18.104.22.168 Dopamine receptor agonists
|1st choice||Ropinirole tablets 250 micrograms, 500 micrograms,1mg, 2mg, 5mg;||Dose:|
Immediate release tablets:
Initial dose is 750microgram daily in 3 divided doses, increased by increments of 750 micrograms daily at weekly intervals to 3mg daily in 3 divided doses; further increased by increments of 1.5mg- 3mg daily at weekly intervals according to response; usual range 9-16mg daily in 3 divided doses. Higher doses (max 24mg) are often necessary under specialist advice.
Ropinirole tablets m/r 2mg, 4mg, 8mg
|Modified release tablets: stable patients transferring from ropinirole immediate release tablets, initially ropinirole m/r once daily substituted for total daily dose of equivalent immediate-release tablet|
|Pramipexole tablets 88 micrograms base (125 micrograms salt), 180micrograms base (250 micrograms salt), 350micrograms base (500micrograms salt), 700micrograms base (1mg salt); pramipexole tablets m/r 260micrograms, 520 micrograms, 1.05mg, 1.57mg, 2.1mg, 2.62mg, 3.15mg (See BNF for equivalent strengths in terms of pramipexole dihydrochloride monohydrate salt)||Dose:|
Immediate release tablets:
initial dose 88micrograms three times daily, dose doubled every 5-7 days if tolerated, to 350 micrograms three times daily; further increased if necessary by 180micrograms three times daily at weekly intervals; max 3.3mg daily in 3 divided doses
Modified release tablets: initially 260micrograms once daily, dose doubled every 5-7 days to 1.05mg once daily; further increased if necessary by 520micrograms daily at weekly intervals; max 3.15mg once daily
- Ropinirole or pramipexole can be used as monotherapy or adjunctive therapy with levodopa.
- Ergot derivatives (bromocriptine, cabergoline and pergolide) have rarely been associated with pulmonary, retroperitoneal, pericardial and valvular fibrotic reactions and require regular clinical monitoring (see BNF). They are no longer recommended as first line treatment (see Drug Safety Update – Ergot-derived dopamine agonists: risk of fibrotic reactions for further information).
- Dopamine receptor agonists are emetogenic. Nausea will often settle over time as tolerance occurs. If nausea is persistent or severe:
- Do not use metoclopramide or prochlorperazine.
- Domperidone can be prescribed, reducing or stopping it when the nausea or vomiting settles. Domperidone is associated with a small increased risk of serious cardiac side effects. Its use is now restricted to the relief of symptoms of nausea and vomiting and the dosage and duration of use have been reduced. Domperidone is now contraindicated in those with underlying cardiac conditions and other risk factors (click here for more information). See also section 4.6.1.
- When used as adjunctive therapy, dopamine receptor agonists can exacerbate levodopa-induced adverse effects.
- All dopamine receptor agonists can cause postural hypotension and neuropsychiatric adverse effects.
- Apomorphine is a powerful dopamine receptor agonist that must be given subcutaneously, either by infusion or on an “as required” basis. It is approved for use under a shared care protocol.
- Amantadine improves mild bradykinetic disabilities, tremor and rigidity. It may also be useful in dyskinesias in more advanced disease.
- Rotigotine patches may be useful in patients with complicated oral regimes before adding dopamine receptor agonists and in those with delayed gastric emptying or swallow problems.