Chemotherapy

Chemotherapy:
its a term used for the drug treatment of parasitic infections (bacteria, portozoa, viruses, fungi, and helminthes); in which these parasites are destroyed by the drug, but without injury on the host.

Classification: 
 (A) According to causative agents:

1. antibacterial 
2. antifunal
3. antiviral
4. antiprotozoal
5. antihelmentics 

in turn; antibacterial could be classified by their action:

• Bacteriostatics: which inhibit bacterial growth
• bactericidal: kill the bacteria

important note: depending on the dose; the drug could be converted from bacteriostatics to bactericidal; meaning that at high dose at high dose they are converted to bactericidal and in low dose or normal dose they are bacteriostatics.

(B) According to the spectrum of activity: 

1. narrow spectrum
2. extended spectrum 
3. broad spectrum 

General Principles of chemotherapy: 

1. making the diagnosis:  means to know exactly the type of infection, the organism responsible for that & sensitivity testing.
2. removal of the barrier: make it easy for the drug to penetrate and to go to site of infaction
3. decide whether chemotherapy is really necessary: 
4. select the best drug: meaning that the drug should be very specific to the infection; keeping in mined the condition of the immune system of the patient; pregnancy & lactating 
5. the cost: the drug should be very effective and do not cost very much
6. optimum dose and frequency: this done by knowing the pharmacokientics of the drug

Important Problem we could face by using antibiotics:

1. drug resistence 
2. super infection
3. drug-drug interaction
4. adverse effect