The plays of Pam Gems have often focused upon celebrated figures – from Queen Christina to Edith Piaf, Stanley Spencer to Marlene Dietrich – with the playwright attempting to examine the human reality behind iconic images. But the work that helped to make Gems' name was actually a more intimate affair centred entirely on the experiences of "ordinary" characters in a relatable domestic situation.

Dusa, Fish, Stas and Vi, which premiered at Edinburgh Festival Fringe in 1976 under the less-alluring title Dead Fish and which then had great success in its transfer to London, takes as its focus the lives of four young women sharing a tiny flat. Often described as a landmark of 1970s feminist theatre, Gems' play looks a little thinner in its weave and more contrived in its design than it might have done in 1976; it's not, after all, as deeply textured or richly complex a piece of work as its reputation might suggest.

Still, Helen Eastman's piquant, well-acted and surprisingly tuneful revival at the Finborough (staged to commemorate the centenary year of the death of suffragette Emily Wilding Davison) nonetheless proves a welcome event, and a worthy addition to the Finborough's reliable repertoire of revivals.

The play concerns the arrival of Dusa, an anxious twenty-something who's just separated from her husband, at the bedsit owned by her friend Fish and shared by Fish's flatmate Stas. Though Dusa discovers that the flat already has another lodger - the teenager Vi - room is made for her, and as the four women set about adjusting to each other, the details of their individual lives and personalities start to emerge and entwine. Dusa is fretting about the fate of her two children following the split. Stas is a physiotherapist moonlighting as a prostitute in order to fund her prospective PhD in marine biology. Vi is an anorexic who's aborted an unwanted baby. And Fish, a campaigner inspired by the left-wing German revolutionary Rosa Luxemburg, is embroiled in a tricky relationship with her partner, Alan.

The impact of Dusa, Fish, Stas and Vi isn't hard to see. The play's short, blurty scenes, its crude sex talk, its spliff-sharing, its occasional surges into melodrama and its attempt to dramatise unspoken aspects of women's lives has influenced everything from TV's much-missed Pulling to Amelia Bullmore's correspondingly titled - and similarly-themed – recent Hampstead hit Di and Viv and Rose.

Clearly, Gems has constructed her quartet as representatives of contradictory/complementary aspects of femininity, and uses them to demonstrate her thesis that all of the four women, though apparently "liberated," are, in their different ways, casualties of the ongoing sex war: in Gems' terms, "an indictment of our age". Dusa embodies maternal instincts; Fish evokes politically conscious feminism and socialism; Stas represents sexual stereotyping; Vi is the truculent teen. These images are also subverted, though, as Gems strives to show that each of the characters has her measure of strength and vulnerability, often residing in unexpected places.

And yet you may feel, ultimately, that Dusa, Fish, Stas and Vi looks considerably less radical in its position on gender than, say, the early 20th Century work of Githa Sowerby, whose Rutherford and Son and The Stepmother have both received accomplished revivals this year. The play's perspective on Fish's idealistic position – a vision of men and women "breaking moulds together" - is pessimistic, but that pessimism – cemented by an abrupt and inauthentic tragic final twist – feels pat and unearned at the end. This may be due to the rather sketchy, soapy elements in Gems' writing, and the fact that the play, while consistently lively, doesn't really go deep enough into its characters to make their dilemmas count as much as they might.

Despite these shortcomings, though, at its best Gems' play has the savour of its moment and shows vividly how the problems facing the four characters – dilemmas traditionally sidelined as "women's issues" – are in fact central to the texture of their daily lives. And Eastman's production succeeds in finding most of the writing's strengths, nicely managing its movements from merriment to melancholy. Vivid performances help, with Olivia Poulet's bustling but unravelling Fish, Emily Dobbs's strident Stas, Helena Johnson's Jane-Horrocks-in-Life-is-Sweet-channelling Vi, and Sophie Scott's harried Dusa working well to make the characters' shifts from conflict to camaraderie feel natural.

Katie Bellman's design - garish flowery wallpaper, a green sofa bed, Sexual Politics on the book-shelf – conjures place and period without fuss, while the production's use of the theatre's "real" window – which gets smoked out of, and shouted through – is a lovely touch.

But perhaps the most affecting and evocative element in Eastman's production is its use of music. A range of 70s folk, pop, rock and punk songs by female musicians are employed to augment and punctuate the scenes, accentuating themes and emotions in a subtle and moving way. In the loveliest, most sustained of these interludes, Scott's Dusa, left alone in the flat, responds to a piece of heartening news as Fleetwood Mac's "Landslide" lilts away on the stereo. Eastman can't make Gems' contrived climax work, but in such quiet, unstressed episodes, the production transmits the intimate moments in its characters' lives in a way that goes straight to the heart.

Dusa, Fish, Stas and Vi, at Finborough TheatreAlex Ramon reviews Dusa, Fish, Stas and Vi at the Finborough Theatre.3