Drug name: Cefuroxime
Generic name: Axetil
Pharmacodynamics:
Cefuroxime is a prodrug of the bactericidal cephalosporin antibiotic Cefuroxime, which
is resistant to most b-lactamases and is active against a wide range of Gram-positive and Gram
negative organisms. It owes its in vivo bactericidal activity to the parent compound Cefuroxime.
It ia well-characterized and effective antibacterial agent. It is consequently active against any
ampicillin-resistant or amoxicillin-resistant strains.
Pharmacokinetics:
Through oral administration, it is absorbed from the GIT and rapidly hydrolyzed by
nonspecific esterases in the intestinal mucosa and blood to cerufoxime. It is subsequently
distributed throughout the ECF.
Indications:
It is used in the treatment of susceptible infections. Those have included bone and joint
infections, bronchitis, gonorrhea, meningitis, otitis media, peritonitis, pharyngitis, sinusitis, skin
infections and UTI. It is also used for surgical infections prophylaxis.
Contraindications:
Patients with known hypersensitivity to cephalosporin antibiotics and to any ingredients
of this product.
Dosage:
The drug should be taken with food for optimum absorption. In adult: bronchitis and
pneumonia 500mg twice daily should be given. Most infections in other sites will respond to 250
mg twice daily. A single dose of 1 gram is recommended for the treatment of uncomplicated
gonorrhea or as prescribed by the physician.
Antiviral
Drug name: Lamivudine
Generic name: Zeffix
Pharmacodynamics:
Lamivudine, an antiviral agent that is highly active against hepaB virus in all cell lines
tested and in experimentally infected animals. It is metabolized by infected and also by unifected
cells to the triphosphate( TP) derivative. The intracellular half life of the TP in hepatocytes is 17
to 19 hours in vitro. Lamivudine-TP acts as a substrate for the HBV viral polymerase. It blocks
the further formation of viral DNA. It does not interfere with normal cellular deoxynucleotide
metabolism. It is also a weak inhibitor of mammalian DNA polymerases alpha and beta.
Lamivudine lacked appreciable toxic effects relating to potential drug effects on
mitochondrial structure and DNA content and function. It has very low potential to decrease in
mitochondrial DNA content, is not permanently incorporated into mitochondrial DNA and does
not act as an inhibitor of mitochondrial polymerase gamma.
Pharmacokinetics:
Lamivudine is well absorbed from the GIT and the bioavailability of oral lamivudine in
adults is normally between 80 and 85%. Following oral administration, the mean time (tmax) to
maximal serum concentrations (Cmax) is about an hour. At therapeutic dose levels i.e. 100mg
once daily, Cmax is in the order of 1.1 to 1.5 micrograms/mL and trough levels mere 0.015 to
0.020 micrograms/mL. Delay of tmax and lower Cmax results when co-administration of
lamivudine with food. However, the extent of lamivudine absorbed was not influenced, which
concludes that it can be administered with or without food.
From i.v/ studies, the mean volume of distribution is 1.3L/kg. Lamivudine exhibits linear
pharmacokinetics over the therapeutic dose range and displays low plasma protein binding to
albumin. Lamivudine penetrates the CNS and reaches the CSF. The mean lamivudine
CSF/Serum concentration ratio 2 to 4 hours oral administration was approximately 0.12.
Lamivudine is predominantly cleared by renal excretion of unchanged drug. It has small
extent of hepatic metabolism and low plasma protein binding so the metabolic drug interaction is
low.
The mean systemic clearance of lamivudine is approximately 0.3L/h/kg. the observed
half life elimination is 5 to 7 hours. The majority of lamivudine is excreted unchanged in the
urine via glomerular filtration and active secretion. Renal clearance accounts for about 70% of
lamivudine elimination.
Indications:
Lamivudine is indicated for the treatment of patoients with chronic hepatitis B and
evidence of hepatitis B virus replication.
Contraindications:
Lamivudine oral solution and tablets are contraindicated in patients with known
hypersensitivity to Lamivudine or to any ingredient of the preparations.
Dosage:
Lamivudine can be administered with or without food intake. Discontinuation of the drug
may be considered when loss of efficacy occurs, and patients should be monitored for evidence
of recurrent hepatitis.
Recommended dosage for adults and adolescents 12 yrs old and older is 100mg once
daily, children from 2 to 11 years old is 3 mg/kg once daily up to a maximum of 100mg daily,
and in renal impairments, lamivudine serum concentrations is increased in patients with
moderate or severe renal impairment due to decreased renal clearance. When doses below 100
mg are required of this drug, oral solution should be used.
