Classification

1. Natural Alkaloids of Opium

Phenanthrenes -> morphine, codeine, thebaine

Benzylisoquinolines -> papaverine, noscapine

2. Semi-synthetic Derivatives

diacetylmorphine (heroin) hydromorphone, oxymorphone hydrocodone, oxycodone

3. Synthetic Derivatives

phenylpiperidines pethidine, fentanyl, alfentanyl, sufentnyl

benzmorphans pentazocine, phenazocine, cyclazocine

propionanilides methadone

morphinans levorphanol

Antidiarrheal

 Antidiarrheal drugs may be given to relieve the symptom (non-specific therapy) or may be given to treat the underlying cause of the symptom (specific therapy). 

Ι. Drugs used for the symptomatic (non-specific) treatment of diarrhoea include: 

• Opiates and opiate derivatives are the most effective (such as morphine), but it is not used because of potentially serious adverse effects. Other agents, such as diphenoxylate and loperamide, are commonly used.

• Adsorbent – demulcent products such as kaolin – pectin preparation may be included in antidiarrheal preparations. Unfortunately, they may adsorb nutrients and other drugs, including the antidiarrheal agents if given concurrently.

• Anticholinergic agents e.g. atropine is occasionally used to decrease abdominal cramping and pain associated with diarrhoea.

ΙΙ. Specific therapy may include the use of antibacterial agents that are recommended for use in carefully selected cases of bacterial enteritis. For example, severe diarrhoea by salmonella, shigella, campylobacter and clostridia species can be treated by antibiotics (ampicillin, chloramphenicol, co-trimoxazole). 

Neuron Basic Structure (How brain cells communicate)

• Synapse:A junction between the terminal button of an axon and the membrane of another neuron
• Terminal button(orbouton):The bud at the end of a branch of an axon; forms synapses with another neuron; sends information to that neuron.
• Neurotransmitter:A chemical that is released by a terminal button; has an excitatory or inhibitory effect on another neuron.

Different types of Synapses
1-Axo-denrdritic 
2-Axo-axonal 
3-Axo-somatic

Chemical transmission in the CNS 

The CNS controls the main functions of the body through the action endogenous chemical substances known as “neurotransmitters”.
These neurotransmitters are stored in and secreted by neurons to “transmit”information to the postsynaptic sites producing either excitatoryor inhibitory responses.
Most centrally acting drugs exert their actions at the synaptic junctions by either affecting neurotransmitter synthesis, release, uptake, or by exerting direct agonistor antagonistaction on postsynaptic sites.

Operator position

For the right-handed operator, the 8 and 10 o’clock position and for left-handed operators, the corresponding 2 and 4 o’clock position almost always allows for optimal visualization of the injection field.

GLP-1 analogs

Exenatide

Mechanism

GLP-1 is an incretin released from the small intestine that aids glucose-dependent insulin secretion
basis for drug mechanism is the observation that more insulin secreted with oral glucose load compared to IV 

Exenatide is a GLP-1 agonist

↑ insulin
↓ glucagon release
the class of dipeptidyl peptidase inhibitors ↓ degradation of endogenous GLP-1
e.g.) sitagliptin, -gliptins 
 

Clinical use
type II DM
 

Toxicity
nausea, vomiting
pancreatitis
hypoglycemia
if given with sulfonylureas

Sufentanil

• A synthetic opioid related to fentanyl.
• About 7 times more potent than fentanyl.
• Has a slightly more rapid onset of action than fentanyl.