Eicosanoid compounds

Prostaglandines, Leukotriens and Thromboxanes.

They are produced in minute amounts by all cells except RBCs and they act locally at the same site of synthesis.
These agents have many physiological processes as mediators and modulators of inflammatory reactions.

ANTICHOLINERGIC DRUGS
Blocks the action of Ach on autonomic effectors.

Classification
Natural Alkaloids - Atropine. Hyoscine

Semi-synthetic deriuvatives:- Homatropine, Homatropine methylbromide, Atropine methonitrate.

Synthetic compounds 

(a) Mydriatics - Cyclopentolate. Tropicamide.
(b) Antisecretory - Antispasmodics - Propantha1ine. Oxy-phenonium, Pirenzipine.
c) Antiparkinsonism- Benzotopine, Ethopropazine, Trihexyphenidyl, Procyclidine, Biperiden 
Other drugs with anticholinergic properties • Tricyclic Antidepressants • Phenothiazines • Antihistaminics • Disopyramide

MUSCARINIC RECEPTORS SUBTYPES & ANTAGONISTS 
• M 1 Antagonists – Pirenzepine, Telenzepine, dicyclomine, trihexyphenidyl 
• M 2 Antagonists – Gallamine, methoctramine 
• M 3 Antagonists – Darifenacin, solifenacin, oxybutynin, tolterodine

Pharmacological Actions
CNS - stimulation of medullary centres like vagal. respiratory. vasomotor and inhibition of vestibular excitation and has anti-motion sickness properties.
CVS - tachycardia.
Eye - mydriasis
Smooth muscles - relaxation of the muscles receiving parnsympathetic motor innervation.
Glands - decreased secretion of sweat and salivary glands
Body Temperature - is increased as there is stimulation of  temperature regulating centre.
Respiratory System- Bronchodilatation & decrease in secretions. For COPD or Asthma - antimuscarinic drugs are effective
GIT - Pirenzepine & Telenzepine - decrease gastric secretion with lesser side effects.

Characteristics of Opioid Receptors

mu₁

Agonists : morphine phenylpiperidines

Actions:  analgesia bradycardia sedation

mu₂

Agonists : morphine phenylpiperidines

Actions:  respiratory depression euphoria physical dependence  

delta

Actions:  analgesia-weak,  respiratory depression

kappa

Agonists: ketocyclazocine dynorphin nalbuphine butorphanol

Actions:  analgesia-weak respiratory depression sedation

Sigma

Agonists: pentazocine

Action: dysphoria -delerium hallucinations tachycardia hypertension

epsilon:

Agonists: endorphin

Actions: stress response acupuncture

DIAGNOSIS

Affective disorders:
I. unipolar depression – depression alone
bipolar affective disorder – alternating II. bipolar affective disorder – alternating depression and mania

Diagnosis is based on 

At least five of the following for 2 weeks
I. Depressed mood most of the day
II. Markedly diminished interest or pleasureII. Markedly diminished interest or pleasure
III. Significant weight loss or weight
IV. Insomnia or hypersomnia
V. Psychomotor agitation or retardation
VI. Fatigue or loss of energy
VII. Feelings of worthlessness or excessive guilt
VIII. Diminished ability to think or concentrate, 
IX. Recurrent thoughts of death

Underlying biological basis for depression is a deficiency of the monoamine neurotransmitters  norepinephrine and/or serotonin in the brain.

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

Methadone

Pharmacology and analgesic potency similar to morphine.

• Very effective following oral administration.
• Longer duration of action than morphine due to plasma protein binding (t1/2 approximately 25 hrs).
• Used in methadone maintenance programs for drug addicts and for opiate withdrawal. Opiate withdrawal is more prolonged but is less intense than it is following morphine or heroin.