DRUG/HERB INTERACTIONS GUIDE PHENTOLAMINE MESYLATE/I-1 85Oxytocin
(Development of high blood
pressure)
MAO INHIBITORS
Brewer's Yeast
(Increase in blood pressure)
Ginseng
(Combination increases chance for
headache, tremors, mania)
Ma-Huang
(Increases sympathomimetic
effects of ephedrine)
Scotch Broom
(Increased risk of hypertensive
crisis)
MATRICARIA RECUTITA
(See under German Chamomile)
MEDICATION AND FOOD THAT INCREASE
URIC ACID LEVELS
Alpine Cranberry
(Decreases effect of Alpine
Cranberry)
Uva-Ursi
(Decreases effect of herb)
MELALEUCEA VIRIDIFLORA
(See under Niauli)
METHYLXANTHINES
Digitalis
(Increases risk of cardiac
arrhythmias)
Digitalis Lanata
(Risk of cardiac arrhythmias)
Indian Squill
(Can increase the risk of cardie
arrhythmias when given
simultaneously with this herb)
Squill
(Increases risk of cardiac
arrhythmias)
MILK THISTLE
Haloperidol
(Silymarin in combination with
haloperidol causes a decrease in
lipid peroxidation)
Phenothiazines
(Silymarin in combination with
phenothiazines causes a decrease
in lipid peroxidation)
Phentolamine Mesylate
(Silymarin antagonizes the effect
of phentolamine)
Yohimbine Hydrochloride
(Silymarin antagonizes the effect
of yohimbine)
MORPHINE SULFATE
Yohimbe Bark
(Potentiates effects of morphine)
NALTREXONE HYDROCHLORIDE
Yohimbe Bark
(Potentiates Yohimbe side effects)
NERIUM OLEANDER
(See under Oleander)
NEUROLEPTICS
Rauwolfia
(Synergistic effect)
NIAULI
Drugs, unspecified
(Co-administration may result in
decreased effect of drugs that
undergo liver metabolism)
NIFEDIPINE
Senna
(Inhibits activity of Senna via
calcium channel blockade)
NON-STEROIDAL ANTI-INFLAMMATORY
DRUGS
Uva-Ursi
(Uva-Ursi may potentiate the
gastrointestinal irritation caused by
NSAIDs)
White Willow
(Use with caution; effect not
specified)
OTC STIMULANTS
Yohimbe Bark
(Potentiates hypertensive effect)
OAK
Alkaline Drugs
(Absorption of alkaline drugs may
be reduced or inhibited)
Alkaloids
(Absorption of alkaloids may be
reduced or inhibited)
OENOTHERA BIENNIS
(See under Evening Primrose)
OLEANDER
Calcium Salts
(Increased efficacy and side
effects when given simultaneously
with herb)Glucocorticoids
(Increased efficacy
effects when given
with herb)
Laxatives
(Increased efficacy
effects when given
with herb)
Quinidine
(Increased efficacy
effects when given
with herb)
Saluretics
(Increased efficacy
effects when given
with herb)and side
simultaneouslyand side
simultaneouslyand side
simultaneouslyand side
simultaneouslyORAL CONTRACEPTIVES
St. John's Wort
(Breakthrough bleeding has been
reported with concomitant use of
the herb with oral contraceptives)
OXYTOCIN
Ma-Huang
(Development of high blood
pressure)
PANAX GINSENG
(See under Ginseng)
PAPAYA
Warfarin Sodium
(Increased INR levels)
PAULLINIA CUPANA
(See under Guarana)
PAUSINYSTALIA YOHIMBE
(See under Yohimbe Bark)
PHENOTHIAZINES
Henbane
(Increased anticholinergic action)
Milk Thistle
(Silymarin in combination with
phenothiazines causes a decrease
in lipid peroxidation)
Wormwood
(Wormwood preparations should
not be administered with drugs
known to lower the seizure
threshold)
PHENTOLAMINE MESYLATE
Milk Thistle
(Silymarin antagonizes the effect
of phentolamine)