CENTRAL NERVOUS SYSTEM PHARMACOLOGY

Antipsychotic Drugs

1. Phenothiazines

a. Aliphatic derivatives
(1) Chlorpromaxine
b. Piperidine derivatives
(1) Thioridazine
(2) Mesoridazine
c. Piperazine derivatives
(1) Fluphenazine
(2) Perphenazine
(3) Prochlorperazine
(4) Trifluoperazine

2. Haloperidol resembles the piperazine phenothiazines.

3. Thiothixene resembles the piperazine phenothiazines.

4. Others (e.g., loxapine, pimozide).

5. Newer and more atypical antipsychotic drugs:
a. Clozapine
b. Olanzapine
c. Quetiapine
d. Risperidone
e. Ziprasidone
f. Aripiprazole

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.

A. Drugs
1. Lithium
2. Carbamazepine
3. Valproic acid

Sedative Hypnotics

1. Benzodiazepines
2. Barbiturates
3. Zolpidem and zaleplon
4. Chloral hydrate
5. Buspirone
6. Other sedatives (e.g., mephenesin, meprobamate, methocarbamol, carisoprodol, cyclobenzaprine)
7. Baclofen
8. Antihistamines (e.g., diphenhydramine)
9. Ethyl alcohol

Antiepileptic Drugs

Phenytoin
Carbamazepine
Phenobarbital
Primidone
Gabapentin
Valproic acid
Ethosuximide

Anti-Parkinson Drugs

a. L-dopa plus carbidopa (Sinemet).
b. Bromocriptine, pergolide, pramipexole, ropinirole.
c. Benztropine, trihexyphenidyl, biperiden, procyclidine.
d. Diphenhydramine.
e. Amantadine.
f. Tolcapone and entacapone.
g. Selegiline.
 

Ampicillin offered a broader spectrum of activity than either of the original penicillins and allowed doctors to treat a broader range of both Gram-positive and Gram-negative infections. Ampicillin is often used in molecular biology as a test for the uptake of genes (e.g., by plasmids) by bacteria (e.g., E. coli)

Piroxicam:

Half‐life of 45 hrs. Once‐daily dosing. Delay onset of  action.

High doses inhibits PMN migration, decrease oxygen  radical production, inhibits lymphocyte function. 

used to relieve the symptoms of  arthritis, primary dysmenorrhoea, pyrexia; and as an analgesic,non-selective  cyclooxygenase (COX) inhibitor

The risk of adverse side efects is nearly ten times higher than with other NSAIDs. Peptic ulcer (9.5 higher)

Sulfonylureas

1st generation
tolbutamide
chlorpropamide

2nd generation

glyburide
glimepiride
glipizide

Mechanism

glucose normally triggers insulin release from pancreatic β cells by increasing intracellular ATP
→ closes K+ channels → depolarization → ↑ Ca2+ influx → insulin release

sulfonylureas mimic action of glucose by closing K+ channels in pancreatic β cells 
→ depolarization → ↑ Ca2+ influx → insulin release

its use results in

↓ glucagon release
↑ insulin sensitivity in muscle and liver

Clinical use

type II DM

stimulates release of endogenous insulin 
cannot be used in type I DM due to complete lack of islet function

Toxicity

first generation

disulfiram-like effects
especially chlorpropamide

second generation

hypoglycemia
weight gain

Drugs used to induce vomiting

In case of poisoning with noncorrosive agents, and assuming incomplete absorption of the poison has taken place, induction of vomiting can be carried out. One of the drugs used for this purpose is emetine which causes irritation of the upper gut and, on absorption, it also acts on  CTZ.  

Chemotherapeutic agents (or their metabolites) can directly activate the medullary chemoreceptor trigger zone or vomiting center; several neuroreceptors, including dopamine receptor Type 2 and serotonin Type 3 (5-HT3) from cell damage(GIT and pharynx) play roles in vomiting.

BETA-LACTAM ANTIBIOTICS
β-lactam antibiotics are a broad class of antibiotics including penicillin derivatives, cephalosporins, monobactams, carbapenems and β-lactamase inhibitors; basically any antibiotic agent which contains a β-lactam nucleus in its molecular structure. They are the most widely used group of antibiotics available.

Mode of action All β-lactam antibiotics are bactericidal, and act by inhibiting the synthesis of the peptidoglycan layer of bacterial cell walls.β-lactam antibiotics were mainly active only against Gram-positive bacteria, the development of broad-spectrum β-lactam antibiotics active against various Gram-negative organisms has increased the usefulness of the β-lactam antibiotics.

Common β-lactam antibiotics

Penicillins

Narrow spectrum penicillins:  

benzathine penicillin
benzylpenicillin (penicillin G)
phenoxymethylpenicillin (penicillin V)
procaine penicillin

Narrow spectrum penicillinase-resistant penicillins

methicillin
dicloxacillin
flucloxacillin

Moderate spectrum penicillins : 

amoxicillin, ampicillin

Broad spectrum penicillins :      

co-amoxiclav (amoxycillin+clavulanic acid)

Extended Spectrum Penicillins:    

piperacillin
ticarcillin
azlocillin
carbenicillin