St Johns Wort

St. John’s Wort is a herb with the botanical name of Hypericum
perforatum.

DESCRIPTION

St. John’s wort was named after St John’s Day which falls on
June 24, the approximate flowering season in the northern
hemisphere. The plant is seen growing wild beside roadsides and
hedges in Britain, Europe and Asia. It reaches up to a metre in
height and has pale green leaves with black dots on the lower
surface. The flowers are bright yellow with five petals. The whole
plant above the ground is harvested when the plant is just
flowering. The herb has a bitter astringent taste and an aromatic
odour. 

This herb contains many chemicals including a red pigment known as
hypericin, as well as flavonoids, phenols, tannins and volatile
oil.

INTERACTIONS

Herbal supplements can alter the effects of certain drugs,
including prescription medications. Always tell your Doctor about
any prescription medications, non-prescription medications, herbs
or other dietary supplements you are taking. 

• St. John’s Wort can increase the rate of breakdown of a large
  number of prescription medications by changing the substances
  (enzymes and transporters) that metabolise drugs. Contact your
  Doctor immediately if you experience any changes in the effects of
  your medications.
• St. John’s Wort should not be used by people taking any of the
  SSRI’s (selective serotonin re-uptake inhibitors), which are used
  for the treatment of anxiety and mood disorders such as depression.
  There have been reports of interactions between St. John’s Wort and
  paroxetine, trazodone, sertraline as well as the serotonin-receptor
  blocker nefazodone (another anti-depressant drug). Combining any of
  these drugs has produced symptoms of serotonin excess (serotonin
  syndrome), which can cause euphoria, drowsiness, sustained rapid
  eye movement, overreaction of the reflexes, clumsiness,
  restlessness, feeling drunk and dizzy, muscle contraction and
  relaxation in the jaw, sweating, intoxication, muscle twitching,
  rigidity, high body temperature, mental status changes (including
  confusion and hypomania – a “happy drunk” state), shivering,
  diarrhoea, loss of consciousness and death. St. John’s Wort may
  decrease the effects of the tricyclic antidepressant drugs
  amitriptyline and nortriptyline .
• St. John’s Wort should not be used with digoxin (for the
  treatment of heart failure), as this herb reduces the effectiveness
  of digoxin in the body. 
• St. John’s Wort should not be used by people taking warfarin
  (an anticoagulant medication), as it may decrease the blood levels
  of this drug, thus reducing its medical effects in the body.
• St. John’s Wort may interact with monoamine oxidase inhibitor
  drugs, which are used for depression, as this herb may act in a
  similar manner in the body to these antidepressant
  medications. 
• St. John’s Wort should not be used by people taking
  benzodiazepine drugs (e.g. nitrazepam), which are prescribed for
  insomnia, anxiety and panic attacks This herb may act in a similar
  manner to these drugs within the brain 
• St. John’s Wort should not be used with theophylline (a drug
  that is prescribed for asthma and other lung conditions such as
  emphysema and chronic bronchitis) as it may reduce the beneficial
  effects of this drug. 
• St. John’s Wort can interact with the oral contraceptive pill
  by increasing its rate of breakdown, thus causing breakthrough
  bleeding. 
• St. John’s Wort can also reduce the blood levels of cyclosporin
  (a drug that reduces the activity of the immune system and is
  prescribed for autoimmune diseases such as rheumatoid arthritis,
  severe psoriasis and to prevent organ transplant rejection) and
  indinavir (an anti-viral drug), thus reducing the beneficial
  effects of these drugs.
• St. John’s Wort may reduce the effects of the antihistamine
  drug fexofenadine .
• St. John’s Wort may decrease the effects of the anti-viral drug
  nevirapine .
• St. John’s Wort may decrease the effects of the calcium channel
  blocker nifedipine, used to treat hypertension and angina.
  People 
• St. John’s Wort can interact with anaesthetics used when people
  have surgery. People who are taking St. John’s Wort and who are
  going to have surgery should tell their Doctor well before surgery,
  as they will need to discontinue use of St. John’s Wort some days
  before surgery.
• St. John’s Wort may reduce the effects of the
  cholesterol-lowering drug simvastatin .

MEDICAL USE

Always consult your Health Professional to advise you on
dosages and any possible medical interactions. 

St John’s Wort has been used traditionally for its effects on the
nervous system. The herb has a mild sedative and restorative effect
on the nervous system and may be useful in cases of anxiety,
irritability, neuralgia, nerve damage or injury, nervous tension
and general nervous debility. 

DEPRESSION

St John’s Wort has been found to be beneficial in the health
management of mild depression. It may improve mental capacity,
sleep quality and headaches in some people who suffer from
depression. The herb is prescribed four times as often as
fluoxetine in Germany. 

VIRUS AND BACTERIA

Hypericin is an inactivator of infectious viruses in blood and
may be useful in the management of some viral infections such as
herpes, cold sores, some types of colds, and perhaps Hepatitis C.
St John’s Wort may also possess antibacterial properties.
Antibacterial substances with resistance to, and activity against,
strains of bacteria such as Staphylococcus aureus, have been found
in St John’s Wort.

WOUND HEALING

St John’s Wort has an anti-inflammatory action and helps to
stimulate the growth and repair of skin tissue. St John’s Wort oil
or ointment has a long history of traditional use in the treatment
of wounds and painful skin conditions such as bruises and shingles.
For more information, see the St John’s Wort (External Use)
topic.

PROPERTIES

Antidepressant and sedative, antiviral, antibacterial,
anti-inflammatory, wound healing and astringent.

NOTES

• The effects of St. John’s Wort have not been well studied, so
  its safety for the developing child has not been established. For
  this reason, it is recommended that women who are pregnant or
  breastfeeding avoid the use of St. John’s Wort.
• It is extremely important to tell your Doctor and Pharmacist if
  you are taking St John’s Wort.
• In rare cases, St John’s Wort has caused increased nerve
  sensitivity, including tingling sensations and increased
  sensitivity to heat and cold. 
• Possible side effects of St John’s Wort include stomach upset,
  allergic reactions, confusion, dizziness, tiredness, dry mouth and
  photosensitivity.
• In Ireland, products containing St. John’s Wort are only
  available on medical prescription.