Wednesday, February 23, 2011

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Blogger: Pharmacology and effect of Drugs - Publish Status

Blogger: Pharmacology and effect of Drugs - Publish Status

Role of vitamin B12 and folate

Vitamin B12(cobalamin) deficiency associated neuropathy, originally called subacute combined degeneration, is particularly common in the elderly. The potential danger today is that with supplementation with folic acid of diatary staples such as flour, that the incidence of the disease could rise as folic acid, as opposed to natural folate(N5CH3HFGlu1), enters the cell and the metabolic cycle by a cobalamin independent pathway. This describes the clinical presentation of the disease, which unless treated will induce permanent CNS danage. The biochemical basis of the interrelationship between folate and cobalmin is the maintenance of the two function, nucleic acid synthesis and the methylation reactions. The latter is particularly important in the brain and relies especially on maintaining the concentration of s-adenosylmethionine(SAM) which, inturn, maintains the methylation reaction whose inhibition is considered to cause cobalmin deficiency associated neuropathy. SAM mediated methylation reaction are inhibited by its product s-adenosylhomocysteine(SAH). This occurs when cobalmin is deficient and, as a result, methionine synthesis is inhibeted causing a rise of both homocysteine and SAH. Other potential pathogenic processes related to the toxic effect of homocysteine are direct damage to the vascular endothelium and inhibition of N-methyl-D-aspartate receptors.

Saturday, February 19, 2011

Proton Pump Inhibitor (Omeprazole)

Omeprazole is the prototype member of a new class of substitued benzimidazoles which inhibit the final common step in gastric acid secretion. The only significant pharmacological action of omeprazole is dose dependent suppression of gastric acid secretion; without anticholinergic or H2 blocking action. It is a powerful inhibitor of gastric acid: can totally abolish Hcl secretion, both resting as well as that stimulated by any of the secretagogues, without much effect on pepsin, intrinsic factor, juice volume and gastric motility.



Omeprazole is inactive at neutral pH, but at pH <5 rearrange to two charged cationic forms that react covalently with the SH groups of the H+ K+ ATPase enzyme and inactivate it irreversibly, specially when two molecules of omeprazole react with one molecule of the enzyme. Pharmacology

The oral absorption of omeprazole is ~50%, but as the gastric pH rises a higher fraction(upto 3/4) may be absorbed. It is highly plasma protein bound, rapidly metabolised in liver(plsma half life t1/2 is ~1 hour) and metabolites excreted in urine.

No dose modification is required in elderly or in renal impairment. Because of tight binding to its target enzyme- it can be detected in the gastric mucosa long after its disappearance from plasma. As such, inhibition of Hcl secretion occurs within 1 hour, reaches maximum at 2 hour, is still half maximal at 24 hour and lasts 3 days.

Side effects

Because of marked and long lasting acid suppression, compensatory hypergastrinemia has been observed. This has been found to induce proliferation of parietal cells and gastric carcinoid tumours in rats, but not in human beings. However, it may appear prudent to be apprehensive of prolonged hypergastrinemia and if possible avoid long term use of proton pump inhibitors.

Dose

20 mg OD or BD for one or two weeks

Liv.52

One of the World most enduring phytomedicine, accredited with more than 250 studies and exported to more than 50 contries. Liv.52 restores the metabolic efficience of the liver.



Indication

- In infective hepatitis
- Alcohol-induced liver damage
- IN drug-induced hepatitis
- In cirrhotic condition
- In jaundice and anorexia during pregnancy

Dose:
10-15 ml twice or three times daily

Good Bowel Movements-The starts to Good Morning

HERBOLAX


Herbolax( products from Himalaya health care) is best in chronic constipation for,

- Softens stools and enhance intestinal motility.
- Assure smooth evacuation without colicky pain.
- Does not distureb the fluid-electrolyte balence.
- Does not cause dependence- safe for long term use.

Dose: 2-3 Capsule or tablets before dinner with warm water.

Helicobactor Pylori

Helicobactor pylori is a gram negative bacillus uniquely adapted to survival in the hostile environment of stomach. They attaches to the surface epithelium beneth of the mucus, has high urease activity- produce ammonia, which maintains a neutral microenvironment to bacteria and promotes back diffusion of H+ ions.



