3 drugs suitable for a d20 game -

Red Black Walnutrot
The Vial has a cylinder shape and the glass is yellow, it has horizontal ribbing texture. The liquid in the vial is red, it has no taste, and it has a swampy smell.
Addiction Rating: Negligible
Drug Delivery Ingestion
Satiation: 1 day Damage: 1d3-2 Dex (minimum 0)
Initial Effect: Exotic visions of incredible beauty enthrall the user for the next 1d20+10 minutes. During this time the user has a 50 percent chance to loose any action he attempts, as described in the bestow curse spell.
Secondary Effect: The user becomes numbed to pain for 1d4 hours, immune to pain-induced penalties (such as from a symbol of pain).
Side Effects: Feelings of intense pleasure last for 1d4 hours.
Overdose: If more than one dose is taken in a 24-hour period, the user immediately takes 2d6 points of damage and the side effect is doubled.
Save: Fortitude (DC 3)
Cost: 195 gp
CR: 1
Distilled Smoketree Wine
The Vial has a cylinder shape and the glass is greenish yellow, it has bumps texture. The liquid in the vial is colorless, it has no taste, and it has a dusty smell.
Addiction Rating: Negligible
Drug Delivery Injury
Satiation: 1 day Damage: 1d3-2 Dex (minimum 0)
Initial Effect: 1 point of temporary Charisma damage
Secondary Effect: As a move-equivalent action, the user may focus his attention upon a particular creature. If he follows that action with an attack against the creature, he gains a +4 competence bonus on the attack roll. This ability lasts 10 minutes.
Side Effects: Mild euphoria and fierce confidence while the drug is in effect.
Overdose: Taking a second dose before the first has worn off causes the user to be nauseated for 1d4 x 10 minutes.
Save: Fortitude (DC 4)
Cost: 155 gp
CR: 1
Silverbell Bane
The Vial has a coffin shape and the glass is magenta, it has hobnails texture. The liquid in the vial is ivory, it taste like sweet onions, and it has a noxious smell.
Addiction Rating: Medium
Drug Delivery Inhaled
Satiation: 5 days Damage: 1d4 Dex, 1d4 Wis
Initial Effect: Exotic visions of incredible beauty enthrall the user for the next 1d20+10 minutes. During this time the user has a 50 percent chance to loose any action he attempts, as described in the bestow curse spell.
Secondary Effect: 1d4 points of temporary Intelligence damage and 1d3 points of temporary Wisdom damage
Side Effects: Feelings of intense pleasure last for 1d4 hours.
Overdose: If more than one dose is taken in a 12-hour period, the user takes 2d6 points of damage. Using it four or more times in a 24-hour period deals 4d6 points of damage and paralyzes the user for 2d4 hours.
Save: Fortitude (DC 15)
Cost: 1,070 gp
CR: 8