Medicines New

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MEDICINES



Drugs are substances that, when absorbed

into the body of a living organism, alters

normal bodily function



In pharmacology, a drug is defined

as"a chemical substance used in

the treatment, cure, prevention, or

diagnosis of disease or used tootherwise enhance physical or

mental well-being.

http://en.wikipedia.org/wiki/Pharmacology

http://en.wikipedia.org/wiki/Chemical

http://en.wikipedia.org/wiki/Chemical

http://en.wikipedia.org/wiki/Pharmacology



The major classifications of drugs are as follows

1 Prescription drugs :- Drugs obtained only by the

written prescription of a doctor

2 Over the counter drugs:- Drugs which can be

purchased without the written prescription of adoctor



3 Recreational drugs:- drugs used to help

a person relax or socialize. ex. Alcohol,Tea, Coffee, Tobacco, Chocolate

4 Illicit drugs :- These are drugs prohibited by the authority. These are the most

notorious type of drugs. Generally,

recognized as harmful. All arePSYCHOACTIVE (have the potential to

alter mood or behavior



Mode of Drug Action:

It is important to distinguish betweenactions of drugs and their effects. Actions of

drugs are the biochemical physiological

mechanisms by which the chemical

produces a response in living organisms.



The effect is the observable consequence

of a drug action. For example, the action

of penicillin is to interfere with cell wallsynthesis in bacteria and the effect is the

death of the bacteria.



One major problem of pharmacology is that no

drug produces a single effect. The primary effect

is the desired therapeutic effect. Secondary

effects are all other effects beside the desired

effect which may be either beneficial or harmful.



Drugs are chosen to exploit differencesbetween normal metabolic processes and

any abnormalities which may be present.

Since the differences may not be very

great, drugs may be nonspecific in action

and alter normal functions as well as theundesirable ones. This leads to

undesirable side effects.



The biological effects observed after a

drug has been administered are the resultof an interaction between that chemical

and some part of the organism.

Mechanisms of drug action can be

viewed from different perspectives,

namely, the site of action and the general

nature of the drug-cell interaction.



l. Killing Foreign Organisms:

Chemotherapeutic agents act by killingor weakening foreign organisms such as

bacteria, worms, viruses.

The main principle of action is selective

toxicity, i.e. the drug must be more toxic

to the parasite than to the host.



2. Stimulation and Depression:

Drugs act by stimulating or depressingnormal physiological functions.

Stimulation increases the rate ofactivity while depression reduces the

rate of activity



Drug use and drug abuse:-



When drugs are used to treat an illness,

prevent a disease and improve health

condition, it is termed drug use.



Intake of drugs for reasons otherthan medical in a manner that affects

physical or mental functioning is

termed drug abuse.



Antibiotics:- Antibiotics are substanceproduced by microorganism which has

the capacity of inhibiting the growth

and even destroying other micro

organism .

Examples : Penicillines, Ciphalosporin,Chlorumphenicol,Tetracyclin etc



Penicillins are first introduced in

1940 Alexander Fleming .

These are bactericidal and inhibit

cell wall synthesis in bacteria, kill

a wide variety of them.

The basic structure in penicillin

contains β lactum ring and are

called β lactum

Examples: Penicilline-G , Amoxycilline , AmpicillineExamples: Penicilline-G , Amoxycilline , Ampicilline



Examples: Penicilline-G , Amoxycilline

, Ampicilline



Examples: Penicilline-G , Amoxycilline , Ampicilline

Mechanism of action of Antibiotics:-

Penicillins enter the bacteria via the cellwall. Inside the cell, they bind to

penicillin-binding protein.

Once bound, normal cell wall synthesis is

disrupted. As a result: bacteria cells die

from cell distruction.



Uses of anti biotics: For the Preventionand treatment of infections caused by

susceptible bacteria, such as: gram-

positive bacteria -Streptococcus,Enterococcus, Staphylococcus species



Misuse of Anti biotic and its consequences :- The widespread

use of antibiotics both inside and outside of medicine is playing a significant role in the emergence of resistant

bacteria. Antibiotic resistance is a specific type of drug

resistance when a microorganism has the ability of

withstanding the effects of antibiotics.



Antibiotic resistance evolves via natural selection

acting upon random mutation.

The volume of antibiotic prescribed is the major factor

in increasing rates or bacterial resistance rather than

compliance with antibiotics.

Inappropriate prescribing of antibiotics has been

attributed to a number of causes including: people whoinsist on antibiotics



What is antibiotic misuse:-

Taking antibiotics when they are not neededeg; for viral infections.

