NEET MDS Lessons
Pharmacology
Antihypertensives Drugs
CATEGORIES
I. Diuretics to reduce blood volume
Chlorothiazide (Diuril)
II. Drugs that interfere with the Renin-Angiotensin System
A. Converting enzyme inhibitors Captopril , enalapril, Lisinopril
B. Angiotensin receptor antagonists Saralasin Losartan
III. Decrease peripheral vascular resistance and/or cardiac output
A. Directly acting vasodilators
1. calcium channel blockers Nifedipine , Diltiazem, amlodipine
2. potassium channel activators Minoxidil
3. elevation of cGMP Nitroprusside
4. others Hydralazin e
B. Sympathetic nervous system depressants
1. α-blockers Prazosin, phentolamine, phenoxybenzamine
2. β-blockers Propranolol ,Metoprolol, atenolol
3. norepinephrine synthesis inhibitors Metyrosine
4. norepinephrine storage inhibitors Reserpine
5. transmitter release inhibitors Guanethidine
6. centrally acting: decrease
sympathetic outflow Clonidine , methyldopa
Clarithromycin Used to treat pharyngitis, tonsillitis, acute maxillary
sinusitis, acute bacterial exacerbation of chronic bronchitis, pneumonia (especially atypical pneumonias associated with Chlamydia pneumoniae or TWAR), skin and skin structure infections, and, in HIV and AIDS patients to prevent, and to treat, disseminated Mycobacterium avium complex or MAC.
Unlike erythromycin, clarithromycin is acid-stable and can therefore be taken orally without being protected from gastric acids. It is readily absorbed, and diffused into most tissues and phagocytes.
Clarithromycin has a fairly rapid first-pass hepatic metabolism, i.e it is metabolised by the liver. However, this metabolite, 14-hydroxy clarithromycin is almost twice as active as clarithromycin.
Contraindications Clarithromycin should be used with caution if the patient has liver or kidney disease, certain heart problems (e.g., QTc prolongation or bradycardia), or a mineral imbalance (e.g., low potassium or magnesium levels).
Dextromethorphan
O-methylated dextrorphan, Excellent oral antitussive, No analgesic effect, No GI effects, No respiratory depression
Phenobarbital (Luminal): for generalized tonic-clonic and partial seizures (not used for absence seizures)
Mechanism: enhances GABA inhibition (↑ open time of Cl channels in presence of GABA)
Side effects: sedation, ataxia, cognitive impairment, induction of hepatic microsomal enzymes
Phenytoin (Dilantin): for tonic-clonic and all partial seizures (not effective against absence seizures)
Mechanism: ↓ reactivation of Na channels (↑ refractory period, blocks high frequency cell firing, ↓ spread of seizure activity from focus)
Side effects: ataxia, vertigo, hirsutism (abnormal hair growth), gingival hyperplasia, osteomalacia (altered vitamin D metabolism and ↓ Ca absorption), blood dyscrasias (rare; megaloblastic anemia, etc)
Drug interactions: induces hepatic microsomal enzymes (can ↓ effectiveness of other drugs); binds tightly to plasma proteins and can displace other drugs
Propofol -Intravenous Anesthetics
- A nonbarbiturate anesthetic
- It is very lipid-soluble, acts rapidly and has a short recovery time.
- It is associated with less nausea and vomiting than some of the other IV anesthetics.
- Propofol is very similar to thiopental in its effects on the cardiorespiratory system.
- It does not have any analgesic properties but lowers the dose of opioid needed when the two agents are used in combination.
- The most significant adverse cardiovascular effect associated with propofol administration is hypotension. It should be used with caution in patients with cardiac disease.
Antianginal Drugs
Organic Nitrates :
Short acting: Glyceryl trinitrate (Nitroglycerine, GTN), Amyl Nitrate
Long Acting: Isosrbide dinitrate (Short acting by sublingual route), Erythrityl tetranitrate, penta erythrityl tetranitrate
Beta-adrenergic blocking agents : Propanolol, Metoprolol
Calcium channel blockers Verapamil, Nifedipine, Dipyridamole
Mechanism of action
– Decrease myocardial demand
– increase blood supply to the myocardium