Apart from gulping down a few quaffs of cooking sherry when facing mortal danger, our super seven and quite fond of popping the odd pill, sprays and injections every now and again.
Although it's difficult to distinguish which pills are nutritional, when are medicinal and which are recreational, drugs remain a fairly dominant and reoccuring theme in Blakes7.

Adrenaline and Soma makes it's first appearance in Horizon when it's administered intraveniously to Vila by Cally for stress and fatigue shock.
We learn later that Soma is a relaxant, alcohol variant therefore it's primary fuction would be to relax the muscles, raise seratonin level and lower blood-pressure in the short-term. It's probably mixed with synthetic adrenaline (a stimulant) to counteract too many of the Soma sedative side effects - although Vila does pass out 5 or so seconds after he's injected with the concoction - not before declairing 'What ever that was - I'm going to bottle it'.

Freely available on Space City, once addicted to the yellow opaic spherical drug, the user has to keep taking Shadow at regular intervals just to stay alive. Space City residents Hannah and Petie are the only addicts we see, Petie mysteriously dying even when he 'didn't need another shot for hours, he just...died' indicating the dangerous unpredictibily of the drug.

The title of episode 2 series 2, The crew knew much of Shadow before they arrived on Space City. Before her capture by the Federation, Jenna was asked to run a cargo of Shadow into Earth, a crime against the Federation, Avon tells us, which carried 'a madatory death sentence'.

The crew trace Shadow's origins to the planet Zonder and discover that Shadow this made from processing a type of 'Alpha 7oblique5' cactus known as the MoonDisc. A remarkable plant with an ability to whisper, communicate telepathically and move short distances to avoid sunlight. It's love of the shade is where the name 'Shadow' comes from.

Shadow, Adrenaline and Soma and Narcotic Spray are the only drugs in B7 that are given specific names, although many unidentifiable pills are swallows on various occasions for various reasons.
Shadow has many parallels with heroin as it's highly addictive, can be fatal, users appear pale, thin and doped and obtain their drug though profits from crimes. Adrienaline and soma - part adrenaline, part sedative, part intoxicant makes it the 'champagne and cocaine' of space

One of the most baffling episodes regarding drugs is 'Orac'. Slowly dying of radiation sickness while Blake searches for some Decontaminates to cure them, Gan takes a large pill from a large container in the medical bay, despite what ever he took, it didn't seem to help in any way, neither did anything Cally could do despite being in charge of the Liberator's medicinal supplies.
Hours later, their heath having badly deteriorated, Avon and Vila prepare to teleport down to rescue Blake from Aristo. While in the teleport, Avon produces a small bottle of tiny pills, gives one to Vila and orders him to take it. When asked what the pill contained, Avon won't say, simply replying "these will help - for a while, anyway". If it was a pill to ease their condition, wouldn't it be a) kept in the medical bay b) administered by Cally who takes care of all things drug related c) if I was to ease their condition, wouldn't they have taken it hours before they became very ill? And why did Jenna look so angrily at Avon after he and Vila took the pills?
Further proof that Avon's arrogance is down to his secret stash of cocaine pills or just a fan-fictioner's fantasy, who knows. But one this for sure the unexplained pills in 'Orac' are certaining and interesting, if not intreging drug.