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Cardiac toxicity


Cardiac glycosides


The following plants have digitalis like cardiac glycosides or aglycones with some of them having minor cross reactivity with digoxin assays and Fab fragments. (100:1 compared with bioassays of digitalis like effect).

Toxicity is often prolonged (6-7 days). The major clinical manifestations are VEBs, conduction block, hyperkalaemia, nausea, vomiting and yellow haloes.

Treatment is as for digitalis, with repeated doses of charcoal and careful fluid and electrolyte balance. Digoxin Fab fragments are of benefit but large doses are needed due to the limited cross reactivity. They should be considered if there is serious toxicity (see Yellow oleander and digoxin poisoning).

Cardenolides


Bufadienolides

  • Mother of millions (Bryophyllum)
  • Cape tulips (Homeria)
  • Toads (family Bufonidae; genera Bufo, Atelopus, Dendrophryniscus and Melanophryniscus)
    • (OK, we know they're not plants)

Other cardiotoxins

The following plants are cardiac toxins by different and largely unknown mechanisms. The most common manifestations shown are

Arrhythmias
  • Delphinium
  • Colchicum
  • Yew (Taxus spp.)
  • Mistletoe

Pulmonary oedema
  • Rhododendron
  • Lantana

Nicotinic and anticholinergic plants may also cause tachycardia but cardiac toxicity is not the major manifestation.

2.3.4.1.2 Aconitum napellus