Leprosy Flashcards
multi drug Tx; MOA; Sx of dapsone syndrome; elim/ dose mod in dysfxn; neurologic/teratogenic/immuno suppressive actions
What drugs are given to patients that cannot tolerate clofazimine?
clarithromycin; minocycline; ofloxacin
What is the standard Tx for tuberculoid leprosy?
dapsone and rifampicin for 12 months then D/C therapy
Standard Tx for lepromatous leprosy?
Dapsone, rifampicin, clofazimine for 24 months then D/C therapy
What is an inactive metabolite of dapsone metabolism?
hydroxylamine (potent oxidant)
What will the production of hydroxylamine cause?
methemoglobinemia and hemolysis
Dapsone interaction with rifampin will lead to what?
increased toxicity
dapsone interaction with cimetidine and omeprazole will cause what?
decrease in toxicity
dapsone and trimethoprim lead to what?
increased in serum levels of both drugs
How is dapsone eliminated?
renal (renal fxn important)
What does the interaction of probenecid and dapsone have with elimination?
decreases clearance with renal tubular secretion
What are the MOAs of dapsone?
1) folate antagonsist producing bacteriostatic effect; 2) inhibitor of 2nd msg path involved in neutrophil chemotaxis
What can dapsone syndrome lead to?
hemolysis; methemoglobinemia; hepatitis; cholestatic jaundice; peripheral neuropathy; severe hypoalbuminemia; psychosis; leukopenia; agranulocytosis
How does dapsone syndrome clinically present?
maculopapular or exfoliative rash confined to either upper limbs or forehead
What are the sequence of Sx associated with dapsone syndrome?
dermatitis; LAD along post. border of SCM; hepatitis
What are the clinical indications for dapsone?
acne vulgaris; dermatitis herpetiformis; leprosy
What is the MOA of rifampin?
inhibits bacterial and mycobacterial RNA synthesis via DNA dep RNA polymerase
What type of cells are susceptible to rifampin?
rapidly and slowly dividing organisms
What is the distribution of rifampin?
widely and crosses inflamed meninges; placenta; breast milk
metabolism of rifampin
hepatic (recirculates in entero-hepatic)
elimination of rifampin
hepatic
Rifampin Effects on CYP
INDUCER of CYP with multiple DDI
CYP3A induction by rifampin is variable and affected how?
tissue/intracellular concentration of agonists (P-gp efflux); genetic variations of P450
What is a sometimes fatal ADE associated with rifampin?
transient increases in hepatic enzymes and severe hepatotoxicity
What patients should be monitored while taking rifampin?
diabetics
What are side affects that can scare the patient taking rifampin?
discolor of bodily fluids
Therapy intervals are not less than 2x weekly and may present how?
hemolysis; hemoglobinuria; hematuria; renal tox
MOA for clofazimine
preferential binding to mycobacterial guanine in DNA (non-intercalator)
How does clofazimine improve leprosy?
progressive, dose dep anti-inflam & immunosuppressive
What can clofazimine treat?
reversal rxns and erythema nodosum leprosum
What is significant about the duration and make up of clofazimine?
highly lipophilic so months of persistence => fat and RES system
clofazimine elimination
hepatic => jaundice and hepatitis
What are alarming ADEs associated with clofazimine?
staining of body; body fluids; suckling infant => depression can result
How may clofazimine look like a GI disturbance?
black or tarry feces
What must always be monitored in patients taking clofazimine?
CBC and platelets
What is the MOA of clarithromycin?
inhibits 50S ribosomal sub unit
clarithromycin static or cidal
cidal
clarithromycin and pregnancy
C
MOA of minocycline
inhibits 30S ribosomal subunit
minocylcine static or cidal
cidal
ofloxacin MOA
inhibits bacterial DNA gyrase
ofloxacin static or cidal
cidal
pregnancy and minocycline
D
pregnancy and ofloxacin
C
Resistance to oxfloxacin, minocycline or clarithromycin
rare
ADEs are associated with oxfloxacin, minocycline and clarithromycin. What are considered type 1 rxns? tx for type 1?
red patchy skin lesions; erythema; swollen hands/feet; joint pain
Tx: corticosteroids
What are considered type 2 rxns? Tx for type 2
erythema nodosum leprosum with sudden eruption of painful nodules and neuritis
Tx: corticosteroids; clofazimine; thalidomide
MOA of thalidomide
inhibits NFkB mediated transcriptional upregulation and TNF-a production => block leukocyte migration
What are serious ADEs associated with thalidomide?
teratogen; somnolence > rash > headache; rare peripheral neuropathy
Thalidomide and HIV patients
increase in plasma HIV viral load so must be monitored