mercury compounds/mercurials and preservatives and anti tb agents Flashcards
MOA: reacts with SULFHYDRYL (-
SH) groups in enzymes and other
proteins
* this is reversible by thiol-containing
compounds such as CYSTEINE and
DIMERCAPROL
MERCURY COMPOUNDS
MERCURIALS
uses of mercurials
antiseptic, disinfectant, and preservatives
- Corrosive sublimate
- HgCl2
mercuric chloride
- Calomel
- Hg2Cl2
mercurous chloride
- HgNH2Cl
- White precipitate
- used for skin infections
ammoniated mercury
- was once a very popular
antiseptic for skin and ocular
infections
nitromersol
- Merthiolate® - old
- weak bacteriostatic antiseptic that is
applied topically in ointments or
aqueous solutions
thimerosal
- used to prevent microbial contamination
- Ideal Characteristics: effective at low
concentrations against all possible
microorganisms, nontoxic, compatible
with other constituents used in the
preparation, stable for the shelf-life of the
preparation
preservatives
p-hydroxybenzoic acid
* useful as preservative for liquid dosage
forms
* have ANTIFUNGAL properties
* preservative effect tends to increase with
molecular weight
Parabens
- more effective against molds
methylparabens
- more effective against yeasts
- more oil-soluble so it is preferred for
oils and fats
PROPYLPARABEN
employed as a bacteriostatic agent in
pharmaceuticals for injection, ophthalmic
use, and intranasal administration
CHLOROBUTANOL
commonly used as preservative in vials of
injectable drugs in concentrations of 1%
to 4% in water or saline solution; has
local anesthetic action
BENZYL ALCOHOL (Phenylcarbinol,
Phenylmethanol)
occurs naturally in rose oil and pine-needle
oil; used primarily in perfumery
PHENYLETHYL ALCOHOL
used externally as an antiseptic for lotions,
ointments and mouthwashes; more
effective as a preservative in foods and
pharmaceutical products at low pH
BENZOIC ACID
used as preservative in acidic liquid
preparations in which benzoic acid is
releases
SODIUM BENZOATE
effective antifungal that is used as preservative
SODIUM PROPIONATE
an effective antifungal preservative; used to
preserve syrups, elixirs, ointments, and lotions
containing components such as sugars that
support mold growth
SORBIC ACID
used as the same way as sorbic acid
POTASSIUM SORBATE
used to preserve injectable drugs but bacteriostatic
efficacy is reduced in the presence of serum
PHENYLMERCURIC NITRATE
used as preservative
PHENYLMERCURIC ACETATE
- Acid fast bacteria
- Rod shaped, aerobic bacteria that
does not form spores - facultative intracellular, obligate
aerobe - causes Koch’s disease
- Lowenstein-Jensen medium
(serpentine growth colonies)
Mycobacterium tuberculosis
- Isonicotinic acid hydrazide
- Nydrazid®
- MOA: inhibits the synthesis of mycolic
acid, an important component of the cell
wall of mycobacteria - Principal adverse effect: Peripheral
neuritis due to the competition of INH with
pyridoxal phosphate for the enzyme
apotryptophanase - co-administration of pyridoxine prevents
peripheral neuritis
ISONIAZID (INH or H)
- Trecator SC®
- structural analogue of isoniazid
- used in the treatment of isoniazidresistant tuberculosis
- S/E: GI irritation, hepatotoxicity,
peripheral neuropathies, optic
neuritis
Ethionamide
- Pyrazinecarboxamide
- MOA: unknown
- used in combination with other
agents because resistance develops
rapidly - S/E: hepatotoxicity (inc. ALT/AST)
- must be enzymatically hydrolyzed to
pyrazinoic acid (active form)
Pyrazinamide (PZA or
Z)
- Myambutol®
- S/E: Optic neuritis
- loss of ability to discriminate
between red and green - MOA: inhibits the incorporation of
mycolic acids in the cell walls of the
bacteria
Ethambutol (EMB or E)
- MOA: acts as a competitive
inhibitor for p-aminobenzoic acid
(PABA) in folate biosynthesis - S/E: severe gastric irritation
- second-line treatment for TB
Para-Aminosalicylic Acid (PASA/PAS)
- Lamprene®
- MOA: unkwown
- basic red-dye used in the
treatment of leprosy, includdapsone-resistant forms - S/E: Colored-maroon urine
Clofazimine
