Terrene

Terrene is an arcanoeffective drug that acts as both a mild sedative and an arcanorestrictor. It is sometimes used as a medicine to treat those with overactive symptoms of arcane nature, such a haemoarcane psychosis or severe halucinations related to untempered magic. It is also used in arcane correctional facilities to contain dangerous magically-gifted prisoners, as well as part of programs to contain magic considered dangerous, such as that possessed by chaos sorcerers. Occasionally, it can be used as a weapon during times of war.
The drug can be taken through a variety of routes, but favoured administration is usually via oral tablet form, or as a nasal spray. Common physical side effects include sleepiness and grogginess, nausea and vomiting, respiratory depression, and psychological effects. It is not considered addictive or dependence-forming. Though it can cause some respiratory depression, it seems this effect does not slow breathing enough to be dangerous, even in incredibly high doses. The combination of these features mean the drug is generally considered to be very safe. 
Terrene functions by physically repelling magic. When enough is ingested, its presence in the cells and bloodstream are enough to disrupt magical processes enough to stop it from working. It is thought the sedation and side effects it causes are a result of also disrupting some normal nerve pathways. 

Medical Uses

Medically, terrene is used to treat severe problems that stem from use of magic, particularly in the case of conditions caused by an overactive arcane system. Haemoarcane psychosis, a common side effect of practising blood magic, is often considered treatable with terrene when still in early stages. Halucinations, brain-zaps and mental disturbance caused by an overactive chaos magic system can be very effectively treated with terrene as well, and it is commonly used as pro re nata treatment in countries where chaos magic is not restricted or criminalised. It has even shown some promise in restricting and restraining those affected by more rare supernatural arcane problems, such as possession or curses, allowing experienced practitioners time and safety to explore the problem and treat more thoroughly.

Other Uses

In countries where there are limitations and laws placed on those born with chaos magic, it is often a condition of their release to the general population that they take terrene regularly to ensure they are not a danger to the public. It is routinely given to prisoners in arcane holding facilities and prisons, either in oral form or through flooding blocks of cells with atomised terrene in a gas form.
Terrene is not a particularly enjoyable drug, and is very rarely used recreationally. Because of this, there are no laws on who can produce and sell terrene, and the only real restriction to anyone getting their hands on it is finding a skilled-enough chemist, and price. One such non-medical major use of terrene is the supression of chaos magic in chaosmarked children, in an attempt to "break" their magic before it becomes potent. Using the drug this way is not well studied. Though it seems this may stunt an individual's ability to cast magic long-term and affect their chaos magic outbursts, it is more commonly thought this is simply because the children have not had the chance to experiment and practice rather than an actual suppression of the magic in their blood.

Psychological Concerns

A significant and often overlooked (or ignored) side effect of using terrene is the severe dissociation and depression that can come with having a connection with magic severed. Many who have been forcibly given the drug through correctional services report feeling as though a second half of their self has been taken from them. This can cause a feeling of grief, loss and emptiness and is considered by many to be incredibly cruel. 

Production

Terrene is a chemical extracted from fungus from the mundanus genus- also known as "sorcerer's bane" or "warrior's cup". These small mushrooms that grow in magically-dense caves and Underdark have long been known to harbour magic-suppressant functions. They fill a niche to be able to grow in places so dense with harmful magical energy that other fungus or plants would wither, and have evolved a chemical structure that simply bounces magic away. 
The fungus has to be broken down and skillfully processed to be ingestable, as the mushrooms also happen to be toxic. The terrene can be extracted from the fungus singularly, and then broken down to a molecular size and structure that can be dissolved and pass into the bloodstream and be taken up by cells.
Terrene can be incredibly expensive to produce, as the fungus it is made from is hard to source. A few talented mycologists have been able to re-grow mundanus in labs, but most species seem very particular about air quality and light levels. Most producers of terrene source wild-picked fungus for their product, and concerns about the scarcity of mundanus are growing with each passing year.

Item type

Drug / Narcotic / Medicine

Base Price

1.5 gp per gram