Block 1 Drugs Flashcards
Atropine
Summary:
Atropine is a muscarinic antagonist used to treat poisoning by muscarinic agents, including organophosphates and other drugs.
Blocks the effects of acetylcholine and other choline esters.
Atropine drug class:
Muscarinic cholinergic receptor antagonist
Drug mechanism?
Blocks the effects of acetylcholine at the postganglionic parasympathetic nerve terminals.
Atropine binds to and inhibits muscarinic acetylcholine receptors, competitively blocking the effects of acetylcholine and other choline esters
Indications ( uses) :
In anaesthesia, blocks vagal slowing of the heart and inhibits bronchiole secretion.
To reduce intestinal spasm (e.g. for IBS).
To reduce the tremor in Parkinson’s Disease.
To prevent motion sickness.
To dilate the pupil for opthalmological
To treat bradycardia
Contraindications:
Atropine generally is contraindicated in patients with glaucoma, pyloric stenosis, thyrotoxicosis, fever, urinary tract obstruction and ileus.
Digoxin
Digoxin drug class:
Cardiac glycoside
Sodium potassium ATPase inhibitor
Mechanism:
Inhibits Na/K ATPase
Which means there is more intracellular NA+
Which means there is more intracellular Ca+
Which increases the force of myocardial infraction.
Indication (reason for the drug) :
Heart failure
Supraventricular (above the ventricles) fibrillation
Atrial flutter
Contraindications:
- Recent MI (myocardial infraction)
- thyroid disease
- severe respiratory disease
- hypoxia
- ventricular tachycardia
- myocarditis
Side effects:
arrhythmias
anorexia
nausea
vomiting
diarrhea
intoxication
Fluconazole
Drug class: Fluconazole is a triazole antifungal used to treat various fungal infections including candidiasis.
Indications: 1) Vaginal yeast infections caused by Candida 2) Systemic Candida infections 3) Both esophageal and oropharyngeal candidiasis 4) Cryptococcal meningitis 5) UTI (urinary tract infection) by Candida 6) Peritonitis (inflammation of the peritoneum) caused by Candida
Mechanism: action
Fluconazole is a very selective inhibitor of fungal cytochrome P450 dependent enzyme lanosterol 14-α-demethylase. This enzyme normally works to convert lanosterol to ergosterol, which is necessary for fungal cell wall synthesis.
Rivastigmine
Summary: Rivastigmine is a cholinesterase inhibitor used to treat mild to moderate dementia in Alzheimer’s and Parkinson’s.
Rivastigmine drug class:
cholinesterase inhibitor
Indication (reason):
For the treatment of mild to moderate dementia associated with Parkinson’s disease or of the Alzheimer’s type.
Mechanism of action:
Rivastigmine is a carbamate derivative that is structurally related to physostigmine, but not to donepezil and tacrine.
The anticholinesterase activity of rivastigmine is relatively specific for brain acetylcholinesterase and butyrylcholinesterase compared with those in peripheral tissues.
Contraindications ( reason you cant have):
Cardiac conduction conditions.
Bradyarrhythmia or sick sinus syndrome.
Chronic obstructive pulmonary disease or asthma.
Bleeding ulcer history or risk.
Seizure risk or history.
Patient weight under 50 kg.
Side effects:
Rivastigmine may cause nausea, vomiting, diarrhea, stomach pain, loss of appetite, or weight loss.
Pyridostigmine
Summary:
Pyridostigmine is a cholinesterase inhibitor used for symptomatic treatment of myasthenia gravis and congenital myasthenic syndromes and to reverse neuromuscular blockade by nondepolarizing muscle relaxants.
Pyridostigmine drug class:
Anticholinesterases
Cholinesterase inhibitor
What is an acetylcholinesterase:
acetylcholine is broken down by acetylchlinesterase in 2 steps
- 1) acetylcholine is hydrolysed to free choline and acetylated enzyme.
2) The covalent acetyl-enzyme bond is split with the addition of water.
Pyridostigmine drug mechanism:
Has the same action as acetylcholine, except that the breakdown of the acetyl-enzyme bond is much slower, occupying up the acetylchlinesterase and preventing it from binding to acetylcholine.
Indication (reason): Treatment of Myasthenia gravis.
Contraindications: Asthma, bradycardia, arrythmias, recent MI, epilepsy, hypotension, intestinal or
Side effects: nausea, vomitting,, increased salivation, abdominal cramps.
Name some Inflammatory mediators ?
Prostaglandins
Leukotrines
Nitric Oxide
Bradykinin
HIstamine
Cytokines
Where are prostaglandins and leukotrienes produced?
Phospholipids glycerol chain. The last 20 carbons are called Arachidonic Acid.
Arachidonic acid produces prostaglandins and leukotrienes.
We can categorize prostaglandins into 2 main subtypes, what are the properties of each ?
Type 1:
- Increases inflammation
- Increases pain
- Increases fever
- Increases GIT (gastrointestinal tract) integrity. Helps maintain mucus barrier between stomach and strong HCL.
- Produce Thromboxane (TXA2) which promotes platelet aggregation therefore clotting. – Increases platelet aggregation - this promotes clotting
Type 2:
- Increases inflammation
- Increases pain
- Increases fever
- This type of prostaglandin is in high quantities in synovial fluid. Synovial fluid is found around synovial joints and more synovial fluid will increase inflammation of pain.
- This can lead to rheumatoid arthritis
- Decreases platelet aggregation
Which inflammatory inhibitor do NSAIDs affect ?
Which enzymes do NSAIDs inhibit?
- Prostaglandins
- COX-1
COX-2
Which prostaglandin enzyme does Aspirin inhibit more?
Why do doctors say take Aspirin on a full stomach?
- COX-1
- Aspirin decreases GIT(gastrointestinal tract) integrity. To reduce irritation to the stomach lining you should eat Aspin with a meal.
Give an example of a NSAID that is a COX-2 specific inhibitor ?
CELECOXIB. Its a good COX-2 inhibit because it doesn’t increase patient likeliness of clotting.
Parasympathetic vs Sympathetic nervous system ?
- There are only 2 neurons in the sympathetic and parasympathetic nervous system. These are the preganglionic neuron and the post ganglionic neuron.
SNS ( Thoraco- lumbar) :
- the preganglionic neuron is shorter
- the post ganglionic neuron is longer
- In the SNS the the post ganglionic neuron head lies parallel to the spinal cord and very close to each other. These are called the para-vertebral ganglia or ganglionic chain. So if you stimulate one nerve in the sympathetic nervous system you stimulate the whole SNS. This is why the SNS is known as systemic it is nor restricted to one target organ.
- In the SNS the neurons that exit are at the thoracic or lumbar portion if the spinal cord.
- Cranial nerves 3,7,9 and 10 control parasympathetic innervation.
PNS ( Cranio-Sacral):
- the pre ganglionic neuron is longer
- the post ganglionic neuron is shorter
- In the PNS the neurons exit at either the cranial or sacral region.
Ganglion: nerve cell body that is located outside of the CNS
Pre ganglionic and post ganglionic neuron ?
- The preganglionic neuron always releases the neurotransmitter acetylcholine in both the SNS and PNS. Acetylcholine binds to nicotinic receptors on the post ganglion neuron.
- At the post ganglionic neuron at the
PNS: we release Acetylcholine which binds to m receptors
SNS: we release Adrenaline which binds to beta and alpha receptors
Where is adrenaline released from ?
- Adrenaline is released from the adrenal glands and travels in the blood to stimulate all the sympathetic receptors.
