Andy Murray criticises own sponsors Head for supporting Maria Sharapova in drugs row

The former world number one women's tennis player, will be provisionally suspended starting March 12, the International Tennis Federation (ITF) has said after she tested positive for meldonium in January. She could be suspended for up to four years.

A number of sponsors have already distanced themselves from the Russian, including Nike and Porsche.

But Head - Murray's racket sponsor - had offered its full support to Sharapova in a seven point statement.

Murray said it was wrong to back Sharapova by announcing it plans to extend her contract.

“I think it’s a strange stance given everything that’s happened the last few days,” he said. “I don’t really know what else to say on that, but that’s not something I believe.

"I think at this stage it’s important really to get hold of the facts and let things play out, like more information coming out before making a decision to extend the contract like that, in my view. I personally wouldn’t have responded like that.”

The Russian tennis star says she has been taking the drug, which was added to the World Anti-Doping Agency's banned list on January 1, for health reasons for the past 10 years due to a family history of heart issues and diabetes.

Head released a statement after Sharapova's announcement saying it was “proud” of its relationship with Sharapova and described her as “a role model and woman of integrity”.

It said: “Head is proud to stand behind Maria, now and into the future and we intend to extend her contract. We look forward to working with her and to announcing new sponsorships in the weeks and months ahead. Maria may have made a mistake but she has earned the benefit of the doubt and we are extending it to her.”

Head’s chairman and chief executive, John Eliasch, set out the reasons for standing by Sharapova, saying: “Although it is beyond doubt she tested positive for the use of a Wada [World Anti-Doping Agency] banned substance, the circumstantial evidence is equally beyond doubt the continued use of meldonium after Jan 1st, 2016 in the dosages she had been recommended, which were significantly short of performance-enhancing levels, was a manifest error by Maria.

“In the absence of any evidence of any intent by Maria of enhancing her performance or trying to gain an unfair advantage through the use of mildronate, we further conclude this falls into the category of ‘honest’ mistakes.”

“We also know that for more than a decade, Maria Sharapova has been a role model and woman of integrity who has inspired millions of fans around the world to play and watch tennis. We look forward to many more years of working with Maria.”

Murray said he had been looking into the issue since Sharapova announced her news in a press conference on Monday and was sceptical.

He said she should have known what she was putting into her body, and whether it was legal.

“Some people put a lot of trust in the team around them so it’s hard to say what’s the right thing for everyone,” he said. “But it’s almost part of her job to know everything that’s going into her body and not just rely on what a doctor is saying or a physio is saying,” he said.

Meldonium is cheap and available over the counter without a prescription in some eastern European countries, where it is marketed as Mildronate by the Latvian pharmaceutical firm Grindeks.

The drug, originally developed by scientists at the Latvian Institute of Organic Synthesis, is not licensed by two of the world's biggest medicines regulators: the Food and Drug Administration (FDA) in the United States where Sharapova trains, and the EU's European Medicines Agency.

Meldonium also has the ability to adjust the body's use of energy, stimulating glucose metabolism and also helping to clear fatty build-up in the arteries - and could also have a positive effect on stamina and endurance in athletes.

Murray added: “I read that 55 athletes have failed tests for that substance since January 1. You just don’t expect high level athletes at the top of many sports to have heart conditions.”

Several athletes has tested positive for it in 2016, including 1500m world champion Abeba Aregawi, 2015 Tokyo Marathon winner Endeshaw Negesse and Russian ice dancer Ekaterina Bobrova.

Thirteen medallists from the 2015 European Games in Baku were also found to have been taking meldonium.

Grindeks marketing material says: "Due to its unique mechanism of action Mildronate®, depending on the prescribed dose, is widely used for the treatment of different heart and vascular diseases, as well as for the improvement of work capacity of healthy people at physical and mental overloads and during rehabilitation period. "