When needed, taking antibiotics incorrectly:

Stopping the medicine when you feel better –

Not finishing the prescription,saving

antibiotics for a future illness and sharing or

using someone else’s medicine



Following care shall be taken to prevent the misuse of anti biotics

•Antibiotics should only be taken at your doctor’sprescription.

•To ensure that the infection is totally under control,

confirm the number of days of treatment regimen

with your doctor or pharmacist and complete the

whole course accordingly.



•If you miss one dose, take it as soon as you

remember but never take a double dose.

•Complete the whole course by following doctor’s

prescription to take antibiotics on the right time at the

right dose.



SULPHA DRUGS(sulphonamides):-

Sulfonamides are synthetic antimicrobial

agents with a wide spectrum encompassing

most gram-positive and many gram-negative

organisms.

These drugs were the first efficient treatment tobe employed systematically for the prevention

and cure of bacterial infections



Classifications of sulphonamides

Sulphonamides may be classified

broadly on the basis of their site of

action as

i)S lh id f l i f ti



i)Suplhonamide for general infections:-

These are invareobly employed against the

streptococcal, meningococcal , gonococcal,andpneumococcal infections .

Examples : Sulfanilamide, sulphapyredene,sulpha thiazole,sulfadiazine etc.

ii) Sulpphonamides for urenary infections:-

Examples:- Sulfacetamide,sulfafurazole etc

iii)Sulphonamides for intestenal infection:- Examples:- Sulfaguanidene, pthalyl sulfathiazole etc



iv)Sulphonamide for local infections:- Examples:- sulfacetamide sodium,Mafenide etc

iii)Sulphonamides for intestenalinfection:-

Examples:- Sulfaguanidene, pthalylsulfathiazole etc

iv)Sulphonamide for local infections:-

Examples:- sulfacetamide

sodium,Mafenide etc



MODE OF ACTION OF SULPHONAMIDESSulphanomides are bacteriostatic in

nature.However in large doses they may also act as

bactericidal.

Sulphanomide sensitive microorganism require p-aminobenzoic acid(PABA),for the synthesis of folic

acid,which is essential for the synthesis of DNA and

RNA and there for for the growth and multiplication

of bacteria..



Sulphanomides can compete withPABA and prevent the utilization of

PABA and thereby the synthesis of

bacterial DNA and RNA,

Thus the sulphanomides have

selective effect on the sensitivebacteria



ANALGESICS AND ANTI INFLAMMATORY

AGENTS:

Anti inflammatory agents are drugs used to diminish

or reduce inflammations and pain arising from it.

Non narcotic analgesic differ from narcotic analgesic

in the way that they do not depress the CNS(central

nervous system) and are devoid of addiction liability



General mode of action:-

Prostaglandins play an important role in radiating pain ,fever and inflammation

Antipyretics , Analgesics and Anti-inflammatory effects of

drugs are due to inhibition of synthesis and release of

prostaglandins.

Release of prostaglandin is reduced by stablilsing the cell

membrane and the synthesis is reduced by blocking theenzyme prostaglandin synthetase



Examples and uses of antipyretics , analgesics and anti-

inflammatory agents

Asprin:- Used as antipyretic, Antirheumatic and antithrombolytic

agent

Paracetamol (Aceteminophen):- Used as antipyretic and mild

analgesic

Analgin(Novalgin):- Used to relieve mild to moderate pain



Mefenamic acid:- Used in the relief of headache, tooth ache, muscular pain and stomach

pain

Ibuprofen:- Used to relief muscular pain, toothache and joint pain.

Diclofenac:- Used in the treatment of

rheumatoid arthritis,spondylitis and acutemusculoskeletal disorders



ANTI HISTAMINES:

A histamine antagonist (commonly called anantihistamine) is a pharmaceutical drug that inhibits

the action of histamine by blocking it from attaching

to histamine receptors; or it may inhibit the

enzymatic activity of histidine decarboxylase,catalyzing the transformation of histidine into

histamine (atypical antihistaminics).

H1 antagonists are commonly referred to as

antihistamines.



Antihistamines are commonly used for the

relief of allergies caused by intolerance of

proteins. Itching and sneezing are

suppressed by antihistamine blocking of H1-

receptors on nasal sensory nerves

Eg:- Chlorpheniramine, Cetirizine, Cyclizine,Brompheniramine.



Tranquilizers:-

Tranquilizers are central nervous systemdepressant drugs classified as sedative-

hypnotics.

