Yes, Pharmacophobia is an absolutely cruel challenge, and IMO the most difficult by far.

Combined with Barren Land you lose the ability to heal from Waterskin and Sungrass.

Your main ways of healing would be:

• Dying and resurrecting with Ankhs (safe on boss levels)
• Well of Health, it also cures starvation, so it is a lifesaver!
• Passive health regen (when not hungry)
• Potion of Cleansing (Upgraded Potion of Purity) cures harmful effects such as starving, thus allowing for passive HP regen!
• Scroll of Lullaby (Once you are not starting)
• Leveling up gives you 5 extra hp
• Vampiric enchantment is very strong (life steal on hit)
• Eating Meat Pie boosts HP regen, healing for 25 HP or 9 HP when ‘On Diet’ challenge
• Class-specific ways, such as Warrior talents, Mage soul-mark, Dualist meditation and Challenge, etc.

On having less SoU, due to the ‘Faith is My Armor’ challenges armour is completely useless, so you invest the scrolls into wands, rings and weapons. In my run, I spent 4 upgrades on the wand of Fireblast, 3 on Whip and one on the Ring of Furur. I augmented my Cloth armor for evasion and together with Evasive Armor talent I had a decent chance to avoid hits. And used freerunning to kite enemies and kill them using the range of the Whip, Fireblasts also cripples when upgraded, which really helps. Early on I would use my cloak to create distance with enemies instead. Hope that helps :)