Pharmacol Toxicol 1989 Jan 01;641:78-82. doi: 10.1111/j.1600-0773.1989.tb00605.x.

Teratogenic effects of some calcium channel blocking agents in Xenopus embryos.

Abstract
Xenopus embryos, treated for three days from the early cleavage stage with the calcium channel blocking drugs nifedipine, diltiazem, verapamil or nicardipine continue to develop in water. By the seventh day many developmental abnormalities appear, the most reproducible affecting the central nervous system, failure of forebrain development, synophthalmia and neural tube defect. Other anomalies include failure of mandibular growth and malrotation of the gut. Failure of water and electrolyte transport are indicated by severe oedema in some animals. The defects appear to relate to calcium ion antagonism, and provide a pharmacological model for some forms of teratogenesis in which large populations can be studied readily.

PubMed ID: 2755914
Article link: Pharmacol Toxicol