Wyo. Stat. § 7-13-904

(a) When sentence of death is imposed by the court in any criminal case, the punishment of death shall be executed by the administration of a continuous intravenous injection of a lethal quantity of an ultra-short-acting barbiturate, alone or in combination with a chemical paralytic agent and potassium chloride, or other equally effective substance or substances sufficient to cause death, until death is pronounced by a licensed physician according to accepted standards of medical practice. The sentence of death shall be executed within the time prescribed by law, unless, for cause shown, the court or governor extends the time. Administration of the injection does not constitute the practice of medicine.

(b) If the execution of the sentence of death as provided in subsection (a) of this section is held unconstitutional, the sentence of death shall be executed by the administration of lethal gas within the time prescribed by law unless for cause shown, the court or the governor extends the time.