NEET MDS Lessons
Pharmacology
ISOPRENALINE
It is beta-receptor stimulant, which stimulates the heart and causes tachycardia.
It relaxes the smooth muscles particularly the bronchial and GIT. It is mainly used in bronchial asthma, in the treatment of shock and as a cardiac stimulant in heart block.
ORCIPRENALINE
Is a potent β-adrenergic agonist.
Receptor sites in the bronchi and bronchioles are more sensitive to the drug than those in the heart and blood vessels.
AMPHETAMINE
increases the systolic and diastolic blood pressure. Amphetamine is a potent CNS stimulant and causes alertness, insomnia, increased concentration, euphoria or dysphoria and increased work capacity.
Amphetamines are drugs of abuse and can produce behavioural abnormalities and can precipitate psychosis.
PHENYLEPHRINE
It is used as a nasal decongestant and mydriatic agent and also in the treatment of paroxysmal supraventricular tachycardia.
UTERINE RELAXANTS (TOCOLYTICS)
ISOXSUPRINE
Isoxsuprine has a potent inhibitory effect on vascular and uterine smooth muscle and has been used in the treatment of dysmenorrhoea, threatened abortion, premature labour and peripheral vascular diseases.
Ketamine
- Causes a dissociative anesthesia.
- Is similar to but less potent than phencyclidine.
- Induces amnesia, analgesia, catalepsy and anesthesia, but does not induce convulsions.
- The principal disadvantage of ketamine is its adverse psychic effects during emergence from anesthesia. These include: hallucinations, changes in mood and body image.
- During anesthesia, many of the protective reflexes are maintained, such as laryngeal, pharyngeal, eyelid and corneal reflexes.
- Muscle relaxation is poor.
- It is not indicated for intracranial operations because it increases cerebrospinal fluid pressure.
- Respiration is well maintained.
- Arterial blood pressure, cardiac output, and heart rate are all elevated.
Ether (diethylether)
Ether (diethylether) MAC 2.0%, Blood/gas solubility ratio 15
- Ether is generally mixed with 3% ethanol to retard oxidation. Peroxides form on exposure to air and can enhance the danger of an explosion.
- Slow rate of induction and recovery due to its high blood/gas solubility ratio.
- Produces profound muscular relaxation.
- Both the rate and the minute volume of ventilation tend to be elevated during the inhalation of ether.
- Ether maintains good circulatory stability and does not sensitize the heart to the arrhythmogenic action of catecholamines.
- More than 90% of the absorbed ether can be recovered unchanged in the expired air. Metabolism is not extensive and the metabolites are not hepatotoxic.
- Ether is a versatile anesthetic of unexcelled safety, but it is flammable and irritating to breathe. Secretions can be blocked with anticholinergics.
Valdecoxib
used in the treatment of osteoarthritis, acute pain conditions, and dysmenorrhoea
Etoricoxib new COX-2 selective inhibitor
ANTIASTHMATIC AGENTS
Classification for antiasthmatic drugs.
I. Bronchodilators
i. Sympathomimetics (adrenergic receptor agonists)
Adrenaline, ephedrine, isoprenaline, orciprenaline, salbutamol, terbutaline, salmeterol, bambuterol
ii. Methylxanthines (theophylline and its derivatives)
Theophylline
Hydroxyethyl theophylline
Theophylline ethanolate of piperazine
iii. Anticholinergics
Atropine methonitrate
Ipratropium bromide
II. Mast cell stabilizer
Sodium cromoglycate
Ketotifen
III. Corticosteroids
Beclomethasone dipropionate
Beclomethasone (200 µg) with salbutamol
IV. Leukotriene pathway inhibitors
Montelukast
Zafirlukast
Ibuprofen
used to relieve the symptoms of arthritis, primary dysmenorrhoea, fever; and as an analgesic, especially where there is an inflammatory component.
Indications
rheumatoid arthritis, osteoarthritis, juvenile rheumatoid arthritis, primary dysmenorrhoea
fever, relief of acute and/or chronic pain states in which there is an inflammatory component
MOA
inhibition of cyclooxygenase (COX); thus inhibiting prostaglandin synthesis.
Antifungal
There are several classes of antifungal drugs.
The polyenes bind with sterols in the fungal cell wall, principally ergosterol. This causes the cell's contents to leak out and the cell dies. Human (and other animal) cells contain cholesterol rather than ergosterol so are much less suceptible.
Nystatin
Amphotericin B
Natamycin
The imidazole and triazole groups of antifungal drugs inhibit the enzyme cytochrome P450 14α-demethylase. This enzyme converts lanosterol to ergosterol, and is required in fungal cell wall synthesis. These drugs also block steroid synthesis in humans.
Imidazoles:
Miconazole
Ketoconazole
Clotrimazole
The triazoles are newer, and are less toxic and more effective:
Fluconazole
Itraconazole
Allylamines inhibit the enzyme squalene epoxidase, another enzyme required for ergosterol synthesis:
Terbinafine
Echinocandins inhibit the synthesis of glucan in the cell wall, probably via the enzyme 1,3-β glucan synthase:
Caspofungin
Micafungin
Others:
Flucytosine is an antimetabolite.
Griseofulvin binds to polymerized microtubules and inhibits fungal mitosis.