Introductory Pharmacology (just paraphrasing words and create fluent answer)

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1. Describe the mechanism of action of propranolol, nifedipine, and an ACE inhibitor in reducing blood pressure in a hypertensive individual.

Reply:-

The high blood pressure if found should be moderated since if allowed to last for a longer period then there remains a possibility of catching cardiac arrest, heart disease and even the probabilities of kidney damage is increased. By use of proper medication blood pressure can be kept under control in person suffering from symptoms if hypertension. There are a number of different pharmaceutical agents that can be used for the treatment of hypertension. Propranolol is one of them that act as a beta blocker and it causes blockade of beta-adrenergic receptors in the heart and several other organs. And drugs are being used very frequently now-a-days owing to the fact of their ability to reduce the chances of heart attack and other serious cardiovascular problems. The ACE or the Angiotensin converting enzyme inhibitors are also novel drugs that can be used to control blood pressure and there is one advantage of using these drugs that they are not thought to cause sexual dysfunction, a problem seen with other antihypertensive. There is considerable number of evidences that goes to show that ACE inhibitors will reduce the incidence of heart disease in patients with high blood pressure more effectively than other blood pressure lowering drugs by means of properly allowing blood to circulate through the veins.

There is another potential drug- nifedipine which is also known as the Calcium channel blocker. It works by lowering down the amount of calcium reaching sites in cells of vascular smooth muscle. This decrease leads to a relaxation of arterioles, a decrease in resistance of the arterioles, and a lowering of blood pressure.

Nifedipine decreases the amount of calcium reaching sites in cells of vascular smooth muscle. This decrease leads to a relaxation of arterioles, a decrease in resistance of the arterioles, and a lowering of blood pressure.

2. How does nitrogylcerin act to reduce angina? Describe the mechanism of action and state why this old drug is still widely used today.

Reply:-

Nitro-glycerine acts in the following manner to cut down the probabilities of encountering angina.

Mechanism of Action

The mechanism of action of organic nitrates has been studied for many years and a great deal of argument has been provoked by proponents of different theories. There is now a general consensus that organic nitrates relax the smooth muscle of blood vessels and exert their therapeutic effect by the following two mechanisms that are known universally.

1. Relaxation of large veins, leading to vasodilation. This effect results in a decrease in venous blood returning to the heart. This results in a decrease in cardiac output, a decrease in heart size, and a decrease in blood pressure. As a result, there is a decrease in energy expenditure and a decrease in the oxygen requirement of the heart.

2. Dilates large coronary arteries. As a result, blood is diverted to areas of the heart with low blood flow. There is, therefore, enhanced oxygen supply to areas of the heart which are deficient in oxygen.

And in this way Nitro-glycerine works to control the probabilities of encountering angina which is a very distressful state of heart of the human body and if it happens usually a deposition of lipid in the coronary arteries takes place causing the sheer hindrance to normal flow of blood which is accompanied with a sudden severe pain in the chest and Nitro-glycerine works really perfect as a novel agent by lowering down the chances of lipid deposition in the internal coronary arteries and so it is widely used.

3. Antibiotic resistance is a common problem in the treatment of infectious diseases. What measures can be taken to reduce the emergence of antibiotic resistant strains of microorganisms.

Reply:-

It is a well accepted fact that problems do arise out of lesser resistances growth from the consumption of antibiotics. Following measures can be adopted on a large degree to mitigate the issue-

1. Formulation of a specific diagnosis:

The physician makes the most intelligent guess on clinical grounds as to which microorganism is responsible for the infection.

2. Specimens taken and sent for laboratory examination:

Prior to administering an antibiotic, the physician will take a blood, urine or saliva specimen, a throat swab, or several of these, to send to a diagnostic laboratory. It is important to take these specimens prior to administering the antibiotic because the presence of the antibiotic in the specimen will increase the difficulty experienced by laboratory personnel in growing and identifying bacteria.

3. Selection of antibiotic most likely to be effective:

This places a heavy onus on the physician. She/he will require to keep up to date with the latest information on newer antibiotics and the changing susceptibility of bacteria to older and new antibiotics.

4. Antimicrobial susceptibility tests:

These tests enable laboratory workers to help the physician select the most effective antibiotic once the microorganism has been isolated and identified.

5. Prophylaxis (prevention) of infection with antibiotics:

Approximately 30-50% of antibiotics are administered to prevent infection. Clinical studies have shown that, in some situations, prophylaxis with antibiotics is highly effective. On the other hand, prophylaxis has been shown to be valueless in some situations and may be harmful. In certain situations, the use of antibiotics for prophylaxis is controversial and further clinical studies are required to resolve the controversies.

