Sibutramine is a norepinephrine, 5-HT and dopamine reuptake inhibitor that is used as a weight-loss agent.

LITHIUM, carbamazepine, and valproate are drugs used for the treatment of bipolar disorder.

LITHIUM has a low therapeutic index and the frequency and severity of adverse reactions is directly related to the serum levels.

Diuretics: Site of action & Mechanism

Osmotic Diuretics: =/=> water reabsorption throughout the tubules, but mostly in the proximal tubule (mannitol)

Carbonic Anhydrase Inhibitors: proximal tubule, =/=> C.A (acetazolamide, dorzolamide)

Loop Diuretics: thick ascending loop of Henle, =/=> Na+/K+/2Cl- transporter (furosemide, ethacrynic acid)

Thiazides: early distal tubule, =/=> Na+/Cl- symporter (hydrochlorothiazide, indapamide)

K+ sparing agents: distal nephron (late distal tubule + colecting ducts). Aldosterone receptor antagonist (spironolactone) or =/=> Na+/K+ exchange by =/=> of Na+ channels (amiloride, triamterene)

The penicillins, cephalosporins, vancomycin, imipenem, and aztreonam all work by inhibiting the synthesis of the bacterial cell wall.

Some bacteria inactivate the β-lactam antibiotics by an enzyme that opens the β-lactam ring.

CLAVULANIC ACID and SULBACTAM are β-lactamase inhibitors that are given together with the β-lactam drugs to increase their effectiveness.

Penicillins are excreted by tubular secretion that can be blocked by probenecid.

The most important adverse effect of penicillins as a group is the hypersensitivity reaction. It can be fatal.

All penicillins can give rise to allergic reactions. These reactions have been divided into three types: immediate, accelerated, and late. The immediate is the most severe.

The immediate reaction occurs within 20 minutes after parenteral administration and consists of apprehension, itching (pruritus), paresthesia (numbness and tingling), wheezing, choking, fever, edema, and generalized urticaria (hives). It can lead to hypotension, shock, loss of consciousness, and death. The immediate hypersensitivity reaction to penicillin appears to be mediated by IgE antibodies to the minor determinants.

The accelerated reaction appears 1-72 hours after drug administration and it consists mainly of urticaria (hives).

The late reaction is more common with the semisynthetics and appears 72 hours to several weeks after drug administration. It consists mainly of skin rashes.

CARBAPENEMS:
This class of β-lactam antibiotics contains imipenem, doripenem, ertapenem, and meropenem. All are administered intravenously.

AZTREONAM is an excellent drug for aerobic gram-negative bacteria, including Pseudomonas, but it is ineffective against gram-positive organisms.

VANCOMYCIN is only effective against the gram-positive organisms. It is very poorly absorbed orally.

Bacitracin is a mixture of polypeptides that inhibit cell wall synthesis. It is used topically.

FOSFOMYCIN:
Fosfomycin inhbits one of the first steps in the synthesis of peptidoglycan (ie, the cell wall) by inhibiting the enzyme enolpyruvyl transferase. It is used for the treatment of uncomplicated urinary tract infections.

Aminoglycosides are poorly absorbed from the GI tract.

Aminoglycosides have ototoxicity, nephrotoxicity, and neuromuscular toxicity.

Erythromycin and it relatives are of particular use in the treatment of patients with Mycoplasma infections, pneumonia, Legionnaires disease, chlamydial infections, diphtheria, and pertussis.

The quinolones inhibit DNA synthesis through a specific action on DNA gyrase.

Methenamine is metabolized to formaldehyde and ammonia and is used in urinary tract infections.