Thuốc kháng lao

Pharmacology

Absorption: oral: well absorbed; food may delay or slightly reduce peak
Distribution: highly lipophilic; crosses blood-brain barrier well, relative diffusion from blood into CSF: adequate with or without inflammation (exceeds usual MICs), CSF: blood level ratio: inflamed meninges: 25%
Protein Bound: 80%
Half-life elimination: 3-4 hr; prolonged with hepatic impairment; end-stage renal disease: 1.8-11 hr
Peak Plasma Time: Oral: 2-4 hr
Metabolism: hepatic; undergoes enterohepatic recirculation
Excretion: feces (60-65%) and urine (~30%) as unchanged drug

Mechanism of Action

Inhibits DNA-dependent RNA polymerase; potent enzyme inducer (see Enzyme Induction and Inhibition: General Principles)

 

Adult Dosing & Uses

Dosing Forms

capsule

• 150mg
• 300mg

injectable powder

• 600mg

Tuberculosis (TB)

Daily dose: 10 mg/kg PO qD
2x/week: 10 mg/kg PO 2x/week
No more than 600mg/d

Other Information

No more than 600 mg/d
Take on empty stomach

Adverse Effects

1-10%

Increased LFTs (up to 14%)
Rash (1-5%)
Epigastric distress (1-2%)
Anorexia
Nausea
Vomiting
Diarrhea
Cramps
Pseudomembranous colitis
Pancreatitis

Frequency Not Defined

Muscular weakness

Contraindications & Cautions

Contraindications

Hypersensitivity to rifamycins
Concomitant live bacterial vaccines
Contraindicated in patients receiving ritonavir-boosted saquinavir due to an increased risk of severe hepatocellular toxicity
Contraindicated in patients receiving atazanavir, darunavir, fosamprenavir, saquinavir, or tipranavir due to the potential of rifampin to substantially decrease plasma concentrations of these antiviral drugs, which may result in loss of antiviral efficacy and/or development of viral resistance

Cautions

May decrease the effectiveness of OCPs
Do not administer parenteral IM or SC
History of diabetes mellitus (may make diabetes management more difficult)
Rifampin is not recommended for intermittent therapy; caution patient against intentional or accidental interruption of daily dosage regimen since rare renal hypersensitivity reactions have been reported when therapy was resumed in such cases
Rifampin has enzyme induction properties that can enhance the metabolism of endogenous substrates including adrenal hormones, thyroid hormones, and vitamin D

Pregnancy & Lactation

Pregnancy Category: C
Lactation: enters breast milk

Nguồn : Medscape