Talk to us?

- NEETMDS- courses
NEET MDS Lessons
Pharmacology

Nitrous Oxide (N2O)

MAC 100%, blood/gas solubility ratio 0.47
- An inorganic gas., low solubility in blood, but greater solubility than N2
- Inflammable, but does support combustion.
- Excreted primarily unchanged through the lungs.
- It provides amnesia and analgesia when administered alone.
- Does not produce muscular relaxation.
- Less depressant to both the cardiovascular system and respiratory system than most of the other inhalational anesthetics.
- Lack of potency and tendency to produce anoxia are its primary limitations.
- The major benefit of nitrous oxide is its ability to reduce the amount of the secondary anesthetic agent that is necessary to reach a specified level of anesthesia.

Adverse effects 

Nitrates 
– Headache, hypotension, dizziness, lightheadedness, tachycardia, palpitations 

Beta-adrenergic blocking agents
– hypotension, bradycardia, bronchospasm, congestive heart failure 

Calcium channel blockers 
– hypotension, dizziness, lightheadedness, weakness, peripheral edema, headache, congestive heart failure, pulmonary edema, nausea, and constipation 

Drugs that increase effects of Antianginal drugs 
• Antihypertensive 
• Diuretics 
• Phenothiazine antipsychotic agents
• Cimetidine 
• Digoxin 

Drugs that decrease effects of Antianginal
• Adrenergic drugs - epinephrine 
• Anticholinergic 
• Calcium salts 
• Phenobarbital, Phenytoin

Adjunctive Antianginal Drugs

In addition to antianginal drugs, several other drugs may be used to control risk factors and prevent progression of myocardial ischemia to myocardial infarction and sudden cardiac death.

These may include:
• Aspirin. This drug has become the standard of care because of its antiplatelet (ie, antithrombotic) effects. Recommended doses vary from 81 mg daily to 325 mg daily or every other day; apparently all doses are beneficial in reducing the possibility of myocardial reinfarction, stroke, and death. Clopidogrel 75 mg/day,
Is an acceptable alternative for individuals with aspirin allergy.

• Antilipemics. These drugs may be needed by clients who are unable to lower serum cholesterol levels sufficiently with a low-fat diet. Lovastatin or a related “statin” is often used. The goal is usually to reduce the serum cholesterol level below 200 mg/dL and lowdensitylipoprotein cholesterol to below 
130 mg/dL.

• Antihypertensives. These drugs may be needed for clients with hypertension. Because beta blockers and calcium channel blockers are used to manage hypertension as well as angina, one of these drugs may be effective for both disorders.

Sedative-Hypnotic Drugs

Sedative drug is the drug that reduce anxiety (anxiolytic) and produce sedation and referred to as minor tranquillisers. 

Hypnotic drug is the drug that induce sleep


Effects: make you sleepy; general CNS depressants

Uses: sedative-hypnotic (insomnia ), anxiolytic (anxiety, panic, obsessive compulsive, phobias), muscle relaxant (spasticity, dystonias), anticonvulsant (absence, status epilepticus, generalized seizures—rapid tolerance develops), others (pre-operative medication and endoscopic procedures,  withdrawal from chronic use of ethanol or other CNS depressants)

1- For panic disorder alprazolam is effective.

2- muscle disorder: (reduction of muscle tone and coordination) diazepam is useful in treatment of skeletal muscle spasm e.g. muscle strain and spasticity of degenerative muscle diseases.

3-epilepsy: by increasing seizure threshold.

Clonazepam is useful in chronic treatment of epilepsy while diazepam is drug of choice in status epilepticus.

4-sleep disorder: Three BDZs are effective hypnotic agents; long acting flurazepam, intermediate acting temazepam and short
acting triazolam. They decrease the time taken to get to sleep They increase the total duration of sleep

5-control of alcohol withdrawals symptoms include diazepam, chlordiazepoxide, clorazepate and oxazepam.

6-in anesthesia: as preanesthetic amnesic agent (also in cardioversion) and as a component of balanced anesthesia

Flurazepam significantly reduce both sleep induction time and numbers of awakenings and increase duration of sleep and little rebound insomnia. It may cause daytime sedation.

Temazepam useful in patients who experience frequent awakening, peak sedative effect occur 2-3 hr. after an oral dose.

