Hearing the ephedrine case, a special anti-narcotics court on Monday issued an arrest warrant for Ali Musa Gillani, the son of former Prime Minister Yousaf Raza Gillani.

Earlier in April, the court had indicted Gillani and 10 others in the ephedrine quota case which rocked the PPP government in March 2011.

The long-running case involves two Pakistani pharmaceutical companies, Berlex and Danas, that allegedly used political connections to obtain huge amounts of ephedrine and are suspected of diverting it to people in the drug trade who could have used it to make methamphetamine worth billions of dollars.

The companies have denied any wrongdoing, while Musa had earlier claimed that he was being involved in the ephedrine case on political basis and that he did not have any connection with it.

Explore: Ephedrine case: Firm paid Rs11m to Musa Gilani, says approver

Ali Musa Gillani was named as the accused in the case in 2012, when the Anti-Narcotics Force initially submitted a report before the Supreme Court (SC) formally naming Ali Musa Gillani and seven others for their alleged involvement in the scam.

Gillani was once arrested by ANF sleuths in 2012, right outside the SC premises. However, he was granted bail by the apex court.

What is ephedrine?

Ephedrine, along with pseudoephedrine, is one of the main ingredients in methamphetamine, a scheduled narcotic substance.

Explore: Europe frets as cartels turn to S. Asia for ephedrine

Drug cartels often look towards countries with weak regulations to facilitate their requirement for ephedrine.

According to Matt Nice of the Vienna-based International Narcotics Control Board, cartels look for a country with weak security and regulation “where you can obtain the chemicals because no one is paying attention, or it has never been a problem before.”

According to a UN report, published in 2015, "Increasing methamphetamine seizures and expert perception of high levels of methamphetamine tablet and crystalline methamphetamine use indicate the presence of a large and possibly expanding market in East and South-East Asia."

Methamphetamine, it is said, can be more valuable and addictive than heroine.