NEET MDS Lessons
Pharmacology
Examples of calculations of doses of vasoconstrictors
Ratio concentrations represent grams per millilitre
1:100,000 = 0.01 mg/mL or 10 µg/mL
1:200,000 = 0.005 mg/mL or 5 µg/mL
1:50,000 = 0.02 mg/mL or 20 µg/mL
1 cartridge of epinephrine 1:200,000 = 9 µg
1 cartridge of epinephrine 1:100,000 = 18 µg
1 cartridge of epinephrine 1:50,000 = 36 µg
1 cartridge of levonordefrin 1:20,000 = 90 µg
Fourth Generation:
These are extended spectrum antibiotics. They are resistant to beta lactamases.
Cefipime
EPHEDRINE
It act indirectly and directly on α and β receptors. It increases blood pressure both by peripheral vasoconstriction and by increasing the cardiac output. Ephedrine also relaxes the bronchial smooth muscles.
Ephedrine stimulates CNS and produces restlessness, insomnia, anxiety and tremors.
Ephedrine produces mydriasis on local as well as systemic administration.
Ephedrine is useful for the treatment of chronic and moderate type of bronchial asthma, used as nasal decongestant and as a mydriatic without cycloplegia. It is also useful in preventing ventricular asystole in Stokes Adams syndrome.
Isoflurane (Forane) MAC 1.3%, Blood/gas solubility ratio 1.4
- Better muscle relaxation than with the other halogenated anesthetic agents.
- Isoflurane markedly potentiates the action of the neuromuscular blocking agents.
- Produces rapid onset and recovery of anesthesia.
- Does not sensitize the heart to catecholamines.
- Produces respiratory depression, but produces less cardiovascular depression
- than does halothane.
- It has an extremely low degree of metabolism and is apparently relatively
- nontoxic.
SYMPATHOMIMETICS
β2 -agonists are invariably used in the symptomatic treatment of asthma.
Epinephrine and ephedrine are structurally related to the catecholamine norepinephrine, a neurotransmitter of the adrenergic nervous system
Some of the important β 2 agonists like salmeterol, terbutaline and salbutamol are invariably used as bronchodilators both oral as well as
aerosol inhalants
SALBUTAMOL
It is highly selective β2 -adrenergic stimulant h-aving a prominent bronchodilator action.
It has poor cardiac action compared to isoprenaline.
TERBUTALINE
It is highly selective β2 agonist similar to salbutamol, useful by oral as well as inhalational route.
SALMETEROL
Salmeterol is long-acting analogue of salbutamol
BAMBUTEROL
It is a latest selective adrenergic β2 agonist with long plasma half life and given once daily in a dose of 10-20 mg orally.
METHYLXANTHINES (THEOPHYLLINE AND ITS DERIVATIVES)
THEOPHYLLINE
Theophylline has two distinct action:
smooth muscle relaxation (i.e. bronchodilatation) and suppression of the response of the airways to stimuli (i.e. non-bronchodilator prophylactic effects).
ANTICHOLINERGICS
Anticholinergics, like atropine and its derivative ipratropium bromide block cholinergic pathways that cause airway constriction.
MAST CELL STABILIZERS
SODIUM CROMOGLYCATE
It inhibits degranulation of mast cells by trigger stimuli.
It also inhibits the release of various asthma provoking mediators e.g. histamine, leukotrienes, platelet activating factor (PAF) and interleukins (IL’s) from mast cell
KETOTIFEN
It is a cromolyn analogue. It is an antihistaminic (H1 antagonist) and probably inhibits airway inflammation induced by platelet activating factor (PAF) in primate.
It is not a bronchodilator. It is used in asthma and symptomatic relief in atopic dermatitis, rhinitis, conjunctivitis and urticaria.
LEUKOTRIENE PATHWAY INHIBITORS
MONTELUKAST
It is a cysteinyl leukotriene receptor antagonist indicated for the management of persistent asthma.
Ketoconazole
synthetic antifungal drug
used for infections such as athlete's foot, ringworm, candidiasis (yeast infection or thrush), jock itch.
Ketoconazole is used to treat eumycetoma, the fungal form of mycetoma.
MOA: Ketoconazole is imidazole structured, and interferes with the fungal synthesis of ergosterol, the main constituent of cell membranes, as well as certain enzymes. It is specific for fungi, as mammalian cell membranes contain no ergosterol.
Sensitive fungi Ketoconazole inhibits growth of dermatophytes and yeast species (such as Candida albicans).
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.