Fenoxybenzamin - en alfa-blockerare
Granskad av Sid DajaniSenast uppdaterad av Michael Stewart, MRPharmSSenast uppdaterad 19 jan 2025
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Adults will normally start with one capsule a day. This dose may then be increased over the next few days.
It is common to feel dizzy or light-headed initially. This should soon settle.
You may be given other medicines to take alongside phenoxybenzamine.
Överblick
Phenoxybenzamine capsules are used to treat high blood pressure caused by a tumour called phaeochromocytoma.
It works by blocking certain sites on your blood vessels to reduce high blood pressure.
It is sometimes used as a short-term treatment before surgery to remove the tumour.
Take your capsules exactly as your doctor tells you, usually starting with a small dose that is gradually increased.
It can cause dizziness or faintness, especially when standing up; get up slowly to help.
About phenoxybenzamine
Typ av medicin | An alpha-adrenoceptor blocker (also called an alpha-blocker) |
Används för | High blood pressure caused by phaeochromocytoma |
Tillgänglig som | Kapslar |
Phaeochromocytoma is a tumour of your adrenal glands. With phaeochromocytoma, large quantities of chemicals are released from your adrenal glands, which narrow (constrict) your blood vessels. This causes episodes where your blood pressure increases significantly.
The treatment of choice for phaeochromocytoma is removal of the tumour by surgery. Phenoxybenzamine is sometimes prescribed as a short-term option in preparation for the surgery. It works by blocking sites on your blood vessels, known as alpha receptors. This blocking action reduces your högt blodtryck.
Before taking phenoxybenzamine
Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking phenoxybenzamine it is important that your doctor knows:
Om du är gravid eller ammar.
If you have problems with the way your kidneys work.
If you have heart disease, or if you have recently had a heart attack.
If you have ever had a stroke.
Om du har en sällsynt ärftlig blodsjukdom som kallas porfyri.
Om du någonsin har haft en allergisk reaktion mot en medicin.
Om du tar eller använder några andra läkemedel. Detta inkluderar alla läkemedel du tar som finns att köpa utan recept, samt växtbaserade och komplementära läkemedel.
How to take phenoxybenzamine
Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about phenoxybenzamine, and will also provide you with a full list of side-effects which you could experience from taking it.
When you start the treatment, your doctor will give you a small dose (one capsule a day) and will then gradually increase your dose over the next few days as necessary. Take phenoxybenzamine capsules exactly as your doctor tells you to. The directions will be printed on the label of the pack of capsules to remind you about what the doctor said to you.
Try to take your doses at the same time of day each day, as this will help you to remember to take them regularly. You can take phenoxybenzamine either before or after a meal. Swallow the capsule with a drink of water.
If you forget to take a dose at your usual time, take it as soon as you remember. If you do not remember until the following day, leave out the forgotten dose from the previous day and take the dose that is due as normal. Do not take two doses at the same time to make up for a missed dose.
Få ut det mesta av din behandling
Keep your regular appointments with your doctor. This is so your doctor can check on your progress.
If you buy any medicines, check with a pharmacist that they are suitable for you to take alongside phenoxybenzamine.
Can phenoxybenzamine cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains the most common ones associated with phenoxybenzamine. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any continue or become troublesome.
Phenoxybenzamine side-effects | Vad kan jag göra om jag upplever detta? |
Feeling dizzy or faint, especially when you get up from a lying or sitting position | Getting up more slowly may help. If you begin to feel dizzy, lie down so that you do not faint, then sit for a few moments before standing. Do not drive and do not use tools or machines while affected |
Feeling tired, blocked nose, eyesight problems, ejaculatory problems, a fast heartbeat, stomach upset, diarrhoea | Om något av dessa blir besvärligt, tala med din läkare |