H. pylori infection starts with a neutrophilic gastritis lasting 7-10 days, which is usually asymptomatic. Once established, H. pylori generally persists for the life of the host, upto 90% patients of duodenal and gastric ulcer, have tested positive for H. pylori.

Anti-helicobactor pylori

Anti- microbials that have been found clinically effective against H. pylori are: Amoxycillin, Clarithromycin, tetracycline and metronidazole. However, any single drugs is relatively ineffective. Resistance develops rapidly.

Dose:

One week regimens

1. Amoxycillin 500mg TDS/Clarithromycin 250mg BD +metronidazole 400mg TDS+Omeprazole 20mg BD
2. Amoxycillin 500mg TDS+Clarithromycin 250mg TDS + Omeprazole 20mg BD.

Two week regimens

1. Clarithromycin 500mg TDS/Amoxycillin 750 mg BD+ Omeprazole 20mg BD
2. Amoxycillin 500mg TDS/Tetracycline 500mg QID+ Metronidazole 400mg QID+Bismuth 120mg QID.
3. Amoxycillin 750mg TDS+ metronidazole 500mg TDS + Ranitidine 300mg OD.

The regimens are complex and expensive, compliance is poor and side effects are frequent. A comparative examination of all the literature between 1990-1995 relating to H. pylori therapy has suggested that triple therapy that is :

Omeprazole 20 mg + Clarithromycin 500mg + Tinidazole 1000mg per, day for 7 days has high eradication rate (>90%), less side effect( 7%) and required less number of total tablets. However, Amoxycillin can be substituted for clarithromycin with similar benefits.

Thursday, February 17, 2011

Stress, Anxiety and Depression

Researchers estimate that 80-90 % of the illness have stress as the major cause. Following are few tips to prevent the effects of stress.



1. Have food that has low fat content and more proteins and vitamins: this helps to reduce mental stress to a great extent; avoid junk food.


2. Exercise regularly to alleviate stress.

3. Involve yourself in social activities.

4. Laughter serves to be a good medicine to heal stress. it releases endorphins, which make you feel good and serves as antistress hormones.

5. Aromatherapy serves as another stress release technique, which includes the inhalation of scented candles.

6. Massage, warm water bath, and drinking warm milk reduce stress and muscle tension.

Wednesday, February 16, 2011

Diabetes Mellitus

Diabetes mellitus

The term Diabetes mellitus describes a metabolic disorde of multiple etiology characterized by chronic hyperglycemia with disturbance of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action, or both.

Types of Diabetes mellitus

A. Type 1 Diabetes mellitus

This is formerly known as insulin-dependent diabetes mellitus ( IDDM ), Characterized by hyperglycemia due to an absolute deficiency of insulin. Usually caused by autoimmune destruction of the beta cells of the pancreas, with the presence of certain antibodies in blood. A complex disease caused by mutations in more than one gene, as well as by environmental factors.

Patients require lifelong insulin injections for survival in this case. This type of dianetes mellitus is usually develops in childreen and adolescents (although can occur later in life ). This may present with severe symptoms such as coma or ketoacidosis. Patients are usually not obese with this type of diabetes, but obesity is not incompatible with diagnosis. Patients are at increased risk of developing microvascular and macrovascular complication.

B. Type 2 Diabetes mellitus

This is generally called non-insulin-dependent diabetes mellitus ( NIDDM ), Charecterized by hyperglycemia due to defect in insulin secretion . Usually with a contribution from insulin resistance. Patients usually do not require lifelong insulin but can control blood glucose with diet and exercise alone, or in combination with oral medications, or with the addition of insulin. This type of diabetes is usually develops in adult people, related to obesity, decreased physical activity and unhealthy diets.This occurs more frequently in individuals with hypertension, dyslipidemia (abnormal cholesterol profile), and central obesity, and is a component of "metabolic syndrome".

Note:

Gestational diabetes

This is charecterized by hyperglycemia of varying severity diagnosed during pregnancy ( without previously known diabetes) and usually resolving within 6 weeks of delivery. In this case risk to pregnancy itself including congenital malformations, and increased birth weight and an elevated risk of perinatal mortality,and increased risk to women of developimg Type 2 diabetes later in life.

