Is it true that Buddhism encourages the expansion of consciousness through the use of prohibited substances?

No, because Buddhism is a way of changing the internal biochemistry, and external substances "direct" to other "spectra of worlds" (there are better ones than nirvana)

In general, the word "expansion of consciousness" is incorrect to refer to Buddhism. It is believed that Buddha-nature is inherent in all beings. This can be realized by any creature, if external causes, including intoxicating substances, do not interfere. The Madyapana commandment (refusal to stupefy the mind) is not only about substances. If some actions lead to this, then they must be abandoned. For example, if some meditation practice or lifestyle causes uncontrollable addictions, then they need to be changed. It is not so much the external experience of interacting with the deterministic world that is valued, but the experience of self-knowledge, awareness of one's own nature, without connection with the world of cause and effect. External connections, compassion for others, knowledge, wisdom, patience are valued first of all as tools for revealing one's own original nature.

A person becomes a Buddhist after taking refuge. Taking refuge is accompanied by taking panca sila (five vows), one of which sounds in the Pali language as: Surā-meraya-majja-pamādaṭṭhānā veramaṇī sikkhāpadaṃ samādiyāmi. What does it mean in Russian: I accept the teaching rule to refrain from the use of intoxicants, leading to carelessness. The practitioner should develop awareness, mindfulness and concentration, which are impossible with the use of any intoxicants.

Absolutely not.
Any intoxication with tz. Buddhism is ts "Mara's machinations", no distinction is made between alcoholic intoxication or intoxication from some substances.