If you experience any other symptoms which you think may be due to the capsules, speak with your doctor or pharmacist for further advice.
How to store phenoxybenzamine
Förvara alla läkemedel utom räckhåll och synhåll för barn.
Förvara på en sval, torr plats, borta från direkt värme och ljus.
Viktig information om alla läkemedel
Viktig information om alla läkemedel
Ta aldrig mer än den föreskrivna dosen. Om du misstänker att du eller någon annan kan ha tagit en överdos av denna medicin, gå omedelbart till akutmottagningen på ditt lokala sjukhus. Ta med behållaren, även om den är tom.
Denna medicin är för dig. Ge den aldrig till andra människor även om deras tillstånd verkar vara detsamma som ditt.
If you are due to have an operation or dental treatment, please tell the person carrying out the treatment which medicines you are taking.
Behåll inte föråldrade eller oönskade mediciner. Ta dem till ditt lokala apotek som kommer att ta hand om dem åt dig.
Om du har några frågor om denna medicin, fråga din apotekare.
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Vanliga frågor
What is phenoxybenzamine used for?
Phaeochromocytoma is a tumour of your adrenal glands. With phaeochromocytoma, large quantities of chemicals are released from your adrenal glands, which narrow (constrict) your blood vessels. This causes episodes where your blood pressure increases significantly.
The treatment of choice for phaeochromocytoma is removal of the tumour by surgery. Phenoxybenzamine is sometimes prescribed as a short-term option in preparation for the surgery. It works by blocking sites on your blood vessels, known as alpha receptors. This blocking action reduces your high blood pressure.
What should I do if I forget to take a dose of phenoxybenzamine?
If you forget to take a dose at your usual time, take it as soon as you remember. If you do not remember until the following day, leave out the forgotten dose from the previous day and take the dose that is due as normal. Do not take two doses at the same time to make up for a missed dose.
What should I tell my doctor before starting phenoxybenzamine?
Before you start taking phenoxybenzamine it is important that your doctor knows if you are pregnant or breastfeeding, have problems with kidney function, have heart disease or have recently had a heart attack, have ever had a stroke, have a rare inherited blood disorder called porphyria, have ever had an allergic reaction to a medicine, or are taking any other medicines, including over-the-counter or herbal remedies.
How should I store phenoxybenzamine capsules?
Keep all medicines out of the reach and sight of children. Store phenoxybenzamine in a cool, dry place, away from direct heat and light.
Can I take other medicines, including over-the-counter ones, with phenoxybenzamine?
If you buy any medicines, including those available without a prescription, you should check with a pharmacist to ensure they are suitable for you to take alongside phenoxybenzamine. It's important to also inform your doctor about any other medicines you are taking, including herbal and complementary medicines.
Vidare läsning och referenser
- Manufacturer's PIL, Phenoxybenzamine 10 mg Capsules; Advanz Pharma, The electronic Medicines Compendium. Dated September 2023.
- Mediciner Komplett BNF 89:e Utgåvan; Brittiska Läkarföreningen och Kungliga Farmaceutiska Sällskapet i Storbritannien, London.
Om författarenVisa fullständig biografi

Michael Stewart, MRPharmS
Ansvarig för granskning av medicinbroschyrer – Konsult, Apotekare
BPharm (Hons), MRPharmS
Michael är en apotekare som arbetar i Midlands och South Yorkshire med mer än 20 års erfarenhet av att ge råd om läkemedel och medicinska tillstånd. Han har en stark bakgrund inom vårdutbildning och har producerat och levererat utbildningskurser för apoteksteam och personal inom vårdboenden, inklusive sjuksköterskor. Han har också bidragit till apoteksrådgivande styrelser för hantering av mindre allvarliga tillstånd i samhället.
Om recensenten

Sid Dajani
Sultan Dajani tog examen vid London School of Pharmacy 1994 och blev den yngsta valda medlemmen i Royal Pharmaceutical Society-rådet sedan dess grundande 1842.
Artikelhistorik
Informationen på denna sida är skriven och granskad av kvalificerade kliniker.
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Nästa granskning: 19 jan 2028
19 jan 2025 | Senaste versionen

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