Glyceryl trinitrate

Indications

Administration/Absorption

    • The effectiveness of glyceryl trinitrate is limited by development of tolerance/tachyphylaxis within 2-3 weeks of sustained use

    • Continuous administration and absorption accelerate onset of tolerance and limit the usefulness of the agent

    • Thus glyceryl trinitrate works best when used only short term, pulse dosing

      • tablet placed under the tongue or a spray into the mouth

Dosage

Distribution

Mechanism

    • Vasodilator

    • prodrug which must first be denitrated to produce the active metabolite NO

    • NO is a potent activator of guanylyl cyclase (GC) by heme-dependent mechanisms

      • results in cGMP formation from guanosine triphosphate (GTP)

      • cGMP then activates myosin light chain phosphatase via a cGMP-dependent protein kinase.

Excretion

Side effects

  • bradycardia

    • syncope

    • heartburn

    • flushing

    • site reactions in mouth

Interactions

Contraindications

    • Anaemia

    • Cerebrovascular disease

    • Toxic pulmonary oedema