances to treat all kinds of diseases and
medical conditions is believed to date back to prehistoric medicine.
The Kahun Gynaecological Papyrus, the oldest known medical text of
any kind, dates to about 1800 BC and represents the first documented
use of any kind of medication.[14][15] It and other medical
papyridescribe Ancient Egyptian medical practices, such as
using honey to treat infections.
Ancient Babylonian medicine demonstrate the use of prescriptions in the
first half of the 2nd millennium BC. Medicinal creams and pills were
employed as treatments.[16]
On the Indian subcontinent, the Atharvaveda, a sacred text
of Hinduism whose core dates from the 2nd millennium BC, although
the hymns recorded in it are believed to be older, is the first Indic text
dealing with medicine. It describes plant-based medications to counter
diseases.[17] The earliest foundations of ayurveda were built on a
synthesis of selected ancient herbal practices, together with a massive
addition of theoretical conceptualizations, new nosologies and new
therapies dating from about 400 BC onwards.[18] The student of
Āyurveda was expected to know ten arts that were indispensable in the
preparation and application of his medicines: distillation, operative
skills, cooking, horticulture, metallurgy, sugar manufacture, pharmacy,
analysis and separation of minerals, compounding of metals, and
preparation of alkalis.
The Hippocratic Oath for physicians, attributed to 5th century BC
Greece, refers to the existence of "deadly drugs", and ancient Greek
physicians imported medications from Egypt and elsewhere.[19]
The first drugstores were created in Baghdad in the 8th century AD.
The injection syringe was invented by Ammar ibn Ali al-Mawsili in 9th
century Iraq. Al-Kindi's 9th century AD book, De Gradibus, developed
a mathematical scale to quantify the strength of drugs.[20]
The Canon of Medicine by Ibn Sina (Avicenna), who is considered the
father of modern medicine,[21] reported 800 tested drugs at the time of its
completion in 1025 AD.[citation needed] Ibn Sina's contributions include the
separation of medicine from pharmacology, which was important to the
development of the pharmaceutical sciences.[22] Islamic medicine knew
of at least 2,000 medicinal and chemical substances.[23]
Medieval pharmacology
Medieval medicine saw advances in surgery, but few truly effective
drugs existed, beyond opium and quinine. Folklore cures and potentially
poisonous metal-based compounds were popular treatments.Theodoric
Borgognoni, (1205–1296), one of the most significant surgeons of the
medieval period, responsible for introducing and promoting important
surgical advances including basic antiseptic practice and the use
of anaesthetics. Garcia de Orta described some herbal treatments that
were used.
Modern pharmacology
For most of the 19th century, drugs were not highly effective,
leading Oliver Wendell Holmes, Sr. to famously comment in 1842 that
"if all medicines in the world were thrown into the sea, it would be all
the better for mankind and all the worse for the fishes".[24]:21
During the First World War, Alexis Carrel and Henry Dakin developed
the Carrel-Dakin method of treating wounds with an irrigation, Dakin's
solution, a germicide which helped prevent gangrene.
In the inter-war period, the first anti-bacterial agents such as
the sulpha antibiotics were developed. The Second World War saw the
introduction of widespread and effective antimicrobial therapy with the
development and mass production of penicillin antibiotics, made
possible by the pressures of the war and the collaboration of British
scientists with the American pharmaceutical industry.
Medicines commonly used by the late 1920s included aspirin, codeine,
and morphine for pain; digitalis, nitroglycerin, and quinine for heart
disorders, and insulin for diabetes. Other drugs included antitoxins, a
few biological vaccines, and a few synthetic drugs. In the 1930s
antibiotics emerged: first sulfa drugs, then penicillin and other
antibiotics. Drugs increasingly became "the center of medical
practice".[24]:22 In the 1950s other drugs emerged
including corticosteroids for inflammation, rauwolfia alkloids as
tranqulizers and antihypertensives, antihistamines for nasal
allergies, xanthines for asthma, and typical antipsychotics for
psychosis.[24]:23-24 As of 2008, thousands of approved drugs have
been developed. Increasingly, biotechnology is used to
discover biopharmaceuticals.[24] Recently, multi-disciplinary approaches
have yielded a wealth of new data on the development of novel
antibiotics and antibacterials and on the use of biological agents for
antibacterial therapy.[25]
In the 1950s new psychiatric drugs, notably the
antipsychotic chlorpromazine, were designed in laboratories and slowly
came into preferred use. Although often accepted as an advance in some
ways, there was some opposition, due to serious adverse effects such
as tardive dyskinesia. Patients often opposed psychiatry and refused or
stopped taking the drugs when not subject to psychiatric control.
Governments have been heavily involved in the regulation of drug
development and drug sales. In the U.S., the Elixir Sulfanilamide
disaster led to the establishment of the Food and Drug Administration,
and the 1938 Federal Food, Drug, and Cosmetic Act required
manufacturers to file new drugs with the FDA. The 1951 HumphreyDurham Amendment required certain drugs to be sold by prescription. In
1962 a subsequent amendment required new drugs to be tested for
efficacy and safety in clinical trials.[24]:24-26
Until the 1970s, drug prices were not a major concern for doctors and
patients. As more drugs became prescribed for chronic illnesses,
however, costs became burdensome, and by the 1970s nearly every U.S.
state required or encouraged the substitution of generic drugs for higherpriced brand names. This also led to the 2006 U.S. law, Medicare Part
D, which offers Medicare coverage for drugs.[24]:28-29
As of 2008, the United States is the leader in medical research, including
pharmaceutical development. U.S. drug prices are among the highest in
the world, and drug innovation is correspondingly high. In 2000 U.S.
based firms developed 29 of the 75 top-selling drugs; firms from the
second-largest market, Japan, developed eight, and the United Kingdom
contributed 10. France, which imposes price controls, developed three.
