Green’s Dictionary of Slang

1. (drugs) a period when drugs are hard to purchase; thus panic man n., a dealer or a drug addict who is desperate for supplies.

1916		New Republic VI 22 Apr. 314–6: For a time illicit traffic in the drug almost ceased. This was particularly acute just before the law went into effect on March 1, 1915, a period which is referred to by the ‘cokies’ as ‘the panic’.
1936		D. Maurer ‘Argot of the Und. Narcotic Addict’ Pt 1 in AS XI:2 93/2: panic man. An addict who is desperate for narcotics.
1938		D. Maurer ‘Argot of the Und. Narcotic Addict’ Pt 2 in AS XIII:3 188/2: panic. A scarcity of drugs in a certain city or locality as a result of a raid at the source of supply.
1949		Monteleone Criminal Sl. (rev. edn).
1952		(con. 1948) G. Mandel Flee the Angry Strangers 61: The panic is off. Everybody’s stickin.
1966		J. Mills Panic in Needle Park (1971) 4: Occasionally—perhaps once a year—the stream of illegal drugs is partially dammed, usually at its European source, and then heroin grows scarce. At such times, addicts talk of ‘panic’.
1978		H. Selby Jr Requiem for a Dream (1987) 196: The panics over and therell be stuff on the streets again.
1981		D.E. Miller Bk of Jargon 343: panic: A general heroin shortage; may be due to a series of large busts in the area, or a lack of supply from the source country outside the U.S.
1990		(con. 1930s–60s) H. Huncke Guilty of Everything (1998) 275: The phone rang and my man told me, ‘Huncke, I can’t cop anywhere. There’s a panic on.’.
2001		ONDCP Street Terms 16: Panic — Drugs not available.

2. in fig. uses.