Monday, 24 June 2013

TOP TEN DRUG DISCOVERIES

DRUG DISCOVERY
As till now we all know drug discovery is a procedure to develop new drugs . it is consist of various steps these steps are fully described in my post NEW DRUG DISCOVERY . The drug discovery  showed us various advancement ,there were failures also but we will discuss them later. As we talk about top ten drug discoveries they can be given as follows :
Penicillin  was discovered by Alexander Fleming .Penicillin was the first antibiotic to be used clinically in 1941 . It is a miracle that the' least toxic drug of its kind was the first to be discovered.It was originally obtained from the fungus Penicillium notatum, but the present source is ahigh yielding mutant of P. chrysogenum  When Alexander Fleming stumbled upon penicillin in the 1930s it was one of the biggest discoveries in the healthcare industry and at the time it was dubbed a ‘miracle drug.’ An antibiotic mould which could fight bacterial infections, penicillin is considered to be one of the most powerful antibiotics available and as soon as it reached the mass market it was saving lives. Previous to its discovery, deaths were caused from a simple graze or sore throat as doctors had no way to treat the infections. Penicillin meant that infections were no longer fatal and Fleming  along with Howard Florey and Ernst Chain who took penicillin to market, were awarded a Nobel Prize in 1945. It proved to be the starting point for a range of antibiotics and today remains as one of the most widely used. 
structure of penicillin

mechanism of action of penicillin

Lipitor  A product of global pharmaceutical company Pfizer, cholesterol-lowering drug Lipitor is the best selling treatment in the world. It is currently at the centre of fairly intense media coverage, as Pfizer will lose its exclusive patent rights to the drug in May 2012, seeing it face competition from drug makers who will be able to produce cheaper, unbranded versions of Lipitor.it is described in my previous post  LIPITOR :DRUG THAT MADE HISTORY

Anesthetics A key medical advance for surgical operations, when a number of doctors discovered it was possible to create a reversible loss of sensation surgeons were able to operate without patients feeling any pain. This allowed for more intricate procedures to take place and saved lives as previous to the discovery, many people chose death over the pain of surgery.anesthetics are of two types which can be given as :

  • general anesthetics
  • local anesthetics


General  Anaesthetics
Local Anaesthetics
Site of action
CNS
PNS
Area involved
Whole body
Restricted area
Consciousness
Lost
Unaltered
Poor health patient
Risky
Safer
Non cooperative patient
Possible
Not possible
Major surjery
Preferred
Cannot be used
Minor surgery
Not preferred
preferred

Oral contraceptives A massively popular drug discovery, it is estimated over 100 million women worldwide take oral contraceptive pills. It is one of the first drugs to be taken for an extensive period of time by ‘healthy’ people. This then paved the way for the development of drugs that prevented conditions rather than treating them . the oral contaceptive can be given as .
Combined pill It contains an estrogen and a progestin. With accumulated experience, it has  been possible to reduce the amount of estrogen and progestin in the 'second generation' OC pills without compromising efficacy, but reducing side effects and complications. 'Third generation' pills containing newer progestins like desogestrel with improved profile of action have been introduced in the 1990s. 
Phased regimens These have been introduced to permit reduction in total steroid dose without compromising efficacy. These are biphasic or triphasic. The estrogen dose is kept constant (or varied slightly between 30-40 pg), while the amount of progestin is low in the first phase and progressively higher in the second and third phases. Phasic pills are particularly recommended for women over 35 years of age or when other risk factors are present.
Mini Pill (progestin only pill) It has been devised to eliminate the estrogen, because many of the long-term risks have been ascribed to this component. A low-dose progestin only pill is taken daily continuously without any gap. The menstrual cycle tends to become irregular and ovulation occurs in 20-30% women

Insulin Before the development of insulin, diabetes was a feared illness and diagnosis came with a warning of almost certain death. The 1920’s discovery of the insulin hormone enabled diabetes sufferers to live relatively normal lives by balancing blood sugar levels. Dr Frederick Banting and Professor John Macleod were awarded a Nobel Peace Prize for their discovery and Banting was also awarded a knighthood.
structure of insulin
mechanism of action of insulin

Prozac  After being introduced to the US healthcare sector in 1988 it only took two years for Prozac to achieve its ‘most widely prescribed antidepressant  status, an accolade it still retains today.
It was also one of the first selective serotonin reuptake inhibitor antidepressants and by 1999 25 percent of Eli Lilly’s revenue, the manufacturer of Prozac, was coming from the drug’s sales.