Throughout the 1990s outcomes were similar.
Drug Nomenclature/Naming of Drugs, Rules for Drug
Administration
Introduction
Drugs are classifies into convenient groups for the sake of conformity,
standardization, esoteric values of manufactures, research and
replication and quality asurance. There are basically three classes of
drugs which is recognized by drug companies and regulatory bodies.
At the end of the lesson the learners will;
1. Discuss the accepted approach to drug classification
2. Distinguish between the various drug names of; chemical, generic
and tradename
3. Identify why the generic names are prefered over the chemical and
trade names of drugs
4. Discuss the rules of drug administration as a component of safe
effective nursing care.
5. Explain the steps that the nurse should take to ensure drug
complaince
6. Discribe the role and responsibilities of the nurse in drug
administration.
7. Explain the steps to take in ensuring wholesomeness of drugs.
Lesson Content
Drug Nomenclature/Naming of Drugs
This is the system that puts drugs into classification and the three name
classifications of drugs are the Chemical/Molecular/Scientific name, the
Generic or Non-Proprietary name, and the Brand or Trade or Proprietary
name.
Chemical names; convenient components for laboratory inventions and
replication; assures quality, Image provided by courtesy of commonscommons.wikimedia.org
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Chemical Name: It depicts the chemical/molecular structure of the
drug. It states the structure in terms of atoms and molecules
accompanied by a diagram of the chemical structure. They are long
and can be clumsy and are useful to a few technically trained
personnel. For example acetyl-p-amino-phenol is for Paracetamol
and the image above gives the structure of Vitamin C.
Non-Proprietary/Generic/Approved Name: This is the abbreviated
and approved name of the drug. It is the official medical name
assigned by the producer in collaboration with the Food and Drugs
Board and Nomenclature Committee. The generic name may be
used by any interested party and it removes the confusion of giving
several names to the same drug regardless of who manufactures
them once they have the same chemical structure. A generic drug
name is not capitalized; for example, aluminum hydroxide.
Proprietary/Trade/Brand Name: These are names given to the drug
by the manufacturing and marketing company. They are
copyrighted terms selected by a manufacturer to designate a
particular product Copyright laws prevent any other person from
using the name, and other laws prevent pharmacists from
substituting chemically identical products for the trade name
article. In most cases one drug could have so many trade/brand
names e.g Acetaminophen has about 30 trade names. Some are
Paracetamol, Tylenol, Paramol, Panadol, Capol etc.
Two major methods of dispensing drugs
Drugs are mainly available by prescription or as over the counter (OTC)
medication and the same methods two major methods are used for
dispensing the drugs There are advantages and disadvantages to both
methods of dispensing. The methods are explained thus;
1. Over-The-Counter (OTC): They do not need prescription and can
be purchased at the chemical shops; examples are pain relievers,
blood tonics, vitamin preparations, ORS, antacids, Antimalarials
etc.
2. Prescription: They need a prescription and must be controlled from
abuse and dependence; e.g. antibiotics, anti-hypertensives,
sedatives, diabetic drugs etc.
Rules For Drug Administration
1. Read the drug prescription and be sure the medicine goes to right
patient
2. Check drug for accuracy with the label especially where the drug
in not in original container
3. Drug strength should correspond to the stated dosage e.g.
Chloroquine may be 150mg or 200mg, Ampicillin 250mg and
500mg so client be should given according to strength which
reflects the dosage and not quantity.
4. Look at the expiry date, color, consistency of drug and make sure it
is wholesome. Discard when drug is discolored, tablets are brittle,
soft, cracked or powders and granules are caked.
5. Use special handling if required
6. Give information on user, quantity to be taken, how often,
duration, precautions and special instructions if necessary
7. Keep accurate record of drugs given, dosage, routes of
administration and the data on patient.
8. Promote compliance
Conclusion
The three class names of drugs are largely employed in the manufacture,
prescription and trading activities of medicines. Though we have a large
array of drugs for our use it is not always that the individual acquires the
drug over the counter. Sometimes you may need to rely on the
appropriate prescriber. Drugs are useful under many conditions of living
organisms and nurses as members of the medical team have well spelt
out responsibilities in follwing laid down rules and regulations.
1. Differentiate between the three recognized class names of drugs
2. List 10 drugs that can be obtained OTC and 10 that must be
obtained with the physicians prescription order.
3. Briefly discuss how you will present drugs to patients to ensure
compliance.
DRUG NOMENCLATUREThe term drug nomenclature implies that
there areseveral names that can be used to identify a drug.Normally
drugs have three names: chemical, generic,and trade
(brand).Chemical name—Describes the chemical andmolecular
structure. The chemical name of a commondental local anesthetic
called acetamide is2-(diethylamino)-N-(2,6-dimethylphenyl)monohydrochloride (C14H22N2O.HCL.H2O).Generic name—Describes
the common name ofthe drug. The above example has the generic name
oflidocaine hydrochloride.Trade name—This name is given by
themanufacturer, and is also called the brand name