Wat is het verschil in toepassing tussen de gedroogde en heptahydraatvorm van magnesiumsulfaat?

Bij toepassingen wordt er door Martindale geen verschil gemaakt in de verschillende hydraatvormen van magnesium sulfaat. Zowel het heptahydraat als de anhydrische/droge vorm kunnen inwendig gebruikt worden.
Martindale beschrijft:
“Magnesium salts also act as osmotic laxatives (see Constipation, p.1693); the salts generally used for this purpose are magnesium sulfate (an oral dose of 5 to 10 g in 250 mL of water being given for rapid bowel evacuation) and magnesium hydroxide (p.1743).
Parenteral magnesium sulfate has some specific uses. It is used for the emergency treatment of some arrhythmias such as torsade de pointes (see below) and those associated with hypokalaemia (p.1669). […]
Parenteral magnesium sulfate is also used for the prevention
of recurrent seizures in pregnant women with eclampsia (see below). […]
The use of magnesium sulfate in acute myocardial infarction and premature labour is discussed below.
Dried magnesium sulfate has been used in the form of Magnesium Sulphate Paste (BP 2008) as an application to inflammatory skin conditions such as boils and carbuncles, but prolonged or repeated use may damage the surrounding skin”