NEET MDS Lessons
Pharmacology
CLASSICATION OF ANTICOAGULANT DRUGS
1. Direct Acting Anticoagulants
a) Calcium Chelators (sodium citrate, EDTA)
b) Heparin
2. Indirect Acting Anticoagulant Drugs
a) Warfarin
Miconazole
Miconazole is an imidazole antifungal agent commonly used in topical sprays, creams and ointments applied to the skin to cure fungal infections such as Athlete's foot and Jock itch. It may also be used internally to treat vaginal yeast infection.
When used by a person taking the anticoagulant medication warfarin, Miconazole may cause an adverse reaction which can lead to excessive bleeding or bruising.
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
Procaine penicillin Procaine penicillin is a combination of benzylpenicillin with the local anaesthetic agent procaine. This combination is aimed at reducing the pain and discomfort associated with a large intramuscular injection of penicillin.
Indications
respiratory tract infections where compliance with oral treatment is unlikely ,syphilis, cellulitis
Gentamicin
Gentamicin is a aminoglycoside antibiotic, and can treat many different types of bacterial infections, particularly Gram-negative infection.
Gentamicin works by binding to a site on the bacterial ribosome, causing the genetic code to be misread.
Like all aminoglycosides, gentamicin does not pass the gastro-intestinal tract, so it can only be given intravenously or intramuscularly.
Gentamicin can cause deafness or a loss of equilibrioception in genetically susceptible individuals. These individuals have a normally harmless mutation in their DNA, that allows the gentamicin to affect their cells. The cells of the ear are particularly sensitive to this.
Gentamicin can also be highly nephrotoxic, particularly if multiple doses accumulate over a course of treatment. For this reason gentamicin is usually dosed by body weight. Various formulae exist for calculating gentamicin dosage. Also serum levels of gentamicin are monitored during treatment.
E. Coli has shown some resistance to Gentamicin, despite being gram-negative
Clotrimazole: Clotrimazole is a potent, specific inhibitor of p450 enzymes.
It is used in some antifungal medications, and in the treatment of yeast infections.
A. Sympathetic Nervous System Depressants
1. Antagonists
Both α-adrenoceptor antagonists and β-adrenoceptor antagonists are useful antihypertensives.
- α-blocker Prazosin, phentolamine, phenoxybenzamine
- β-blocker Propranolol ,Metoprolol, atenolol
- α/β-blocker labetalol
2. Sympathetic depressants
a. Examples of peripherally acting agents include
- reserpine This agent interferes with the storage of norepinephrine
- quanethidine This agent interferes with the release of norepinephrine
- trimethaphan This agent blocks transmission through autonomic ganglia.
b. Examples of Centrally acting agents include
- alphamethyldopa
- clonidine. These agents act by decreasing the number of impresses along sympathetic nerves.
Adverse Effect
include nasal congestion, postural hypotension, diarrhea, sexual dysfunction, dry mouth. sedation and drowsiness.
B. Directly Acting Vasodilators
Act on vascular smooth muscle cells independently of adrenergic nerves and adrenergic receptors.
Relaxation of vascular smooth muscle which leads to a decrease in peripheral vascular resistance.
Sites of action of vasodilators are many. For example
Calcium Channel Blocker’s MOA
. Decrease automaticity & conduction thru SA & AV nodes
. Decreased myocardial contractility
. Decreased peripheral & coronary
smooth muscle tone = decrease SVR
Potassium channels activators
minoxidil, cause vasodilation by activating potassium channels in vascular smooth muscle.
An increase in potassium conductance results in hyperpolarization of the cell membrane which is associated with relaxation of smooth muscle.
Nitrovasodilators, such as sodium nitroprusside,
Increase in intracellular cGMP. cGMP in turn activates a protein kinase. Directly-Acting Vasodilators are on occasion used alone but more frequently are used in combination with antihypertensive agents from other classes (esp. a β-blocker and a diuretic.)