Pharmacology for cytopenia Flashcards
Types of iron supplementation
- Oral: ferrous sulfate
- IV: iron sucrose
Elimination of iron
- Minimal in feces, bile, urine, sweat
ADR of iron
Acute:
- Necrotising gastroenteritis with vomiting, abdo pain and bloody diarrhea
- May be followed by shock, lethargy, dyspnea, metabolic acidosis, coma & death
Chronic:
- Hemochromatosis
- Iron deposited in major organs –> failure
Treatment for iron toxicity
- Parenteral deferoxamine
- Oral deferasirox
Types of vit B12 supplementation
Parenteral hydroxocobalamin (preferred to cyanocobalamin)
Elimination of vit B12
- Bile & urine
- Excess stored in the liver
- t1/2: 26-31 hours (IV)
ADR of vit B12
- Photosensitivity
- Injection site pain
- Hypertension, flushing
- Arrhythmias secondary to hypokalemia
- GI disturbance
- Dizziness, headache
- Tremor, parasthesia
- Chromatouria
- Acneiform and bullous eruption
- Rash, itch
DDI of vit B12
PPI (impede absorption)
Absorption of folic acid
- Rapid following PO
- F: 100%
- Peak reached in 1 hour
Metabolism of folic acid
- Liver & plasma
- Converted to active metabolite (5 methytetrahydrofolate)
- Enterohepatic recirculation
Elimination of folic acid
Urine
Contraindications of folic acid
- Untreated cobalamin deficiency (including pernicious anemia)
- Malignant disease
Precautions for folic acid
- Patients with folate-dependent tumor, hemolytic anemia, alcoholism
- Women with pre-existing DM, obesity, FH or previous pregnant history of neural tube defects
- Not to be used as mono therapy for pernicious, aplastic, normocytic anemia (with B12 deficiency)
- Children, pregnancy & lactation
ADR of folic acid
- GI disturbance (bitter taste, nausea, abdo distension, flatulence)
- Immune: allergy, sensitisation
- Anorexia (rare)
DDI for folic acid
- Reduce conc of anticonvulsants
- Increase efficacy of lithium
- Decrease effect of methotrexate
- Elimination increased with aspirin
- Absorption reduced with sulfasalazine & triamterene
- Metabolism disrupted with chloramphenicol, bactrim
Absorption of ESA
IM: slow
SC: slow & incomplete
IV: rapid
Distribution of ESA
Concentrated in liver, kidneys, bone marrow
Metabolism of ESA
Limited protein degradation
Elimination of ESA
- Feces (main), urine (small amounts)
- t1/2: epoetin alpha (4-13 hours), darbepoetin (20-25 hours)
Cautions for ESA
Contraindication
- Uncontrolled hypertension
Caution
- Hypertension
- Ischemic vascular disease
- History of seizures
- Hepatic / renal impairment
- Sickle cell anemia
- Children, pregnancy, lactation
ADR of ESA
- Hypertension, edema
- Increased platelet
- Thrombosis, stroke
- Hyperkalemia
- Seizures
- Myalgia, arthralgia, limb pain
- GI (N,V)
Epoetin alpha: pruritus
Darbepoetin: dyspnea, cough, bronchitis
Examples of myeloid GFs
G-CSF:
- Filgrastim
- Pegfilgrastim
- Plerixafor
GM-CSF
- Sargramostim
ADR of myeloid GFs
- G-CSF better tolerated
G-CSF:
- Bone pain (reversible)
GM-CSF:
- Fever, malaise
- Arthralgia, myalgia
Severe:
- Sickle cell crisis
- Capillary leak syndrome
- ARDS
- Splenic rupture (rare)
Cautions for myeloid GFs
- Pts with pre-malignant or malignant myeloid conditions
- Acute myeloid leukaemia
- Sickle cell diseases
- Recent history of pneumonia or lung infiltrates
- Osteoporotic bone disease
- Not indicated for chronic myeloid leukaemia or myelodysplastic syndrome!!
