Oregon Grape by Nature's Sunshine

POSSIBLY EFFECTIVE

• Psoriasis. Clinical research shows that applying a specific 10% Oregon grape extract cream (Relieva, Apollo Pharmaceutical) modestly decreases the severity of psoriasis and improves quality of life in patients with psoriasis when compared with placebo (854,857,14000,14333). One small clinical study shows that this specific cream might be as effective as calcipotriene (Dovonex) cream for some patients (14000).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Atopic dermatitis (eczema). Preliminary clinical research shows that applying a specific Oregon grape extract cream (Relieva) for 12 weeks improves the severity and area of eczema when compared to baseline in adult patients with atopic dermatitis (67370). The validity of this finding is limited by the lack of a comparator group. In contrast, applying a combination of Oregon grape, heart's ease, and gotu kola extracts for 4 weeks does not improve eczema when compared with a base cream, although there appears to be improvement in eczema for skin exposed to cold weather (67372). More evidence is needed to rate Oregon grape for this use.

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LIKELY SAFE ...when used orally in amounts commonly found in food.

POSSIBLY SAFE ...when used topically and appropriately (854,856,857,14000,14333). A specific 10% Oregon grape cream (Relieva, Apollo Pharmaceutical) has been used with apparent safety in studies lasting up to 12 weeks (14000,14333). There is insufficient reliable information available about the safety of Oregon grape when used orally in medicinal amounts.

CHILDREN: LIKELY UNSAFE
when used orally in newborns. The berberine constituent of Oregon grape can cause kernicterus in newborns, particularly preterm neonates with hyperbilirubinemia (2589).

PREGNANCY: LIKELY UNSAFE
when used orally. Berberine is thought to cross the placenta and may cause harm to the fetus. Kernicterus has developed in newborn infants exposed to berberine (2589).

LACTATION: LIKELY UNSAFE
when used orally. Berberine and other harmful constituents can be transferred to the infant through breast milk (2589).

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ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D In vitro and in vivo research suggests that berberine, a constituent of Oregon grape, can inhibit platelet aggregation (33660,33694). Theoretically, Oregon grape might have additive effects when used with anticoagulant and antiplatelet drugs and increase the risk of bleeding.  Details Some anticoagulant and antiplatelet drugs include aspirin, cilostazol (Pletal), clopidogrel (Plavix), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, ticlopidine (Ticlid), and others.

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = A Clinical research suggests that berberine, a constituent of Oregon grape, can lower blood glucose levels (20579,34247,34265,34282). Theoretically, Oregon grape might have additive effects when used with antidiabetes drugs and increase the risk of hypoglycemia.  Details Some antidiabetes drugs include glimepiride (Amaryl), glyburide (Diabeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), and others.

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Animal research suggests that berberine, a constituent of Oregon grape, can have hypotensive effects (33692,34308). Also, an analysis of clinical evidence suggests that taking berberine in combination with amlodipine (Norvasc) can lower systolic and diastolic blood pressure when compared with taking amlodipine alone (91956). Theoretically, taking Oregon grape along with antihypertensive drugs might have additive effects when used with antihypertensive drugs and increase the risk of hypotension.  Details Some antihypertensive drugs include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), amlodipine (Norvasc), hydrochlorothiazide (HydroDIURIL), furosemide (Lasix), and many others.

CNS DEPRESSANTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Animal research suggests that berberine, a constituent of Oregon grape, can have sedative effects (13519,33650,33664,33692). Theoretically, use of Oregon grape along with CNS depressants might increase the risk of additive therapeutic and adverse effects.  Details Some CNS depressants are benzodiazepines, pentobarbital (Nembutal), phenobarbital (Luminal), secobarbital (Seconal), thiopental (Pentothal), fentanyl (Duragesic, Sublimaze), morphine, propofol (Diprivan), and others.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Preliminary clinical evidence suggests that berberine, a constituent of Oregon grape, can inhibit cytochrome P450 2C9 (CYP2C9) (34279). Theoretically, taking Oregon grape with drugs metabolized by CYP2C9 might increase drug levels and potentially increase the risk of adverse effects.  Details Some drugs metabolized by CYP2C9 include celecoxib (Celebrex), diclofenac (Voltaren), fluvastatin (Lescol), glipizide (Glucotrol), ibuprofen (Advil, Motrin), irbesartan (Avapro), losartan (Cozaar), phenytoin (Dilantin), piroxicam (Feldene), tamoxifen (Nolvadex), tolbutamide (Tolinase), torsemide (Demadex), and S-warfarin (Coumadin).

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B In vitro research and preliminary clinical evidence suggest that berberine, a constituent of Oregon grape, can inhibit cytochrome P450 2D6 (CYP2D6) (21117,34279,34297). Theoretically, taking Oregon grape with drugs metabolized by CYP2D6 might increase drug levels and potentially increase the risk of adverse effects.  Details Some drugs metabolized by CYP2D6 include amitriptyline (Elavil), codeine, desipramine (Norpramin), flecainide (Tambocor), haloperidol (Haldol), imipramine (Tofranil), metoprolol (Lopressor, Toprol XL), ondansetron (Zofran), paroxetine (Paxil), risperidone (Risperdal), tramadol (Ultram), venlafaxine (Effexor), and others.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D In vitro research and preliminary clinical evidence suggest that berberine, a constituent of Oregon grape, moderately inhibits cytochrome P450 3A4 (CYP3A4) (13524,21114,34279,34297). Theoretically, taking Oregon grape with drugs metabolized by CYP3A4 might increase drug levels and potentially increase the risk of adverse effects.  Details Some drugs metabolized by CYP3A4 include lovastatin (Mevacor), clarithromycin (Biaxin), indinavir (Crixivan), sildenafil (Viagra), triazolam (Halcion), and numerous others. Use European barberry cautiously or avoid in patients taking these drugs.

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General ...Orally, no adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted. Topically, Oregon grape can cause itching, burning, skin irritation, and allergic reactions (854,14000).

Dermatologic ...Topically, Oregon grape can cause itching, burning, and skin irritation (854,14000).

Immunologic ...Topically, Oregon grape can cause allergic reactions (854,14000).

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