Triazolam used to induce sleep in recurring insomnia and in individuals have difficulty in going to sleep, tolerance develop within few days and withdrawals result in rebound insomnia therefore the drug used intermittently.


Drugs and their actions

1. Benzodiazepines: enhance the effect of gamma aminobutyric acid (GABA) at GABA receptors on chloride channels. This increases chloride channel conductance in the brain (GABA A A receptors are ion channel receptors).

2. Barbiturates: enhance the effect of GABA on the chloride channel but also increase chloride channel conductance independently of GABA, especially at high doses 

3. Zolpidem and zaleplon: work in a similar manner to benzodiazepines but do so only at the benzodiazepine (BZ1) receptor type. (Both BZ1and BZ2 are located on chloride channels.)

4. Chloral hydrate: probably similar action to barbiturates.

5. Buspirone: partial agonist at a specific serotonin receptor (5-HT1A).

6. Other sedatives (e.g., mephenesin, meprobamate, methocarbamol, carisoprodol, cyclobenzaprine): 
mechanisms not well-described. Several mechanisms may be involved.

7. Baclofen: stimulates GABA linked to the G protein, Gi , resulting in an increase in K + conductance and a decrease in Ca2+ conductance. (Other drugs mentioned above do not bind to the GABA B receptor.) 

8. Antihistamines (e.g., diphenhydramine): block H1 histamine receptors. Doing so in the CNS leads to sedation.

9. Ethyl alcohol: its several actions include a likely effect on the chloride channel.

Amoxicillin

a moderate-spectrum

β-lactam antibiotic used to treat bacterial infections caused by susceptible

Mode of action Amoxicillin acts by inhibiting the synthesis of bacterial cell walls. It inhibits cross-linkage between the linear peptidoglycan polymer chains that make up a major component of the cell wall of Gram-positive bacteria. microorganisms. It is usually the drug of choice within the class because it is better absorbed, following oral administration, than other beta-lactam antibiotics. Amoxicillin is susceptible to degradation by  β-lactamase-producing bacteria, and so is often given clavulanic acid.

Microbiology Amoxicillin is a moderate-spectrum antibiotic active against a wide range of Gram-positive, and a limited range of Gram-negative organisms

Susceptible Gram-positive organisms : Streptococcus spp., Diplococcus pneumoniae, non β-lactamase-producing Staphylococcus spp., and Streptococcus faecalis.

Susceptible Gram-negative organisms  Haemophilus influenzae, Neisseria gonorrhoeae, Neisseria meningitidis, Escherichia coli, Proteus mirabilis and Salmonella spp.

Resistant organisms Penicillinase producing organisms, particularly penicillinase producing Staphylococcus spp. Penicillinase-producing N. gonorrhoeae and H. influenzae are also resistant

All strains of Pseudomonas spp., Klebsiella spp., Enterobacter spp., indole-positive

Proteus spp., Serratia marcescens, and Citrobacter spp. are resistant.

The incidence of β-lactamase-producing resistant organisms, including E. coli, appears to be increasing.

Amoxicillin and Clavulanic acid Amoxicillin is sometimes combined with clavulanic acid, a β-lactamase inhibitor, to increase the spectrum of action against

Gram-negative organisms, and to overcome bacterial antibiotic resistance mediated through β-lactamase production.

Glitazones (thiazolidinediones)

Thiazolidinediones, also known as the "-glitazones"

pioglitazone
rosiglitazone

Mechanism

bind to nuclear receptors involved in transcription of genes mediating insulin sensitivity
peroxisome proliferator-activating receptors (PPARs)

↑ insulin sensitivity in peripheral tissue
↓ gluconeogenesis
↑ insulin receptor numbers
↓ triglycerides

Clinical use

type II DM
as monotherapy or in combination with other agents
contraindicated in CHF
associated with increased risk of MI (in particular rosiglitazone)

Chloral hydrate

1. Short-acting sleep inducer—less risk of “hangover” effect the next day.
2. Little change on REM sleep.
3. Metabolized to trichloroethanol, an active metabolite; further metabolism inactivates the drug.
4. Used for conscious sedation in dentistry.
5. Can result in serious toxicity if the dose is not controlled.

Ciclopirox:Ciclopirox is a synthetic antifungal agent for topical dermatologic use.

Explore by Exams