NEET MDS Lessons
Pharmacology
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
Etomidate -Intravenous Anesthetics
- A nonbarbiturate anesthetic used primarily to induce surgical anesthesia.
- It does not produce analgesia.
- Etomidate has minimal effect on the cardiovascular system and respiration during induction of anesthesia.
- Like the barbiturates, etomidate decreases cerebral blood flow, cerebral metabolic rate and intracranial pressure.
- No changes in hepatic, renal or hematologic function have been reported.
- Myoclonic muscle movements are relatively common.
- Postoperative nausea and vomiting are more common with etomidate than with barbiturates.
PHARYNGEAL DEMULCENTS
Administered in the form of lozenges, cough drops and cough linctus.
Produce soothing action on throat directly and by increasing the flow of saliva and provide symptomatic relief from dry cough.
EXPECTORANT
Expectorants are the drugs which increase the production of bronchial secretion and reduce its viscosity to facilitate its removal by coughing.
ANTITUSSIVES
They are central cough suppressants and act centrally to raise the threshold of cough centre and inhibit the cough reflex by suppressing the coordinating cough centre in the medulla oblongata.
Codeine - it depresses cough centre but is less constipating and abuse liability is low.
Pholcodeine is similar to codeine in efficacy and is longer acting. It has no analgesic or addicting property.
Noscapine is another opium alkaloid of benzylisoquinoline group. It is used as antitussive with no analgesic and drug abuse or drug dependence property.
Dextromethorphan is a synthetic compound and its dextroisomer is used as antitussive and is as effective as codeine
Pipazethate is another synthetic compound of phenothiazine category used as antitussive with little analgesic and sedative properties.
ANTIHISTAMINICS
They do not act on cough centre but provide relief due to their sedative and anticholinergic action.
BRONCHODILATORS
Bronchodilators are helpful in individuals with cough and bronchoconstriction due to bronchial hyperreactivity. They help by improving the effectiveness of cough in clearing secretions.
OXYMETAZOLINE
It is a directly acting sympathomimetic amine used in symptomatic relief in nasal congestion which increases mucosal secretion.
It is used:
- As a nasal decongestant in allergic rhinitis, with or without the addition of antazoline or sodium chromoglycate.
- As an ocular decongestant in allergic conjunctivitis.
Compounds like naphazoline and xylometazoline are relatively selective α2 agonists, which on topical application produce local vasoconstriction.
Balanced Anesthesia
A barbiturate, narcotic analgesic agent, neuromuscular blocking agent, nitrous oxide and one of the more potent inhalation anesthetic.
Third Generation Cephalosporins
Prototype drugs are CEFOTAXIME (IV) and CEFIXIME (oral). CEFTAZIDIME (for Pseudomonas aeruginosa.).
Further expansion of Gm negative spectrum to include hard to treat organisms such as Enterobacter, Serratia, and Pseudomonas.
In addition to better Gm negative spectrum, this group has improved pharmacokinetic properties (longer half-lives) that allow once daily dosing with some agents. In general, activity toward Gm + bacteria is reduced. These are specialty antibiotics that should be reserved for specific uses.
Enterobacteriaciae that are almost always sensitive (>95% sensitive)
E. coli
Proteus mirabilis (indole –)
Proteus vulgaris (indole +)
Klebsiella pneumoniae
Gram negative bacilli that are generally sensitive (>75% sensitive)
Morganella morganii
Providencia retgerri
Citrobacter freundii
Serratia marcescens
Pseudomonas aeruginosa (Ceftazidime only)
Gram negative bacilli that are sometimes sensitive (<75% sensitive)
Enterobacter
Stenotrophomonas (Xanthomonas) maltophilia (Cefoperazone & Ceftazidime only)
Acinetobacter
--> cefepime & cefpirome are promising for these bacteria
Bacteria that are resistant
Listeria monocytogenes
Pseudomonas cepacia
Enterococcus sp.
Uses
1. Gram negative septicemia & other serious Gm – infections
2. Pseudomonas aeruginosa infections (Ceftazidime - 90% effective)
3. Gram negative meningitis - Cefotaxime, Ceftriaxone, Cefepime. For empiric therapy add vancomycin ± rifampin to cover resistant Strep. pneumoniae
4. Gonorrhea - Single shot of Ceftriaxone is drug of choice. Oral cefixime and ceftibuten are also OK.
5. Complicated urinary tract infections, pyelonephritis
6. Osteomyelitis - Ceftriaxone in home health care situations
7. Lyme disease - ceftriaxone in home health care situations
Methods of general anesthesia
CIRCLE SYSTEM
*HIGH-FLOW
FRESH GAS FLOW > 3 l/min.
*LOW-FLOW
FGF ok. 1l/min.
*MINIMAL-FLOW
FGF ok. 0,5 l/min.