Tuesday, February 15, 2011

Tinnitus

Tinnitus can arise in any of the following areas: the outer ear, the middle ear, the inner ear, or by abnormalities in the brain. Some tinnitus or head noise is normal. If one goes into a sound proof booth and normal outside noise is diminished, one becomes aware of these normal sounds. We are usually not aware of these normal body sounds, because outside noise masks them. Anything, such as ear wac or a foreign body in the external ear, that blocks these background sounds will cause us to be more aware of our own head sounds. Fluid, infection, or disease of the middle ear bones or ear drum (tympanic membrane) can also cause tinnitus.

One of the most common causes of tinnitus is damage to the microscopic endings of the hearing nerve in the inner ear. Advancing age is generally accompanied by a certain amount of hearing nerve impairment, and consequently chronic tinnitus.




Tinnitus, (pronounced tih-NIGHT-us or TIN-ih-tus) is a ringing, swishing, or other type of noise that seems to originate in the ear or head. Most of us will experience tinnitus or sounds in the ears at some time or another. According to the National Institute on Deafness and Other Communication Disorders (NIDCD), almost 12 percent of men who are 65 to 74 years of age are affected by tinnitus. Tinnitus is identified more frequently in white individuals, and the prevalence of tinnitus in the U.S. is almost twice as frequent in the South as in the Northeast.
Tinnitus can be extremely disturbing to people who have it. In many cases it is not a serious problem, but rather a nuisance that may go away. However, some people with tinnitus may require medical or surgical treatment. Twelve million Americans have tinnitus, and one million experience it so severely it interferes with their daily activities.
Tinnitus can arise in any of the four sections of the hearing system: the outer ear, the middle ear, the inner ear, and the brain. Some tinnitus or "head noise" is normal. A number of techniques and treatments may be of help, depending on the cause.
Some of the most common include a sound of crickets or roaring, buzzing, hissing, whistling, and high-pitched ringing.

Other types of tinnitus include a clicking or pulsatile tinnitus (the noise accompanies your heartbeat).

The most common type of tinnitus is known as subjective tinnitus, meaning that you hear a sound but it cannot be heard by others.

A much more uncommon sort is called objective tinnitus, meaning your doctor may sometimes actually hear a sound when he or she is carefully listening for it.

Exams and Tests
Initial evaluation will include a complete history and physical examination of the head and neck including the various nerves in the area.
A complete hearing test (audiogram) will also be performed. Depending on the type of tinnitus, either a special audiogram known as an auditory brainstem response (ABR) or a brain scan such as a computerized tomography (CT) scan or magnetic resonance imaging (MRI) may also be required.
In some cases, your blood pressure and possibly some blood tests for hyperthyroidism may be taken. In very rare instances, a spinal tap may be performed to measure the fluid pressure in the skull and spinal cord.

Tinnitus Treatment

Self-Care at Home
Most cases of tinnitus should be evaluated by an ear, nose, and throat physician before home treatment begins to be sure that the tinnitus is not caused by another treatable problem.


Medical Treatment
Treatment for tinnitus depends on the underlying cause of the problem.
In the majority of cases, tinnitus is caused by damage to the hearing organ. In these cases, there is normally no need for treatment other than reassurance that the tinnitus is not being caused by another treatable illness.
In the very rare instance where the tinnitus is extremely bothersome, there are a number of treatment options.
Some of the most helpful include antianxiety or antidepressant medication and sometimes maskers-small devices like hearing aids that help to block out the sound of the tinnitus with "white noise."
For people who are bothered by tinnitus only when trying to sleep, the sound of a fan, radio, or white noise machine is usually all that is required to relieve the problem.
Most people with tinnitus find that their symptoms are worse when under stress, so relaxation techniques can be helpful.
Avoiding caffeine is advised, as it may worsen symptoms.

Biofeedback may help or diminish tinnitus in some patients.

Avoid aspirin or aspirin products in large quantities
Hearing loss worsens the effect of tinnitus, so protection of hearing and avoiding loud noises is very important in preventing worsening of the symptoms.
In cases where the tinnitus is caused by one of the other rare problems (such as a tumor or aneurysm), treatment of the tinnitus involves fixing the main issue. Although this does not always resolve the tinnitus, some people note relief of their symptoms. Only a very few cases of tinnitus are caused by identifiable, repairable medical conditions.

