Known as “Typical Anti-psychotics” (sometimes referred to as first conventional antipsychotics, classical neuroleptics, traditional antipsychotics, or major tranquilizers), these were the first medications used to treat psychosis developed in the 1950s. They have subsequently been replaced by Second-Gen Anti-psychotics, but are still used in some settings for some purposes.
For example, in the hospital setting, you will encounter Haldol (haloperidol). It is most often used for agitation and takes effect quickly.
However, there is a higher risk of side effects with the first-gens. Most notably being tardive dyskinesia. Additional side effects include dry mouth, muscle stiffness, muscle cramping, tremors, EPS and weight gain. EPS refers to a cluster of symptoms consisting of akathisia, parkinsonism, and dystonia.
If you are prescribed a first generation anti-psychotic, most settings will also prescribe a medication such as Cogentin (benzatropine). While a Parkinson drug, it has been shown to reduce the side effects of antipsychotics. It may also be prescribed to reduce the side effects from Second-Gen Anti-psychotics.