Pharmacology is the study of drugs and the way they interact with living systems.  Clinical pharmacology is the study of drugs in humans.

A drug is any chemical that can effect living processes.

Therapeutics: the medical use of drugs.

An ideal drug has several important properties.  Three of these properties are of utmost importance: effectiveness, safety and selectivity. 

Effectiveness: This is the most important quality that a drug can have.  Effectiveness refers to the drug's ability to do what it is supposed to do.

Safety:  Although no drug can be totally safe, proper usage can lessen the risks of adverse effects.

Selectivity:  A truly selective drug would have no side effects, and would effect only the body process' for which it is designed and given.  Therefore, there is no such thing as a selective drug.

Pharmacokinetics: The way the body deals with a drug.  Pharmacokinetics is concerned with the processes of absorption, distribution, metabolism and excretion.

Pharmacodynamics:  What a drug does to the body.

Pharmacokinetics and pharmacodynamics are two of the processes that determine how a person will respond to a drug.  Other factors include how a drug is administered (dose, route, and timing of administration), interactions with other drugs, and individual physiological variables (weight, age, function of body systems).

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

Erythromycin

used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including  mycoplasma. It is also used to treat outbreaks of chlamydia, syphilis, and gonorrhea.

Erythromycin is produced from a strain of the actinomyces Saccaropolyspora erythraea, formerly known as Streptomyces erythraeus.

Mechanism of action Erythromycin prevents bacteria from growing, by interfering with their protein synthesis. Erythromycin binds to the subunit 50S of the bacterial ribosome, and thus inhibits the translocation of peptides.

Erythromycin is easily inactivated by gastric acids, therefore all orally administered formulations are given as either enteric coated or as more stable salts or  esters. Erythromycin is very rapidly absorbed, and diffused into most tissues and  phagocytes. Due to the high concentration in phagocytes, erythromycin is actively transported to the site of infection, where during active phagocytosis, large concentrations of erythromycin are released.

Most of erythromycin is metabolised by demethylation in the liver. Its main route elimination route is in the bile, and a small portion in the urine.

Erythromycin's half-life is 1.5 hours.

Side-effects. More serious side-effects, such as reversible deafness are rare. Cholestatic jaundice, Stevens-Johnson syndrome and toxic epidermal necrosis are some other rare side effects that may occur.

Contraindications Earlier case reports on sudden death prompted a study on a large cohort that confirmed a link between erythromycin, ventricular tachycardia and sudden cardiac death in patients also taking drugs that prolong the metabolism of erythromycin (like verapamil or diltiazem)

erythromycin should not be administered in patients using these drugs, or drugs that also prolong the QT time.

Fourth Generation:

These are extended spectrum antibiotics. They are resistant to beta lactamases.

Cefipime

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.

Use of local anesthetics during pregnancy

Local anesthetics (injectable)

Drug                                                   FDA category

Articaine                                             C

Bupivacaine                                        C

Lidocaine                                            B

Mepivacaine                                        C

Prilocaine                                            B

Vasoconstrictors

Epinephrine 1:200,000 or 1:100,000 C (higher doses)

Levonordefrin 1:20,000 Not ranked

Local anesthetics (topical)

Benzocaine                                        C

Lidocaine                                            B