Propoxyphene

• A methadone analog.Used orally to relieve mild to moderate pain.
• A typical opiate, it does not possess anti-inflammatory or antipyretic actions, but has little or no antitussive activity.
• Cannot be used parenterally because of irritant properties.
• Has a low addiction potential primarily due to its lack of potency as an opiate.
• The most common adverse side effects are:• dizziness, drowsiness, and nausea and vomiting. • these effects are more prominent in ambulatory patients.
• Withdrawal symptoms have occurred in both adults and in neonates following use of the drug by the mother during pregnancy.
• CNS depression is additive with other CNS depressants.

Procaine penicillin Procaine penicillin is a combination of benzylpenicillin with the local anaesthetic agent procaine. This combination is aimed at reducing the pain and discomfort associated with a large intramuscular injection of penicillin.

Indications

respiratory tract infections where compliance with oral treatment is unlikely ,syphilis, cellulitis

 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 

OXYMETAZOLINE
 

It is a directly acting sympathomimetic amine used in symptomatic relief in nasal congestion which increases mucosal secretion.

It is used:
- As a nasal decongestant in allergic rhinitis, with or without the addition of antazoline or sodium chromoglycate. 
- As an ocular decongestant in allergic conjunctivitis.

Compounds like naphazoline and xylometazoline are relatively selective α2 agonists, which on topical application produce local vasoconstriction.

Cells of the Nervous System 

1-Neurons (Nerve Cells):function units of the nervous system by conducting nerve impulses, highly specialized and amitotic. Each has a cell body (soma), one or more dendrites, and a single axon. 
• Cell Body: it has a nucleus with at least one nucleolus and many of the typical cytoplasmic organelles, but lacks centriolesfor cell division. 

• Dendrites:Dendrites and axons are cytoplasmic extensions (or processes), that project from the cell body. They are sometimes referred to as fibers. Dendrites (afferent processes) increase their surface area to receive signals from other neurons, and transmit impulses to the neuron cell body. 

• Axon: There is only one axon (efferent process) that projects from each cell body.        
It carries impulses away from the cell body.

2-Glial cells: do not conduct nerve impulses, but support, nourish, and protect the neurons. They are mitotic, and far more numerous than neurons. 

Astrocyte: A glialcell that provides support for neurons of the CNS, provides nutrients regulates the chemical composition of the extracellularfluid.

• Oligodendrocyte: A type of glialcell in the CNS that forms myelin sheaths.

• Microglia:The smallest glialcells; act as phagocytes (cleaning up debris) and protect the brain from invading microorganisms.

• Schwann cell:A cell in the PNS that is wrapped around a myelinatedaxon, providing one segment of its myelin sheath.

Gastric acid secretion inhibitors (antisecretory drugs):

 HCl is secreted by parietal cells of the gastric mucosa which contain receptors for acetylcholine (muscarinic receptors: MR), histamine (H2R), prostaglandins (PGR) and gastrin (GR) that stimulate the production, except PGs which inhibit gastric acid production.
 
Therefore, antagonists of acetylcholine, histamine and gastrin inhibit gastric acid secretion (antisecretory). On the other hand, inhibitors of PGs biosynthesis such as NSAIDs with reduce cytoprotective mechanisms and thus promote gastric mucosal erosion. Also, the last step in gastric acid secretion from parietal cells involve a pump called H+ -K+-ATPase (proton pump). Drugs that block this pump will inhibit gastric acid secretion. Antisecretory drugs include:

1. Anticholinergic agents such as pirenzepine, dicyclomine, atropine.
2. H2-receptors blocking agents such as Cimetidine, Ranitidine, Famotidine, Nizatidine (the pharmacology of these agents has been discussed previously).
3. Gastrin-receptor blockers such as proglumide.
4. Proton pump inhibitors such as omeprazole, lansoprazole.

Major clinical indications of antisecretory drugs:

• Prevention & treatment of peptic ulcer disease.
• Zollinger Ellison syndrome.
• Reflux esophagitis.