Serotonin or 5-hydroxytryptamine (5-HT)

It is a neurotransmitter, widely distributed in the CNS, beginning in the midbrain and projecting into thalamus, hypothalamus, cerebral cortex, and spinal cord. CNS serotonin is usually an inhibitory neurotransmitter and is associated with mood, the sleep-wake cycle.

Serotonin is thought to produce sleep by inhibiting CNS activity. 

In the blood, 5-HT is present in high concentration in platelets (regulator of platelets function) and also high concentration in intestine

Pharmacological effects:

Smooth muscles. 5-HT stimulates the G.I smooth muscle; it increases the peristaltic movement of intestine.
Serotonin contracts the smooth muscle of bronchi; 

Blood vessels. If serotonin is injected i.v, the blood pressure usually first rises, because of the contraction of large vessels and then falls because of arteriolar dilatation. Serotonin causes aggregation of platelets. 

Specific agonists

- Sumatriptan a selective 5-HT1D used in treatment of acute migraine.
- Buspirone a selective 5-HT1A used in anxiety.
- Ergotamine is a partial agonist used in migraine. It acts on 5-HT1A receptor.

Nonspecific 5-HT receptor agonist

o Dexfenfluramine used as appetite suppressant.

Specific antagonists

o Spiperone (acts on 1A receptor) and
o Methiothepin (acts on 1A, 1B, 1D receptors)

Heroin (diacetyl morphine)

Heroin is synthetically derived from the natural opioid alkaloid morphine

Largely owing to its very rapid onset of action and very short half-life, heroin is a popular drug of abuse

It is most effective when used intravenously

Heroin is rapidly deacetylated to 6-monoacetyl morphine and morphine, both of which are active at the mu opioid receptor

More lipid soluble than morphine and about 2½ times more potent.  It enters the CNS more readily.

Factors affecting onset and duration of action of local anesthetics

pH of tissue

pKa of drug

Time of diffusion from needle tip to nerve

Time of diffusion away from nerve

Nerve morphology

Concentration of drug

Lipid solubility of drug

Kinins
Peptide that are mediated in the inflammation.
Action of kinin:
On CVS: vasodilatation in the kidneys, heart, intestine, skin, and liver. It is 10 times active than histamine as vasodilator.

On exocrine and endocrine glands: kinin modulate the tone of pancreas and salivery glands and help regulate GIT motility, also affect the transport of water and electrolytes, glucose and amino acids through epithelial cell transport.

Ibuprofen

used to relieve the symptoms of arthritis, primary dysmenorrhoea, fever; and as an analgesic, especially where there is an inflammatory component.

Indications

rheumatoid arthritis, osteoarthritis, juvenile rheumatoid arthritis, primary dysmenorrhoea

fever, relief of acute and/or chronic pain states in which there is an inflammatory component

MOA

inhibition of  cyclooxygenase (COX); thus inhibiting prostaglandin synthesis.

ANTIBIOTICS

Chemotherapy: Drugs which inhibit or kill the infecting organism and have no/minimum effect on the recipient.

Antibiotic these are substances produced by microorganisms which suppress the growth of or kill other micro-organisms at very low concentrations.

Anti-microbial Agents: synthetic as well as naturally obtained drugs that attenuate micro-organism.

SYNTHETIC ORGANIC ANTIMICROBIAL DRUGS

Sulfonamides

Trimethoprim-sulfamethoxazole

Quinolones – Ciprofloxacin

ANTIBIOTICS THAT ACT ON THE BACTERIAL CELL WALL

Penicillins

Cephalosporins

Vancomycin

INHIBITORS OF BACTERIAL PROTEIN SYNTHESIS

Aminoglycosides - Gentamicin

Antitubercular Drugs: Isoniazid & Rifampin

Tetracyclines

Chloramphenicol

Macrolides – Erythromycin, Azithromycin

Clindamycin

Mupirocin

Linezolid

 ANTIFUNGAL DRUGS

Polyene Antibiotics (Amphotericin B, Nystatin and Candicidin)

Imidazole and Triazole Antifungal Drugs

Flucytosine

Griseofulvin

ANTIPROTOZOAL DRUGS

Antimalarial Drugs – Quinine, Chloroquine, Primaquine

Other Antiprotozoal Drugs – Metronidazole, Diloxanide, Iodoquinol

 ANTIHELMINTHIC DRUGS

Praziquantel

Mebendazole

Ivermectin

ANTIVIRAL DRUGS

Acyclovir

Ribavirin

Dideoxynucleosides

Protease inhibitors