• World No2 says it is wrong to take a drug just for performance
• Murray also criticises his sponsor, Head, for extending Sharapova’s contract

Andy Murray says Maria Sharapova deserves to be banned for failing a test for a performance enhancing drug.

The world No2 also revealed he believes it is “wrong” for players to take any drug that is not specifically required for a medical condition and criticised the decision by his own racket manufacturer, Head, who earlier said it would be standing by the Russian and will extend her contract.

“It’s not up to me to decide the punishment, but if you’re taking performance enhancing drugs and you fail a drugs test, you have to get suspended,” Murray said at a press conference in Indian Wells, where he is playing in the BNP Paribas Masters.

Sharapova, the world’s highest-earning female athlete and one of the biggest sports stars on the planet, announced on Monday that she had failed a test for meldonium at the Australian Open. The former world No1 said she had been taking the drug legally for 10 years, but had not opened one of a number of email reminders from the ITF and WTA which told her it had been added to the Wada banned list on 1 January.

Murray said it was ethically wrong to take a drug just for performance. “I think taking a prescription drug that you don’t necessarily need, but just because it’s legal, that’s wrong, clearly. That’s wrong. If you’re taking a prescription drug and you’re not using it for what that drug was meant for, then you don’t need it, so you’re just using it for the performance enhancing benefits that drug is giving you. And I don’t think that that’s right.”

In typically forthright manner, Murray said he was not shocked by another drugs revelation, but cast doubt on the validity of Sharapova’s statement that she took meldonium for a series of health reasons. Meldonium, according to the manufacturer, improves blood circulation and is predominantly used a drug to combat heart issues.

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

Murray also said he was disappointed with a statement released by Head on Thursday that they are to stand by Sharapova and even 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 28-year-old said he thought it was good that it was “out in the open” but said Sharapova should have known what she was taking and whether it was banned. “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 but it’s almost kind of 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. “You check yourself to make sure, double check to make sure, that anything that’s going into your body is safe.

The Scot said he used protein shakes, energy gels and sports drinks but no longer takes any vitamin supplements, instead getting his vitamin intake through food. And he said tennis still needs to improve its efforts to combat drugs.

“I think all sports can do more,” he said. “It’s better than it was a few years ago, last year I got tested a lot but I’ve been tested twice so far this year, three months into the year, which is clearly not enough.”