Prevention
The only real prevention for tinnitus is to avoid damaging your hearing. Most causes other than hearing loss do not have prevention strategies.
According to the American Tinnitus Association, there are several things you can do to protect yourself from excessive noise-related tinnitus:
Protect your hearing at work. Your work place should follow Occupational Safety & Health Administration (OSHA) regulations. Wear ear plugs or earmuffs and follow hearing conservation guidelines set by your employer.

When around any noise that bothers your ears (a concert, sporting event, hunting) wear hearing protection or reduce noise levels.

Even everyday noises such as blow drying your hair or using a lawnmower can require protection. Keep ear plugs or earmuffs handy for these activities.

When to Seek Medical Care
Most newly noticed tinnitus should be evaluated by a physician. Because tinnitus is usually a symptom of something else, if it begins suddenly, see your doctor. This is particularly important if the tinnitus is only heard on one side.
Although the majority of cases of tinnitus are not caused by any acute problems, certain symptoms need to be evaluated to determine whether or not a more serious medical condition is causing the symptoms.
Any time that tinnitus comes on suddenly, particularly in one ear or is associated with hearing loss, seek an immediate evaluation. Sudden hearing loss is often accompanied by tinnitus, and there are medications that may help to restore that hearing. Also certain types of tumors can cause sudden hearing loss and tinnitus that warrant an evaluation.
Tinnitus that is pulsatile (in rhythm with your heartbeat) and comes on suddenly should also be checked relatively rapidly. In very rare instances, this sort of tinnitus can develop because of an aneurysm (a bulging of the wall of a blood vessel) near the ear or because of the sudden onset of very high blood pressure.
Any time tinnitus is noticed in association with changes in personality, difficulty speaking or walking, or with any other movement problem, you should be evaluated for the possibility of a stroke.
Tinnitus Symptoms

With tinnitus, you hear a noise that no one around you hears. This noise is usually a buzzing or ringing type sound, but it may be a clicking or rushing sound that goes along with your heartbeat. The sound is sometimes accompanied by hearing loss and dizziness in a syndrome known as Meniere's disease.

EBASTINE

Introduction

Ebastine is a piperidine derivative,is non sedating anti-histamine. Eastine is 4-dipheylmethoxy-1-(3-(4-terbutylbezoyl)
propyl),long-acting, second generation, selective H1-receptor inverse agonist.

Ebastine has a chemical strcture which is different from other second generation anti-histamine. After over 18 years of use in more than 80 countries around the globe, the efficacy and safety of ebastine has been extensively demonstrated.

Small studies have found beneficial effect in patients suffering from allergic dermatitis, cold urticaria, atopic asthma, Mosquito bite, and the common cold.

Pharmacological action

Ebastine is a long-acting and selective H1-histamine receptor antagonist. After repeated administration, inhibition of peripheral receptor remains at a constant level. Ebastine is rapidly absorbed and undergoes extensive first pass metabolism following oral administration. Ebastine is almost tottly converted to the pharmacologically active acid metabolite, carebastine. Peak plasma level of the metabolites(80ng to 100ng/ml) occr within two to four hours. Food incresese the plasma level of carebastine 1.5-2.0 fold. Half life is in between 15-19 hours. Ebastine and carebastine are highly protein bound(>95%).

Indication

Allergic rhinitis ( Seasonal and perennial) whether or not associated with allergic conjunctivitis. Idiopathic chronic urticaria.

Adverse effect

Headache, dry mouth and drowsiness. Rearely abdominal pain, dyspepsia, asthenia, pharyngitis, epitaxis, sinusitis, nausea and insomnia may occurs.

Contra-indication

Patients with a known hypersensitivity to ebastine or any of it’s ingredients . The safety of eastine during pregnancy and lactation has not been established.

Interaction

Ebastine does not interact with the kinetics of the theophylline, warfarin, cimetidine, diazepam and alcohol. The sedation effect of alcohol and diazepam may be enhanced.

Interaction with ketoconazole or erythromycin increases QTc level.

Dose

Allergic rhinitis : 10 mg to 20 mg daily.
Urticaria : 10 mg daily.

In patients with mild to moderate hepatic impairment should not take more than 10 mg per day.

Warning

Exercise caution when using ebastine in patients with known long QT syndrome, hypokalamia, treatment with any drug known to produce an increases in QT intervals or inhibits CYP3A4 enzyme system such as azole antifungals and microlide antibiotics, moderate to severe hepatic and or renal impairement.