What is rizatriptan and how does it work?
Rizatriptan is a so-called serotonin receptor agonist: the active ingredient binds to the docking sites of the body’s own messenger substance serotonin (5-HT1 receptors) on blood vessels and nerve cells in the brain. As a result, the blood vessels, which are most likely dilated during a migraine attack, constrict.
In addition, the nerve cells secrete fewer messenger substances that otherwise mediate inflammation and pain. Rizatriptan thus counteracts the processes that physicians suspect are behind the symptoms of a migraine.
Absorption, breakdown and excretion
After ingestion, rizatriptan rapidly enters the blood via the intestines. The highest amount of the active ingredient in the blood is reached 60 to 90 minutes after ingestion in the case of tablets. For meltable tablets, the maximum amount of active ingredient is present in the blood about 30 to 60 minutes later. After two to three hours, half of it has been broken down. Rizatriptan is excreted mainly via the kidney.
What are the side effects of rizatriptan?
The most common side effects of Rizatriptan are:
If you feel very listless, shaky, or dizzy after taking Rizatriptan, it is better not to operate machinery or cars.
Other common side effects are flushing, reddening of the skin (“flush”) or sensory disturbances. The latter are noticeable, for example, as tingling or prickling in the hands and usually pass after a short time. Itching or blisters on the skin can also be an undesirable consequence.
Side effects of the digestive system are often dry mouth, heartburn, nausea and vomiting or diarrhea. Increased thirst may occur. In some cases, rizatriptan causes abdominal pain.
If patients take rizatriptan frequently over a long period of time, they may experience a continuous headache (drug-induced headache).
If you experience additional chest pain or shortness of breath, call an ambulance immediately.
Rarely, patients have a hypersensitive reaction to rizatriptan. If there are signs of a severe allergic reaction such as rash, difficulty swallowing, shortness of breath, and poor circulation, also call a doctor immediately.
For more side effects, see the package leaflet that came with your rizatriptan medicine. Contact your doctor or pharmacist if you suspect any unwanted side effects.
How to get medicines containing rizatriptan
Medicines containing the active ingredient rizatriptan are available by prescription in Germany, Austria, and Switzerland in any dosage and package size and are available only in pharmacies.
Other triptans can be bought in small packs in pharmacies without a prescription (e.g. almotriptan). However, there is no over-the-counter version of rizatriptan.
When is rizatriptan used?
In some patients, rizatriptan relieves not only headaches but also other migraine symptoms such as nausea or sensitivity to light and sound.
How to take rizatriptan
Patients are best advised to take rizatriptan as early as possible, when the first signs of migraine headache appear. The usual dose is 10 milligrams, but preparations containing 5 milligrams are also available. They are intended primarily for patients whose liver or kidneys have limited function.
Patients who have migraines with aura should not take triptans until the aura has subsided.
Rizatriptan is available as a tablet or as a melting tablet, each containing 5 or 10 milligrams. The melting tablets are particularly suitable for patients who have difficulty swallowing or when migraine attacks are accompanied by nausea and vomiting. Patients swallow the tablets whole with a glass of water. Melt tablets, on the other hand, are placed on the tongue and dissolve there.
If a headache occurs again after the first tablet, sufferers can take another one after two hours at the earliest. The maximum dose within 24 hours is two tablets or two melting tablets.
Do not take another dose of rizatriptan if the first one did not help. Alternative pain medications may improve your symptoms. Talk to your doctor or pharmacist about this.
When should you not take rizatriptan?
Medicines containing rizatriptan should not be taken:
- if you are known to be allergic to the active substance or to any of the other ingredients of the medicine
- if you have severe liver or kidney disease
- if you have untreated or uncontrolled high blood pressure
- coronary artery disease (coronary heart disease, possibly with angina pectoris)
- peripheral arterial occlusive disease (PAVD), also known as “smoker’s leg
Simultaneous use of some medications also militates against rizatriptan. These include:
- other triptans (e.g. sumatriptan)
- ergotamines, which are also effective against migraines
- certain medications for depression, called monoamine oxidase inhibitors (MAO inhibitors such as moclobemide or tranylcypromine)
- linezolid, an antibiotic that is also an MAO inhibitor
If you have taken an MAO inhibitor for the last time, wait at least two weeks before using rizatriptan.
Patients who are lactose intolerant are best to be aware of the additional ingredients in rizatriptan tablets: some contain the lactose. They prefer to use Rizatriptan melting tablets, which are lactose-free and therefore better tolerated. In addition, there are also classic tablets without lactose.
What interactions can occur under Rizatriptan?
Patients often receive selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs) for depression. If they then also use rizatriptan, an excess of the neurotransmitter serotonin can develop. You can read about what then happens and how this excess manifests itself in our article “Serotonin syndrome”.
If propranolol (beta blocker) is taken at the same time, the amount of active substance of rizatriptan in the blood may increase. If propranolol is necessary, the doctor will adjust the dose. If you are taking other beta blockers, talk to your doctor.
Dietary supplements or medicines containing St. John’s wort may cause unwanted side effects more often. Therefore, inform your doctor or pharmacist about the use of herbal medicines as well.
Rizatriptan during pregnancy and breastfeeding
Doctors therefore always check whether treatment with triptans is really necessary. If so, they prescribe triptans that have been better studied than rizatriptan (e.g. sumatriptan).
According to animal studies, rizatriptan passes into breast milk in large amounts. However, a single dose of rizatriptan is still possible under a doctor’s instructions. Ideally, mothers should discontinue breastfeeding for 24 hours after ingestion.