Tranquilizers are classified into two main

categories: minor tranquilizers (anxiolytics, or

anti-anxiety agents) and major tranquilizers

(neuroleptics), drugs used to treat severe

mental illnesses



. Minor tranquilizers are used in the treatment of

anxiety, tension, panic attacks, and insomnia.

Neuroleptics specifically relieve the symptoms of

mental illness, but are also used as sedatives

before surgical and medical procedures; they are

rarely misused for other purposes.



Minor tranquilizers are, however, frequentlyabused.

Minor tranquilizers may include Valium (diazepam),

Librium/Novopoxide (chlordiazepoxide), Halcion

(triazolam), ProSom (estazolam), Xanax, and Ativan



How do tranquilizers work? At therapeutic doses,

tranquilizers generally relieve anxiety and may in

some people induce a loss of inhibition and afeeling of well-being.

Many tranquilizers tend to induce sleep. As the

dose of the tranquilizer is increased, so are the

degree of sedation and the impairment of mentalacuity and physical coordination.



NARCOTICS:-Narcotics are addictive drugs that reduce the

user's perception of pain and induceeuphoria (a feeling of exaggerated and

unrealistic well-being).





Narcotics are central nervous system depressants.

These drugs often induce a state of euphoria orfeeling of extreme well-being, and they are

powerfully addictive.

The body quickly builds a tolerance to narcotics in as

little as two to three days, so that greater doses are

required to achieve the same effect



. Because of the addictive qualities of these

drugs, most countries in the twenty-first

century have strict laws regarding theproduction and distribution of narcotics

Examples include morphine, codeine,

heroin, methadone etc



How Narcotics Work:-

The central nervous system in humans and other

mammals contains five different types of opioid

receptor proteins, located primarily in the brain,

spinal cord, and digestive tract.



When a person takes an opioid medication, the

drug attaches to these opioid receptors in thebrain and spinal cord and decreases the person's

perception of pain. Narcotics do not, however,

reduce or eliminate the cause of the pain.



Some of the opioid receptors (known as mu and sigma

receptors) influence a person's perception of pleasure.

When a narcotic medication stimulates these receptor

proteins, the person typically experiences intense

sensations of euphoria or well-being.



The speed with which these drugs take effect depends

on the method of administration; IV narcotics reach

their peak effectiveness within ten minutes, while oralnarcotics take about an hour and a half, and skin

patches take between two and four hours.



General Use of Narcotics:

Narcotics have several legitimate uses:

NarcoticAnalgesic: Doctors frequently prescribe oral

codeine and propoxyphene (alone or in combination with

aspirin) for pain control after oral surgery, for severe

menstrual cramps, and for temporary pain relief after other

outpatient surgical procedures.

Intravenous narcotics may be given for several days after

major surgery to relieve the patient's discomfort..



Subsequent methods of administering opioids

following surgery include a sustained-release

injected form of morphine sulfate (DepoMorphine)and a patient-controlled transdermal system (E-

TRANS) that releases doses of fentanyl when the

patient pushes a button attached to the arm or

upper chest.

Intravenous narcotics may also be used forpalliative care, to relieve the pain of patients

diagnosed with terminal cancer



Antitussive: Antitussives are medications

given to control coughing. Codeine is often

effective in relieving severe coughs and is acommon ingredient in prescription cough

mixtures



Antidiarrheal: Paregoric, a liquid preparation

containing powdered opium, anise oil, andglycerin, is sometimes prescribed for severe

diarrhea.

The opium in paregoric works to control

diarrhea because it slows down the rhythmic

contractions of the intestines that ordinarily

move food through the digestive tract.



Lomotil, another antidiarrheal

medication, contains a synthetic opioid

known as diphenoxylate; it is oftenrecommended for treating cancer

patients with diarrhea caused by

radiation therapy.



Disinfectants and Antiseptics:-

Disinfection may be defined as: Cleaning an article of someor all of the pathogenic organisms which may cause

infection. Perfect disinfectant would also offer complete and

full sterilization, without harming other forms of life, be

inexpensive, and non-corrosive.

Disinfectants are used on inanimate objects in contrast toantiseptics, which are used on living tissue. Eg;- Phenolics

as Amyl phenol, Hypochlorates etc

A ti ti



Antiseptics:

Antiseptics are Agents used on theskin and mucous membranes to kill

microorganisms and are not for use on

inanimate objects.

Eg: Chlorhexidene, Iodene,Betadene

etc .













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