- Valproic acid: is a substrate for CYP 450 2C19 isoenzyme and an inhibitor of CYP 450 2C9, 2D6, and 3A3/4 (weak). It increases amitriptyline/nortriptyline, phenytoin, diazepam, and phenobarbital levels.
- Concomitant phenytoin, phenobarbital, topiramate, meropenem, and carbamazepine may decreasevalproic acid levels. Amitriptyline or nortriptyline may increase valproic acid levels. May interfere with urine ketone and thyroid tests.
- Valproic acid and divalproex should not be used in pregnant women. Increased risk of neural tube defects, decreased child IQ scores, craniofacial defects, and cardiovascular malformations have been reported in babies exposed to valproic acid and divalproex sodium
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oxcarbazepine:Clinically significant hyponatremia may occur; generally seen within first 3 mo of therapy.
May also cause headache, dizziness, drowsiness, ataxia, fatigue, nystagmus, urticaria,diplopia, abnormal gait, and GI discomfort. About 25% to 30% of patients with
carbamazepine hypersensitivity will experience a cross-reaction with oxcarbazepine. Serious dermatologic reactions (Stevens-Johnson syndrome and TEN), multiorgan hypersensitivity reactions, bone marrow depression, pancreatitis, folic acid deficiency, hypothyroidism, rare
cases of anaphylaxis and angioedema, and suicidal behavior or ideation have been reported. - Inhibits CYP 450 2C19 and induces CYP 450 3A4/5 drug–metabolizing enzymes. Carbamazepine,cyclosporine, phenobarbital, phenytoin, valproic acid, and verapamil may decrease oxcarbazepine levels. Oxcarbazepine may increase phenobarbital and phenytoin levels. Oxcarbazepine can decrease effects of oral contraceptives, felodipine, and lamotrigine.
- amoxycillin:Renal elimination. Adjust dose in renal failure ). Serum levels about twice those achieved with equal dose of ampicillin. Fewer GI effects but otherwise similar to
ampicillin. Side effects: rash and diarrhea. Rash may develop with concurrent EBV infection.May increase warfarin’s effect by increasing INR - amoxy clavulunic acid:Clavulanic acid extends the activity of amoxicillin to include β-lactamase–producing strains of
Haemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae, and some Staphylococcus aureus and may increase the risk for diarrhea. See Amoxicillin for additional
comments. Adjust dose in renal failure . - Contraindicated in patients with a history of cholestatic jaundice/hepatic dysfunction associated with amoxicillin–clavulanic acid.
- Drug interactions
Superintendent, ICH.