The latest in a seemingly endless series of plays about crumbling marriages, Michael Weller’s Side Effects never manages to transcend its formulaic aspects. This companion piece to the playwright’s Fifty Words-- presented a few seasons back at the same theater--is yet another portrait of two people who are clearly in love but have reached a crossroads in their relationship.

Theatergoers need not have seen the earlier work to be immersed in the world of Hugh (Cotter Smith) and Melinda (Joely Richardson), a seemingly picture-perfect couple. He is a handsome, successful businessman being groomed for big things in Midwestern politics. She’s an acclaimed writer whose lithe gorgeousness is only accentuated by her perfect sense of style.

But not surprisingly, there are cracks beneath the glossy surface. The emotionally closed Hugh, the heir to a successful manufacturing company, has seen his business begin to fail. Melinda suffers from bipolar disorder, a condition that is worsened by her refusal to hew to her pharmaceutical regime.

During the course of several encounters depicted over ninety minutes, we watch as the pair’s relationship unravels in the face of dual infidelities, political machinations, and a potential scandal involving the couple’s teenage sons.       

Although the playwright’s gifts for incisive characterizations and sharply tinged dialogue, previously exhibited in such works as Loose Ends and Spoils of War, remains undiminished, his pile-on of melodramatic incidents here has a contrived, artificial feel. When Melinda makes a furtive phone call to her lover (a character from Fifty Words) merely seconds after Hugh has left the room, it smacks more of plot machination than reality, even if the character’s recklessness has been well established.

Director David Auburn, a celebrated playwright in his own right (Proof), is unable to bring much credibility to the proceedings. What makes the evening work to the extent that it does are the finely calibrated performances by the two actors. Smith, an expert at playing tightly wound, Type-A alpha males, well conveys Hugh’s underlying vulnerability, while Richardson, delivering her character’s sharp retorts with enjoyable gusto, perfectly captures both Melinda’s emotional volatility and her irresistible allure.

 Also adding to the overall effect is Beowulf Boritt’s set, which starts out as a tasteful representation of a beautifully appointed suburban home that, like the relationship between the characters inhabiting it, is ultimately reduced to an empty shell.

Lucille Lortel Theatre, 121 Christopher St. 212-279-4200. www.ticketcentral.com.