(8β)-N-heteroalkyl-1- alkyl-6-(substituted) ergoline-8-carboxamides of the formula
 wherein:
R¹ is C₁-C₄ alkyl;
R² is allyl or C₁-C₄ straight chain alkyl;
R³ is hydrogen or C₁-C₄ straight chain alkyl;
R⁴ is pyridinyl or imidazolyl;
alk is a divalent organic radical derived from a straight or branched C₁-C₅ alkane; or
a pharmaceutically acceptable acid addition salt thereof.
The compounds are useful for blocking 5HT₂ receptors in mammals having an excess of serotonin centrally or peripherally  
                            (8β)-N-杂烷基-1-烷基-6-(取代的)麦角啉-8-甲酰胺,其式为
 其中
R¹ 是 C₁-C₄ 烷基;
R² 是烯丙基或 C₁-C₄ 直链烷基;
R³ 是氢或 C₁-C₄ 直链烷基;
R⁴ 是
吡啶基或
咪唑基;
烷基是二价有机基,来源于直链或支链 C₁-C₅ 
烷烃;或
其药学上可接受的酸加成盐。
这些化合物可用于阻断中枢或外周羟
色胺过量的哺乳动物的 5HT₂ 受体。