Chemotherapy

Chemotherapy

Chemotherapy is the use of anticancer drugs to treat cancerous cell. Chemotherapy has been used for many years and is one of the most common treatment for cancer. Chemotherapy works by interfering with the cancer cell's ability to grow or reproduce. Different group of drugs work in different ways to fight cancer cell. Chemotherapy is used alone for some types of cancer or in combination with other treatments such as surgery or radiation. A combination of chemotherapy drugs is used to fight a specific cancer. 

Chemotherapy can be administered:

•             As a pill to swallow
•       As an injection into the muscles or tissues.
•       Intravenously (directly to the bloodstream; also called IV).
•      Topically (applied to the skin)
•           Directly into a body cavity

·        There are over 50 chemotherapy drugs that are commonly used. Chemotherapy is the way to cure cancer by killing cell. It kills cancer cell and also can kill normal cell. But killing normal cells can cause some unpleasant side effects. The side effects vary from one drug to another drug and from patient to patient. 

The good news about these side effects is that there are some ways to ease most of the symptoms of this effect. Sometimes, certain side effects can have long lasting or permanent effects. Certain chemotherapy drugs can result in infertility or the inability to father a child which may be permanent. So, it is necessary to talk to doctor about any concerns before starting chemotherapy.

Antimicrobial Agents

Antimicrobial Agents

Mechanism of Action According to classification

Sulfonamide
Most bacteria produce its own folic acid (FA) of which Para Amino Benzoic Acid (PABA) is a constituent. Antimicrobial agents, Sulfonamide has similar structure like PABA. So, by interfering, it inhibits to produce actual folic acid and form an alternate folate which is metabolically injurious to bacteria. 

Example: Sulfadiazine, Para amino salicylic Acid (PAS).

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Beta Lactum Antibiotics
This antimicrobial agents are bactericidal. It interferes with the last step of bacterial cell wall synthesis called transpeptidation by inhibiting the transpeptidase enzyme. So that cross linking does not take place. And resulting in exposure of less stable membrane. Cell lysis can occur then through osmotic pressure.

Example: Penicillin (Pen-G,Pen-V,Amoxicillin), Cephalospirin (Cefazolin, Cefuroxime, Cefixime, Cefepime).

Protein Synthesis inhibitor
Entry of these antimicrobial agents in organism caused by diffusion. The drugs bind to the 30s subunit of bacterial ribosome and blocking the access of amino acyl t-RNA to the m-RNA ribosome complex at the receptor site. And protein synthesis inhibited.

Example: Tetracycline, Doxicycline.

Aminoglycoside: Antimicrobial agents, Aminoglycoside transport through bacterial cell wall by diffusion and cytoplasmic membrane. Then it will bind to ribosome of bacteria, that will result, inhibition of protein synthesis.

Example: Neomycin, Streptomycin.

Macrolide: This antimicrobial agents bind irreversibly to a site on the 50s subunit of the bacterial ribosome, thus inhibiting the translocation steps of protein synthesis. They also interfere transpeptidation.

Example: Azithromycin, Erythromycin, Clarithromycin.

Chloramphenicol: This antimicrobial agents bind to the bacterial 50s ribosomal subunit and inhibits protein synthesis at the peptidyl transferase reaction.

Inhibitor of nucleic acid synthesis & function

Fluoroquinolone: It enters the cell by diffusion through water-fluid protein channel (porin) in outer membrane. Inhibit the replication of bacterial DNA by interfering with action of DNA gyrase during bacterial growth and reproduction. 

Example: Ciprofloxacin, Ofloxacin.

Quinolone: Mechanisn of action is same like  fluoroquinolone, but not fluorinated. Mainly used for gram(-) bacteria, that cause UTI.

Example: Nalidixic Acid.

# Side Effects of Antimicrobial 

Hypertension Drugs

Hypertension Drugs

Mechanism of Action According to Classification

Diuretic: Its a hypertension drugs that reduce BP by increasing Na & H2O excretion. This causes decrease in extracellular volume and resulting decrease in cardiac output and renal blood flow.

Example: Hydrochlorothiazide, Furosamide.

Beta-Blocker: Its a hypertension drugs that reduce Blood pressure (BP) by decreasing cardiac output. It also decreases sympathetic outflow from central nervous system and inhibit release of rennin from the kidney, thus decreasing formation of angiotensin II and secretion of aldosterone.

These drugs also reduce oxygen demand by reducing force and contraction of heart. So, decrease activity of heart, decrease cardiac output and fall BP.

Example: Propanolol, Atenololo.

                                          

Angiotensin Converting Enzyme (Ace) Inhibitor: Its a hypertension drugs that decrease blood pressure by reducing peripheral vascular resistance, except increasing cardiac output, rate or contractility. It blocks the angiotensin converting enzyme (ACE) that cleaves angiotensin I to form potent vasoconstrictor angiotensin II. So, vasodilatation occurs and bradykinin increase. It also decrease the secretion of aldosterone.

Example: Captopril, Ramipril.

Calcium Channel blockers: Calcium play an important role in maintaining the tone of smooth muscle and in contraction of myocardium.Calcium channel blockers are the hypertension drugs that block the inward movement of calcium (to cell) by binding to L-type calcium channel in the heart and in smooth muscle of coronary and peripheral vasculature. These cause the vascular smooth muscle to relax and dilating arterioles.

Example: Verapamil (1^st choise for Anti-arrythmic), Diltiazem (1^st choise for Anti-anginal), Nifedipine (1^st choise for Anti-hypertensive).

Alpha-Blocker: Its a hypertension drugs that decrease the peripheral vascular resistance and lower the arterial BP by causing the relaxation of arterial and venous smooth muscle. Salt & H2O retention occur.

It also blocks the post synaptic alpha adrenergic receptor. So, it inhibits the vasoconstriction produced by the norepinephrin that is released from the synaptic nerve endings. So, vasodilation occurs and lowers the blood pressure.

Example: Doxazosin, Prazosin.

Central Sympatholytics: Its a hypertension drugs that forms false neurotransmitter alpha-methyl nor-adrenaline which combines with alpha-receptor present on the surface of the neurons in the lower brain stems. So, inhibits neurons and decrease central and peripheral sympathetic activities. And finally, decrease blood pressure.

Example: Methyl dopa.

Direct vasodilator: Its a hypertension drugs that dilate resistant vessel, arteriolar dilation occur, decrease peripheral resistance and as a result decrease blood pressure.

Example: Diazoxide.

# Side Effects of Antihypertensive Drug

# Hypertension & its Cause

# Sign and Symptoms of Hypertension