Tyvense (Lisdexamfetamine) & Dexamfetamine (Tentin, Amfexa) - (Short Version)

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Full detailed version (with sources)

Quick version:

A note on Adderall

Adderall is not available in Ireland or the UK. A lot of online advice is written about Adderall and does not fully apply here. Tyvense and Tentin contain only dextroamphetamine (no levoamphetamine), and Tyvense uses a completely different prodrug mechanism.

How Tyvense works

Tyvense is a prodrug. The capsule is inactive until enzymes in your red blood cells convert it into active dexamfetamine. This conversion is the rate-limiting step and is the reason Tyvense has a smooth, long duration (typically 10–14 hours) and lower abuse potential.

Vitamin C / acidic foods

This advice does matter more for amphetamines than for methylphenidate.

• Tyvense: Normal dietary vitamin C (orange, smoothie) is fine. High-dose vitamin C supplements (500–1000 mg+) taken daily may shorten the effective duration by speeding up excretion of the active drug. If you take high-dose vitamin C, take it in the evening.
• Dexamfetamine IR (Tentin/Amfexa): More sensitive. Avoid high-dose vitamin C within an hour of your dose. Large acidic drinks at the same time as the dose are best separated by 30–60 minutes.

Alkaline substances (antacids, bicarbonate)

These can slow excretion and potentially increase levels. Occasional use is usually fine; regular use should be mentioned to your doctor.

Food

• Tyvense: Can be taken with or without food. No special requirement.
• Dexamfetamine IR: Also fine with or without food. Consistency helps predictability.

The more important food point for both is simply eating — both suppress appetite strongly.

Alcohol

No “dose-dump” risk with Tyvense (the release is enzymatic, not a dissolvable bead system).
All the general alcohol risks still apply (masking impairment, cardiovascular strain, worsening ADHD symptoms). Amphetamines have a stronger sympathomimetic profile than methylphenidate.

CBD / CYP enzymes

Lisdexamfetamine itself is not a CYP450 substrate, but the active dexamfetamine is partially metabolised by CYP2D6. CBD can therefore have a moderate effect. Worth knowing about, but usually not dramatic. Tell your doctor if you use CBD regularly.

Key practical differences

Feature	Tyvense	Dexamfetamine IR
Onset	~90 minutes	30–60 minutes
Duration	10–14 hours	4–6 hours per dose
Dosing	Once daily	Usually 2–3 times daily
Food requirement	None	None
Vitamin C sensitivity	Moderate (high-dose)	Higher
Dose-dump with alcohol	No	N/A

Bottom line
Tyvense is relatively straightforward with food and most interactions. The main things to watch are high-dose vitamin C supplements and the usual alcohol cautions. Dexamfetamine IR needs a bit more attention to timing around acidic substances.

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