Migraine sufferers will have to wait a little longer for a convenient medication after the US Food and Drug Administration denied approval of an inhalable drug from the health care company Allergan.

On Wednesday, the FDA delivered its Complete Response Letter, CPL, to the company's application for the trial drug Levadex, a type of migraine medication they have fabricated into aerosol form.

A migraine entails an overpowering and seemingly endless headache that can be accompanied by nausea, vomiting, and intense sensitivity to light. The World Health Organization estimates that 300 million people around the world are affected by migraines.

Current migraine medications are available in nasal spray and injection form known as dihydroergotamine. Allergan's affiliating pharmaceutical laboratory, MAP Pharmaceutical Inc., was able to manufacture a more accessible option with Levadex.

In a letter explaining their reasoning, the FDA mentioned manufacturing issues regarding the canister the medication was packaged in.

The agency directed this concern to Exemplar Pharma LLC, the aerosol packaging company Allergan used to transfer the medication into canisters.

The company will await an investigation of Exemplar's facilities although it claims the FDA's concerns have already been resolved and that the agency has not had time for a follow-up inspection, Reuters reported.

Allergan previously marketed the migraine medication Botox back in 2010 when the FDA gave its approval for sale. The company expects that the agency will require revisions to this medication as well before the year is over.

In a public statement the company said, "Allergan is committed to vigorously address the concerns raised by the FDA in the CRL. Based on Allergan's current understanding of the FDA's CRL, the company estimates that the next FDA action will occur by the end of Q4 2013."