Grab our best-selling pharmacology coloring book!


Uterine Relaxant Drugs

πŸ‘ΆπŸ» Preterm labor occurs when labor begins too early. If this happens before the 37th week of gestation, the fetal organs, especially the lungs, might not be fully developed.⁠
πŸ’Š In these cases, labor can be suppressed with uterine relaxants that relax the uterine muscle and slow down contractions for up to 48 hours. It gives the fetus a few more days in the uterus as a corticosteroid is given to speed up the development of a preterm infant’s lungs. Steroids help the lungs mature and may promote the production of surfactant, a substance that prevents the collapse of alveoli (small sacs in the lungs where the air is exchanged). ⁠
πŸ’Š Uterine relaxants are also called tocolytics (toco = childbirth, lytic = terminate) and include several different types of drugs. ⁠

Calcium Channel Blockers

Calcium channel blockers (CCBs) are used in the treatment of many cardiovascular conditions. They are divided into subclasses, non-dihydropyridines and dihydropyridines.

The non-dihydropyridine CCBs cause less vasodilation and more cardiac depression than dihydropyridine CCBs (hence why they are not recommended in decompensated heart failure). They cause reductions in heart rate and contractility.

Dihydropyridine CCBs have more vascular selectivity and fewer cardiac effects. They are indicated in the treatment of hypertension and angina. They do not suppress AV conduction or the SA node automaticity.