What the FDA labels say about taking them together
Ritonavir and valproic acid
Ritonavir's FDA label of July 23, 2026 names valproic acid in its drug interactions section, and valproic acid's label names ritonavir too. The ritonavir label: “Anticonvulsants: divalproex, lamotrigine, phenytoin ↓ anticonvulsants A dose increase may be needed for these drugs when co-administered with ritonavir and therapeutic concentration monitoring is recommended for these …”
Check it at the source: the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.); the valproic acid FDA label on DailyMed (effective January 24, 2025, PAI Holdings, LLC dba PAI Pharma).
What does the ritonavir label say about valproic acid?
Ritonavir label, drug interactionsAnticonvulsants: divalproex, lamotrigine, phenytoin ↓ anticonvulsants A dose increase may be needed for these drugs when co-administered with ritonavir and therapeutic concentration monitoring is recommended for these anticonvulsants, if available.
Source: FDA drug label (Norvir), AbbVie Inc., effective July 23, 2026 (SPL set 2849298e-de6e-47bb-8194-56e075b33fc3), via openFDA; the full label on DailyMed
What does the valproic acid label say about ritonavir?
Valproic acid label, drug interactionsDrugs on Valproate Clearance Drugs that affect the level of expression of hepatic enzymes, particularly those that elevate levels of glucuronosyltransferases (such as ritonavir), may increase the clearance of valproate.
Source: FDA drug label (VALPROIC ACID), PAI Holdings, LLC dba PAI Pharma, effective January 24, 2025 (SPL set 7d5cb52e-37dd-4dfa-a6f4-09f9548846c6), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Ritonavir | Valproic acid | |
|---|---|---|
| Labeled for | HIV | Seizures and epilepsy, Migraine |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.607 per tablet 100 mg tablet | $0.243 per capsule 250 mg capsule |
| Shortage now | A presentation being discontinued | Listed; available |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once