Forms
Salts
Cocaine – a tropane alkaloid – is a weakly alkaline compound, and can therefore combine with acidic compounds to form salts. The hydrochloride (HCl) salt of cocaine is by far the most commonly encountered, although the sulfate (SO42-) and the nitrate (NO3−) salts are occasionally seen. Different salts dissolve to a greater or lesser extent in various solvents – the hydrochloride salt is polar in character and is quite soluble in water. Base
As the name implies, "freebase" is the base form of cocaine, as opposed to the salt form. It is practically insoluble in water whereas hydrochloride salt is water-soluble. Smoking freebase cocaine has the additional effect of releasing methylecgonidine into the users system due to the pyrolysis of the substance (a side effect which insufflating or injecting powder cocaine does not create). Some research suggests that smoking freebase cocaine can be even more cardiotoxic than other routes of administration because of methylecgonidines effects on lung tissue and liver tissue.Pure cocaine is prepared by neutralizing its compounding salt with an alkaline solution, which will precipitate non-polar basic cocaine. It is further refined through aqueous-solvent liquid–liquid extraction. Crack cocaine
Crack is usually smoked in a glass pipe, and once inhaled, it passes from the lungs directly to the central nervous system, producing an almost immediate "high" that can be very powerful – this initial crescendo of stimulation is known as a "rush". This is followed by an equally intense low, leaving the user craving more drug.
Trigeminal autonomic cephalalgia (TAC) is the name for a type of primary headache that occurs with pain on one side of the head in the trigeminal nerve area and symptoms in autonomic systems on the same side, such as eye watering and redness or drooping eyelids. TACs include

Cluster headache
Paroxysmal hemicrania (chronic or episodic)
Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT)
Short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA)
Long-lasting autonomic symptoms with hemicrania (LASH)TACs can be differentiated by the length and frequency of recurrence of the headaches.Treatment for TACs varies depending on the exact type, but can include medication such as Indomethacin (in the case of chronic paroxysmal hemicrania) or acute and prophylactic therapy (in the case of cluster headache). == References ==