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. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
Rash, Difficulty in sleeping (insomnia, Drowsiness, Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain, Weight gain, Dizziness, Leg cramps, Excessive fluid retention in the body tissues, resulting in swelling (oedema), Spasm of the arteries.
Methysergide (the active ingredient in Deseril) belongs to a group of medicines called the ergot alkaloids. It is used in the prevention of migranes. Although the cause of migraine attacks is not fully understood, it is thought that the widening of blood vessels in the brain causes the pain associated with migraine attacks.
It is also believed that a chemical called serotonin is released in the brain at the beginning of an attack. Serotonin triggers the release of other chemicals which cause blood vessels in the brain to widen. Serotonin itself causes blood vessels in the brain to narrow.
Methysergide blocks serotonin (or 5HT) receptors in the brain. Blocking these receptors stops blood vessels in the brain from dilating and contracting. By stopping these changes methysergide prevents migraines from occuring.
Methysergide has severe side effects and is only used if other treatment options have failed, or the headaches are so severe or regular that this level of treatment is warranted.