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Pharmacology

Phenytoin (Dilantin): for tonic-clonic and all partial seizures (not effective against absence seizures)


Mechanism: ↓ reactivation of Na channels (↑ refractory period, blocks high frequency cell firing, ↓ spread of seizure activity from focus)


Side effects: ataxia, vertigo, hirsutism (abnormal hair growth), gingival hyperplasia, osteomalacia (altered vitamin D metabolism and ↓ Ca absorption), blood dyscrasias (rare; megaloblastic anemia, etc)


Drug interactions: induces hepatic microsomal enzymes (can ↓ effectiveness of other drugs); binds tightly to plasma proteins and can displace other drugs

Streptomycin

Streptomycin was the first of a class of drugs called aminoglycosides to be discovered, and was the first antibiotic remedy for tuberculosis. It is derived from the actinobacterium Streptomyces griseus.

Streptomycin cannot be given orally, but must be administered by regular intramuscular injection.

Nimesulide

analgesic and  antipyretic properties

Nimesulide is a relatively COX-2 selective, non-steroidal anti-inflammatory drug (NSAID) with analgesic and antipyretic properties. Its approved indications are the treatment of acute pain, the symptomatic treatment of osteoarthritis and primary dysmenorrhoea in adolescents and adults above 12 years old.

Banned - not used

Biguanides

metformin

Mechanism

↓ gluconeogenesis


appears to inhibit complex 1 of respiratory chain

↑ insulin sensitivity
↑ glycolysis
↓ serum glucose levels
↓ postprandial glucose levels

Clinical use

first-line therapy in type II DM

Toxicity

no hypoglycemia
no weight gain
lactic acidosis is most serious side effect 
contraindicated in renal failure 

Quinolone

Quinolones and fluoroquinolones form a group of  broad-spectrum antibiotics. They are derived from nalidixic acid.

Fluoroquinolone antibiotics are highly potent and considered relatively safe.

MOA : Quinolones act by inhibiting the bacterial  DNA gyrase enzyme. This way they inhibit nucleic acid synthesis and act bacteriocidically.

Drugs  :Nalidixic acid, Ciprofloxacin , Levofloxacin,  Norfloxacin ,Ofloxacin,  Moxifloxacin  , Trovafloxacin

Classification

I) Esters

 1. Formed from an aromatic acid and an amino alcohol.

 2. Examples of ester type local anesthetics:

 Procaine

Chloroprocaine

Tetracaine

Cocaine

Benzocaine- topical applications only

2) Amides

 1. Formed from an aromatic amine and an amino acid.

 2. Examples of amide type local anesthetics:

Articaine

Mepivacaine

Bupivacaine

Prilocaine

Etidocaine

Ropivacaine

Lidocaine

Distribution

Three major controlling factors:  

Blood Flow to Tissues:  rarely a limiting factor, except in cases of abscesses and tumors.
Exiting the Vascular System:  Occurs at capillary beds.
- Typical Capillary Beds - drugs pass between cells 
- The Blood-Brain Barrier-  Tight junctions here, so drugs must pass through cells.  Must then be lipid soluble, or have transport system.
- Placenta - Does not constitute an absolute barrier to passage of drugs.  Lipid soluble, nonionized compounds readily pass.  
- Protein Binding:  Albumin is most important plasma protein in this respect.  It always remains in the blood stream, so drugs that are highly protein bound are not free to leave the bloodstream.  Restricts the distribution of drugs, and can be source of drug interactions.

Entering Cells:  some drugs must enter cells to reach sites of action.

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