4. Describe the conditions where the use of prophylactic vitamins is rational and justified.

Reply:-

The following are some of the severe conditions that require usage of prophylactic vitamins on rotational basis and that should also be done in accordance with the prescribed doe and keeping into consideration the symptoms of the patient in general which will definitely ensure proper usage of vitamins on a rational mode and is most beneficial

1. Inadequate intake:

(a) Individuals who consume an inadequate diet for reasons of poverty and/or geography. A good example is the aboriginal people living in the Canadian north.

(b) Individuals consuming a diet consisting of one major food. An example is black groups in South Africa living on a corn diet.

(d) Individuals who have particular ideas leading to an idiosyncratic diet.

(e) Individuals who, for religious reasons, consume an inadequate diet.

(f) Alcohol-dependent individuals who have an inadequate food intake since they obtain a large number of calories from alcohol.

(g) Individuals on restrictive diets.

(h) Individuals on restricted diets for disease management.

2. Disturbances in absorption:

(a) Prolonged diarrhea.

(b) Liver disease.

(c) An individual taking antibiotics that alter intestinal bacteria. Vitamin K and biotin (one of the vitamin B group) are derived from intestinal bacteria.

3. Increased tissue requirements:

In healthy individuals:

(a) During growth.

(b) During periods of hard physical work, e.g. working deep underground in a gold mine under hot and humid conditions.

(d) Stress.

In illness:

(a) Hyperthyroidism (overactive thyroid).

(b) Fever.

5. Should herbal medicines be considered drugs? In your answer consider both potential benefits and harm from herbals. You may also include ethical, social and economic factors.

Reply:-

Herbal medicines should not be considered as drugs as such since they are of herbal origin and there are some pertinent rationales that can be put up in effect to support this point of view

Benefits of Using Herbal Medication

1. The public has expressed concern over the side effects of allopathic medicines. While most herbal products do not appear to be harmful, a number have significant toxicities, and indeed some herbal products are toxic.

2. The cost of the allopathic medicines, especially newer agents, are high. The public has the perception, probably justified, that herbal drugs are less expensive than allopathic drugs.

3. There is a lack of faith in allopathic drugs. Not all allopathic medicine are effective and a number that are effective have serious toxicities associated with their use. The concept that “what is natural is best” seems to prevail.

Problems associated with usages

1. Lack of efficacy data. Current efficacy is based on empirical evidence, not controlled studies.

2. Lack of data on safety. All drugs should be evaluated for safety.

3. Lack of standardization. Often there is poor quality control. Active ingredient varies in concentration from batch to batch.

4. Undeclared ingredients. The consumer is not assured of the content of the herbal drug.

5. Intentional adulteration. This is the addition of substances other than the herbal. One product had hydrocortisone added, a drug under the Food and Drug Act. Also, dihydroepiandrosterone, heavy metals, cocaine, NSAIDs, and estrogens have been found in some herbals.

6. Source is questionable. There is a lack of control at the source point, e.g. foreign countries. Manufacturing facilities and processes are not inspected.

So, based on all of these pros and cons it can be asserted here that herbal medicines can be considered as drugs provided there is documented evidences of their ability to cure people and definite diagnosis ailments are available.

6. List 10 over the counter drug you would choose for yourself to take on a 2 week canoe trip to Algonquin Park. Give a one sentence justification for each choice.

Reply:-

The following list of 10 over the counter drug I may opt for myself to take on a 2 week canoe trip to Algonquin Park-

(a) Acetylsalicylic acid (ASA)- The compound possesses analgesic (reduces pain), antipyretic (reduces fever), and anti-inflammatory (reduces inflammation) properties. In appropriate doses, the drug is effective for pain, fever and inflammation.

(b) Acetaminophen- Acetaminophen is the drug of choice in cases where ASA causes G.I. irritation and in febrile conditions in children and young adults (acetaminophen is not associated with Reyes syndrome). Acetaminophen is available in a liquid preparation and is convenient for use in children.

(c) Ibuprofen- As an anti-inflammatory, it is probably one of the most efficacious OTC anti-inflammatory agent on the market. The mechanism of action of ibuprofen is a reversible inhibition of the synthesis of prostaglandins.

(d) Naproxen - is an effective analgesic, antipyretic and anti-inflammatory agent. It may well emerge as the most effective OTC anti-inflammatory agent available. It is an inhibitor of prostaglandin synthesis.

