Periactin tablets contain the active ingredient cyproheptadine, which is a type of medicine called a sedating antihistamine.
What is it used for?
- Relieving the symptoms of allergic conditions such as hay fever, pet allergies, dust mite allergies, nettle rash (urticaria), food allergies and reactions to insect bites or medicines.
- Relieving the symptoms of a more serious allergic reaction called angioneurotic oedema, which causes swelling of the eyes, lips, tongue or throat.
- Relieving itching associated with chickenpox or eczema.
- Relieving migraine and vascular headaches.
How does it work?
- Periactin tablets contain the active ingredient cyproheptadine, which is a type of medicine called a sedating antihistamine.
- Histamine is a substance produced by the body as part of its defence mechanisms. It is stored in cells called mast cells, in almost all tissues of the body.
How do I take it?
- For relieving the symptoms of allergies, adults, adolescents and children aged 14 years and over should take one Periactin tablet three times a day to start with. If this does not relieve symptoms the dose can be increased to up to a maximum of eight tablets in 24 hours. Elderly people should avoid taking this medicine.
- For relieving the symptoms of allergies, children aged 7 to 14 years can be given one tablet two or three times a day, depending on age and weight of the child. If necessary a further dose of one tablet can be given at bedtime. Do not give this age group more than four tablets in 24 hours.
- For relieving the symptoms of allergies, children aged 2 to 6 years can be given half a tablet two or three times a day. If necessary a further dose of half a tablet can be given at bedtime. Do not give this age group more than three tablets in 24 hours.
- To treat a migraine, adults should take one tablet when you first notice you are getting the migraine. Take another tablet if needed after 30 minutes. Then take one tablet every four to six hours to maintain relief if necessary. Do not take more than two tablets in any four to six hour period.
- The tablets can be taken either with or without food.
- Do not exceed the recommended dose.
- If symptoms persist despite treatment, seek medical advice from your doctor or pharmacist.
Use with caution in
- Children (who are also more prone to potential side effects).
- A condition called bronchiectasis, in which there is persistent and progressive widening of the airways due to lung infections or lung disease, such as cystic fibrosis.
- Men with an enlarged prostate gland (prostatic hypertrophy).
- People with raised pressure in the eye.
- Liver disease.
- People with cardiovascular disease.
- People with high blood pressure (hypertension).
- People with an overactive thyroid gland (hyperthyroidism).
- Hereditary blood disorders called porphyrias.
Not to be used in
- Children under two years of age.
- Elderly, weak or debilitated people.
- People who have taken a type of antidepressant called a monoamine oxidase inhibitor (MAOI, eg phenelzine, tranylcypromine or isocarboxazid) in the last 14 days.
- People having treatment for an asthma attack.
- People with a blockage of the opening from the stomach into the intestines (pyloro-duodenal obstruction).
- People with a peptic ulcer that is causing narrowing in the gut (stenosing peptic ulcer).
- People with a blockage of the drainage of urine out of the bladder (bladder neck obstruction) or difficulty passing urine (urinary retention), for example due to an enlarged prostate gland.
- Periactin tablets contain lactose and are not suitable for people with rare hereditary problems of galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption.
This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of this medicine for use during pregnancy has not been established. If you are pregnant you should not take this medicine without consulting your doctor for advice first. It should be used with caution during pregnancy, and only if the expected benefit to the mother is greater than any possible risk to the developing baby.
- It is not known if this medicine passes into breast milk. However, as it could potentially be harmful to a nursing infant, you should not take this medicine if you are breastfeeding. Seek further medical advice from your doctor.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
- Drowsiness or sleepiness (in many people this wears off after three to four days of treatment).
- Problems with co-ordination.
- Blurred or double vision.
- Difficulty passing urine (urinary retention).
- Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain.
- Dry mouth, nose or throat.
- Wheezing or difficulty breathing.
- Low blood pressure (hypotension).
- Awareness of your heartbeat (heart palpitations).
- Increased heart rate.
- Excitement in children.
- Difficulty sleeping (insomnia).
- Changes in appetite.
- Weight gain.
- Pins and needles sensations.
- Liver problems.
- Blood disorders.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
You should not use other antihistamines in combination with this medicine. Some cough and cold medicines contain antihistamines, so always check with your pharmacist before taking other medicines in combination with this one.
This medicine should not be used by people who have taken a type of antidepressant called a monoamine oxidase inhibitor (MAOI) in the last 14 days. This is because side effects such as blurred vision, dry mouth, drowsiness or constipation may be intensified by MAOIs. MAOIs include phenelzine, isocarboxazid and tranylcypromine. For more information ask your pharmacist.
There may be an increased risk of drowsiness and sedation if this medicine is taken with any of the following (which can also cause drowsiness):
- antipsychotics, eg haloperidol, chlorpromazine
- barbiturates, eg phenobarbital, amobarbital
- benzodiazepines, eg diazepam, temazepam
- other sedating antihistamines, eg hydroxyzine, promethazine, chlorphenamine
- sleeping tablets, eg zopiclone
- strong opioid painkillers, eg morphine, codeine, tramadol
- tricyclic antidepressants, eg amitriptyline, nortriptyline.
There may be an increased risk of side effects such as dry mouth, blurred vision, difficulty passing urine and constipation if cyproheptadine is taken with antimuscarinic medicines that can cause these type of side effects, such as the following:
- antimuscarinic medicines for Parkinson's symptoms, eg procyclidine, orphenadrine, trihexiphenidyl
- antimuscarinic medicines for urinary incontinence, eg oxybutynin, flavoxate, tolterodine, propiverine, trospium
- some antipsychotics, eg chlorpromazine, clozapine
- antispasmodics, eg hyoscine, atropine
- tricyclic antidepressants, eg amitriptyline, imipramine.
Due to its serotonin blocking action in the brain, cyproheptadine may possibly oppose the antidepressant effect of SSRI antidepressants such as fluoxetine, paroxetine or citalopram.
Cyproheptadine may oppose the effect of histamine (used to treat leukaemia) and is not recommended for people having this treatment.
Cyproheptadine may also oppose the effect of betahistine (used to treat Ménière's disease).