Viagra Another product courtesy of Pfizer, the matter of who exactly invented Viagra is cloudy, with the company saying “hundreds” of people were involved in making the popular aphrodisiac.
In 2000 Viagra accounted for over 90 percent of erectile dysfunction treatments, but this has since dropped dramatically after reports of adverse side effects such as deafness and blindness.Sildenafil's popularity with young adults has increased over the years. Sildenafil's trade name "Viagra" is widely recognized in popular culture, and the drug's association with treating erectile dysfunction has led to its recreational use.The reasons behind such use include the belief that the drug increases libido, improves sexual performance, or permanently increases penis size. Studies on the effects of viagra when used recreationally are limited, but suggest that it has little effect when used by those not suffering from erectile dysfunction. In one study, a 25 mg dose was shown to cause no significant change in erectile quality, but did reduce the post-ejaculatory refractory time.

mechanism of action of  viagra
Aspirin Aspirin was patented in 1990, after a Bayer employee rediscovered a French Chemist’s pain relief formula.
structure of aspirin
It was sold as a powder until 1915 when aspirin tablets were manufactured. As well as now being one of the main ingredients in a number of pain relief remedies, it is thought aspirin can prevent heart attacks, certain types of cancer and lower blood pressure. Aspirin also has an antiplatelet effect by inhibiting the production of thromboxane, which under normal circumstances binds platelet molecules together to create a patch over damaged walls of blood vessels
mechanism of action of aspirin

Morphine Named after Morpheus the Greek god of dreams for its ability to cause drowsiness, the painkiller Morphine was first sold commercially by Merck in 1827.
structure of morphine
The use of morphine intensified after the introduction of the hypodermic syringe in the 1850s and today it is estimated approximately 230 tonnes of the drug are used every year.The euphoria, comprehensive alleviation of distress and therefore all aspects of suffering, promotion of sociability and empathy, "body high", and anxiolysis provided by narcotic drugs including the opioids can cause the use of high doses in the absence of pain for a protracted period, which can impart a morbid craving for the drug in the user. Being the prototype of the entire opioid class of drugs means that morphine has properties that may lend it to misuse. Morphine addiction is the model upon which the current perception of addiction is based.
mechanism of action

Botox Manufactured by Allergan, although Botox has been around for years it is only fairly recently been used on a mass scale.
structure of bacterium clostridium
Botox was first approved by the FDA in 1989 initially to treat muscle spasms in the eye. It has gone on to gain popularity across the world as a cosmetic surgery able to banish wrinkles as well as treating medical conditions such as extreme sweating.Botulinum toxin is a protein and neurotoxin produced by the bacterium Clostridium botulinum. It is the most acutely toxic substance known, with an estimated human median lethal dose of 1.3–2.1 ng/kg intravenously or intramuscularly and 10–13 ng/kg when inhaled.The cosmetic effect of BTX-A on wrinkles was originally documented by a plastic surgeon from Sacramento, California, Dr. Richard Clark, and published in the journal Plastic and Reconstructive Surgery in 1989.Canadian husband and wife ophthalmologist and dermatologist physicians, JD and JA Carruthers, were the first to publish a study on BTX-A for the treatment of glabellar frown lines in 1992.
mechanism of action of botox
Similar effects had reportedly been observed by a number of independent groups (Brin, and the Columbia University group under Dr. Monte Keen. After formal trials, on April 12, 2002, the FDA announced regulatory approval of botulinum toxin type A (Botox Cosmetic) to temporarily improve the appearance of moderate-to-severe frown lines between the eyebrows In cosmetic applications, a Botox injection, consisting of a small dose of botulinum toxin, can be used to prevent development of wrinkles by paralyzing facial muscles.