Drug Interactions between hydroxychloroquine and pyrimethamine
This report displays the potential drug interactions for the following 2 drugs:
- hydroxychloroquine
- pyrimethamine
Interactions between your drugs
pyrimethamine hydroxychloroquine
Applies to: pyrimethamine and hydroxychloroquine
MONITOR: Hydroxychloroquine (HCQ) can lower the seizure threshold and co-administration with other antimalarials known to lower the seizure threshold may theoretically increase this risk. While antimalarial product labels discuss this potential risk, available data involving HCQ or other antimalarial drugs and the risk of seizures are limited to case reports and speculation. Data surrounding the risk of seizures with concurrent antimalarial use are unavailable.
MANAGEMENT: Caution and closer monitoring for the development of seizures is recommended if coadministration of hydroxychloroquine with other seizure-threshold lowering antimalarials is required. In addition, patients with a history of epilepsy should be advised about the risk of antimalarial-induced seizures. Alternative anti-malarial agents may be required. Local treatment guidelines should be consulted.
References (5)
- (2024) "Product Information. Hydroxychloroquine Sulfate (hydroxychloroquine)." Dr. Reddy's Laboratories Inc
- (2023) "Product Information. Plaquenil (hydroxychloroquine)." Sanofi-Aventis Canada Inc
- (2024) "Product Information. Quinoric (hydroxychloroquine)." Bristol Laboratories Ltd
- (2024) "Product Information. Hydroxychloroquine (GH) (hydroxychloroquine)." Generic Health Pty Ltd
- (2023) "Product Information. HIDROXICLOROQUINA RATIOPHARM (hidroxicloroquina)." RATIOPHARM ESPANA S.A.
Drug and food interactions
hydroxychloroquine food
Applies to: hydroxychloroquine
GENERALLY AVOID: Theoretically, grapefruit and grapefruit juice may increase the plasma concentrations of hydroxychloroquine or chloroquine and the risk of toxicities such as QT interval prolongation and ventricular arrhythmias. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruit. Following coadministration with cimetidine, a weak to moderate CYP450 3A4 inhibitor, a 2-fold increase in chloroquine exposure occurred. Since chloroquine and hydroxychloroquine have similar structures and metabolic elimination pathways, a similar interaction may be observed with hydroxychloroquine. In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.
ADJUST DOSING INTERVAL: Administration with food or milk may reduce the incidence of hydroxychloroquine-related gastrointestinal adverse effects.
MANAGEMENT: Although clinical data are lacking, it may be advisable to avoid the consumption of grapefruit, grapefruit juice, and any supplement containing grapefruit extract during hydroxychloroquine or chloroquine therapy. Hydroxychloroquine should be administered with food or milk to reduce the occurrence of gastrointestinal upset.
References (5)
- (2024) "Product Information. Hydroxychloroquine Sulfate (hydroxychloroquine)." Dr. Reddy's Laboratories Inc
- (2023) "Product Information. Plaquenil (hydroxychloroquine)." Sanofi-Aventis Canada Inc
- (2024) "Product Information. Quinoric (hydroxychloroquine)." Bristol Laboratories Ltd
- (2024) "Product Information. Hydroxychloroquine (GH) (hydroxychloroquine)." Generic Health Pty Ltd
- (2023) "Product Information. HIDROXICLOROQUINA RATIOPHARM (hidroxicloroquina)." RATIOPHARM ESPANA S.A.
Therapeutic duplication warnings
Therapeutic duplication is the use of more than one medicine from the same drug category or therapeutic class to treat the same condition. This can be intentional in cases where drugs with similar actions are used together for demonstrated therapeutic benefit. It can also be unintentional in cases where a patient has been treated by more than one doctor, or had prescriptions filled at more than one pharmacy, and can have potentially adverse consequences.
Antimalarials
Therapeutic duplication
The recommended maximum number of medicines in the 'antimalarials' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'antimalarials' category:
- hydroxychloroquine
- pyrimethamine
Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.
See also
Drug Interaction Classification
Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. | |
No interaction information available. |
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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