6 Questions
What is the primary mechanism of action of this medication?
Inhibition of purine and pyrimidine synthesis
What is a common indication for this medication?
Treatment of leukemia
What is the primary route of excretion for this medication?
Urine
What is a common adverse effect of this medication?
Nausea and vomiting
What is a contraindication for this medication?
Pregnancy
What laboratory test should be monitored regularly in patients taking this medication?
Complete Blood Count (CBC)
Study Notes
Mechanism of Action
- Inhibits dihydrofolate reductase, an enzyme involved in the synthesis of purines and pyrimidines
- Decreases the production of nucleotides, thereby inhibiting cell division and growth
Indications
- Cancer treatment (e.g., leukemia, lymphoma, breast cancer)
- Autoimmune diseases (e.g., rheumatoid arthritis, psoriasis)
- Ectopic pregnancy
- Abortion (in combination with misoprostol)
Pharmacokinetics
- Oral bioavailability: 33-75%
- Peak plasma concentration: 1-2 hours
- Half-life: 3-10 hours
- Excreted mainly in the urine
Adverse Effects
- Gastrointestinal: nausea, vomiting, diarrhea, stomatitis
- Hematological: bone marrow suppression, anemia, thrombocytopenia
- Hepatic: elevated liver enzymes
- Dermatological: skin rash, alopecia
- Pulmonary: pneumonitis
Contraindications
- Pregnancy (category X)
- Breastfeeding
- Severe renal impairment
- Severe hepatic impairment
- Active infection
Monitoring
- Complete Blood Count (CBC) regularly
- Liver function tests (LFTs) regularly
- Renal function tests regularly
- Monitor for signs of infection and bleeding
Mechanism of Action
- Inhibits dihydrofolate reductase, an enzyme involved in purine and pyrimidine synthesis
- Decreases nucleotide production, inhibiting cell division and growth
Indications
- Cancer treatment (e.g., leukemia, lymphoma, breast cancer)
- Autoimmune diseases (e.g., rheumatoid arthritis, psoriasis)
- Ectopic pregnancy
- Abortion (in combination with misoprostol)
Pharmacokinetics
- Oral bioavailability: 33-75%
- Peak plasma concentration: 1-2 hours
- Half-life: 3-10 hours
- Mainly excreted in the urine
Adverse Effects
- Gastrointestinal: nausea, vomiting, diarrhea, stomatitis
- Hematological: bone marrow suppression, anemia, thrombocytopenia
- Hepatic: elevated liver enzymes
- Dermatological: skin rash, alopecia
- Pulmonary: pneumonitis
Contraindications
- Pregnancy (category X)
- Breastfeeding
- Severe renal impairment
- Severe hepatic impairment
- Active infection
Monitoring
- Regular Complete Blood Count (CBC)
- Regular liver function tests (LFTs)
- Regular renal function tests
- Monitoring for signs of infection and bleeding
Learn about the mechanism of action of methotrexate, its indications, and pharmacokinetics. This quiz covers its use in cancer treatment, autoimmune diseases, and more.
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