(e) Topical analgesics- Most pain is best treated with an internal analgesic

(f) Antihistamines- Most antihistamines have anticholinergic properties (atropine-like) and this may aid in reduction of secretions. Anticholinergics (atropine) decrease nasal and salivary secretions. In terms of efficacy, antihistamines have a very limited role in alleviating the symptoms of a cold.

(g) Decongestants- These compounds are all α-adrenergic receptor stimulants (agonists), and when they activate the α receptor, they cause vasoconstriction and a reduction in congestion.

(h) Cough suppressants- Cough is a complex event involving signals from the bronchioles which are processed by the cough centre in the medulla (a region of the brain). Centrally-acting cough suppressants block the processing of the information in the medulla, hence reducing the frequency of the cough.

(i) Expectorants- Expectorants are substances that stimulate secretions in the bronchial tree and loosen the phlegm in the upper airway passages.

(j) Analgesics- Analgesics are effective in reducing the fever and the achy feeling associated with the cold. Drugs of choice are ASA or acetaminophen; acetaminophen may be a better choice. They are useful for fever and as analgesics.

7. How do chemicals cause cancer? Describe a multi-stage process responsible for chemical carcinogenesis.

Reply:-

In early studies, it was difficult to understand how so many chemicals with no apparent similarity in chemical structure could be carcinogenic. However, advances in our understanding of drug metabolism have helped to clarify the process. Thus, it is now clear that the carcinogens are in general inactive as such but undergo metabolic activation by drug metabolising enzymes in the body. The highly chemically reactive forms, termed the ultimate carcinogens, react irreversibly with a DNA molecule, thus causing a change in the chemistry of the gene. This change is perpetuated in subsequent divisions of the cell in which it occurs; in other words, a mutation has been induced. The genes affected may be oncogenes or tumor suppressor genes. Experimental studies have shown that the cells must divide (cell proliferation) to make the genetic change permanent. There are three different categories of carcinogens – initiators, promoters and progressors. The chemicals described above fit into the first category, namely initiators. These agents damage genes involved in control of cell division and facilitate the division and proliferation of cells. Cancer arises when a single cell accumulates a number of mutations and escapes restraints on cell division. The second category, promoters, does not damage genes but selectively enhance the growth of cancer cells or precursors of cancer cells. Progressors allow the rapid growth of tumors once they are established.

The following multistage method is to test a chemical for carcinogenicity is to determine whether it causes cancer in laboratory animals. Such tests require two to three years to conduct and are very costly to perform.

There is therefore a great interest in the development of cheaper tests. One such test, developed by Bruce Ames of Berkeley, California, employs a mutant of the bacterium Salmonella typhimurium that has lost the ability to make the amino acid, histidine. When this mutant* is maintained in a histidine-free culture medium it cannot grow. However, the mutant bacterium regains the ability to grow when exposed to mutagenic chemicals that repair the original defect. When 174 different known carcinogens were tested by the Ames test, 156 (90%) caused mutations in the bacterial mutant. It was thus deduced that if a chemical causes a mutation in the bacterial system there is a high likelihood that it will be a carcinogen.

8. Anabolic steroids have been used by athletes for the past 60 years. Describe the mechanism of action of an anabolic steroid in enhancing athletic performance.

Reply:-

These are compounds with reduced androgenic effects but maintaining anabolic effects, i.e. the building of muscle mass. Androgenic effect of a compound is the effect on secondary male sex characteristics. Testosterone, the male sex hormone, has both androgenic and anabolic properties. Anabolic steroids are compounds that have reduced androgenic effects compared to testosterone, but this separation is by no means complete.

Anabolic steroids are used by athletes to increase muscle mass and strength in a large variety of sports, including football, weight lifting, running, and gymnastics. In addition, they are used to enhance physical appearance.

It has been assumed that these agents increase muscle mass and strength and produce a more masculine appearance, but early studies failed to show a clear response. Recent studies have demonstrated that anabolic steroids can increase both the size and the strength of the athlete, but not aerobic performance (e.g. long distance running). There are at least three potential mechanisms whereby anabolic steroids produce this effect:

· They produce an anti-catabolic response. As the athlete trains, he/she reaches a plateau or point where more muscle is used as fuel or broken down as is produced in response to training. The athlete trains so hard that he/she uses protein from the muscle to fuel that training. This action is blocked by the anabolic steroids.

· Anabolic effects follow the anti-catabolic effects and the drugs produce new protein. These responses may be more important or have greater effects at the high doses used by athletes.

· Motivational responses also contribute to the overall effect. Anabolic steroids can produce aggressive behaviour, a condition called “roid rage”. This aggressive behaviour is beneficial for most sports, especially football.