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Pharmacology

Eicosanoid compounds

Prostaglandines, Leukotriens and Thromboxanes.

They are produced in minute amounts by all cells except RBCs and they act locally at the same site of synthesis.
These agents have many physiological processes as mediators and modulators of inflammatory reactions.

Needle selection

Nerve blocks:

Inferior alveolar- 25 G short (LLU technique)

PSA- 25 G short

Mental/Incisive- 25 G short

Palatal- 27/30 G short/ultrashort

Gow-Gates/Akinosi- 25 G long

Infraorbital- 25 G long

Field Block:

ASA 25/27 short

Infiltration:

Infiltration/SP 25/27 short

PDL/Intraosseous

PDL 27/30 short

Intraosseous 30 short/ultrashort

SULPHONAMIDES

Derivative of  sulphonilamide (Para-amino Benzene (PABA ) sulphonamide).

Anti-bacterial spectrum

Bacteriostatic to gram + and gram - bacteria. but bactericidal concentrations arce attained in urine. S pyogencs. H influenzae.E coli, few- Staph aureus. gonococci. pneumococci, proteus, shigella and Lymphogranuloma venereum.

Mechanism of action

Inhibits bacterial folate synthetase as they compete with PABA

Less soluble in acid urine and may precipitate to cause crystalluria.

Accumulate in patients with renal failure and can cause toxicity

Classification

Shart Acting (4-8 Hrs) sulphadiazine, sulphamethizole.

Intermediate acting(8-16 Hrs): sulphamethoxazole , sulphaphenazole

Long Acting(l-7days): sulphamethoxypyridazine.

Ultralong Acting(3-8days): sulfaline

Adverse effects

I. nausea, vomiting and epigastric pain

2. crystalluria

3. hypersensitivity-like polyarthritis nodosa. Steven-Johnson Syndrome. photosenstivity

4.hemolysis in G-6PD deficiency

5. kernicterus

They inhibit metabolism of phenytoin. tolbutamide. methotrexate

Therapeutic Use

UTI Meningitis, Streptococcal pharyngitis, Bacillary Dysentery

Antidiarrheal

 Antidiarrheal drugs may be given to relieve the symptom (non-specific therapy) or may be given to treat the underlying cause of the symptom (specific therapy). 


Ι. Drugs used for the symptomatic (non-specific) treatment of diarrhoea include: 


• Opiates and opiate derivatives are the most effective (such as morphine), but it is not used because of potentially serious adverse effects. Other agents, such as diphenoxylate and loperamide, are commonly used.

• Adsorbent – demulcent products such as kaolin – pectin preparation may be included in antidiarrheal preparations. Unfortunately, they may adsorb nutrients and other drugs, including the antidiarrheal agents if given concurrently.

• Anticholinergic agents e.g. atropine is occasionally used to decrease abdominal cramping and pain associated with diarrhoea.

ΙΙ. Specific therapy may include the use of antibacterial agents that are recommended for use in carefully selected cases of bacterial enteritis. For example, severe diarrhoea by salmonella, shigella, campylobacter and clostridia species can be treated by antibiotics (ampicillin, chloramphenicol, co-trimoxazole). 

Aquaretics
An aquaretic is a class of drug that is used to promote aquaresis, the excretion of water without electrolyte loss.

Lithium, demeclocycline

Mechanism of Action

1.    Block ADH action on distal tubule and collecting duct. Blocking ADH decreases H2O permeability. H2O is not recovered (distal tubule) using osmotic draw of counter-current multiplier so aquaretics reduce water reabsorption (tubule to blood stream). 
2.    Net effect is an increase in free water clearance
 

 Beta - Adrenergic Blocking Agents 
 
 Mechanisms of Action  
 
- Initial decrease in cardiac output, followed by reduction in peripheral vascular resistance. 
- Other actions include decrease plasma renin activity, resetting of baroreceptors,  release of vasodilator prostaglandins, and blockade of prejunctional beta-receptors.  

Advantages 

- Documented reduction in cardiovascular morbidity and mortality. 
- Cardioprotection: primary and secondary prevention against coronary artery events (i.e. ischemia, infarction, arrhythmias, death). 
- Relatively not expensive. 

Considerations 

- Beta blockers are used with caution in patients with bronchospasm. 
- Contraindicated in more than grade I AV, heart block. 
- Do not discontinue abruptly. 

 Side Effects
- Bronchospasm and obstructive airway disease. 
- Bradycardia  
- Metabolic effects (raise triglyerides levels and decrease HDL cholesterol; may worsen insulin sensitivity and cause glucose intolerance). Increased incidence of diabetes mellitus.  
- Coldness of extremities.  
- Fatigue. 
- Mask symptoms of hypoglycemia. 
- Impotence. 

Indications 

- First line treatment for hypertension as an alternative to diuretics. 
- Hypertension associated with coronary artery disease.
- Hyperkinetic circulation and high cardiac output hypertension (e.g., young hypertensives). 
- Hypertension associated with supraventricular tachycardia, migraine, essential tremors, or hypertrophic cardiomyopathy. 

Beta adrenergic blocker Drugs

Atenolol 25-100
Metoprolol 50-200 
Bisoprolol 2.5-10 

Antidepressant Drugs

Drug treatment of depression is based on increasing serotonin (5-HT) or NE (or both) at synapses in selective tracts in the brain. This can be accomplished by different mechanisms.

Treatment takes several weeks to reach full clinical efficacy.

1. Tricyclic antidepressants (TCAs)
a. Amitriptyline
b. Desipramine
c. Doxepin
d. Imipramine
e. Protriptyline

2. Selective serotonin reuptake inhibitors (SSRIs)
a. Fluoxetine
b. Paroxetine
c. Sertraline
d. Fluvoxamine
e. Citalopram

3. Monoamine oxidase inhibitors (MAOIs)
a. Tranylcypromine
b. Phenelzine

4. Miscellaneous antidepressants

a. Bupropion
b. Maprotiline
c. Mirtazapine
d. Trazodone
e. St. John’s Wort

Antimania Drugs

These drugs are used to treat manic-depressive illness.

1. Lithium
2. Carbamazepine
3. Valproic acid

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