Drugs acting on arteries

In general, the use of vasodilator therapy is more effective in primary rather than secondary Raynaud's phenomenon (1). Several classes of drug are used to reduce vasospasm in Raynaud's disease. Therapeutic options include:

• calcium antagonists:
  • nifedipine is the drug of choice, reducing the severity and frequency of attacks
    • the only calcium-channel blocker to have a licence for this purpose
    • an initial dosage of 10mg once daily is suggested and this is increased to 10mg twice daily after a week and thereafter increased gradually to 20mg twice daily. The maximum dosage (if tolerated) is 20mg three times daily (2)
  • nicardipine, felodipine, israpidine and amlodipine are also effective (1). These calcium-channel blockers tend to be better tolerated and cause less vasodilatory side-effects; none, however, have a licence for use in Raynaud’s
• naftidrofuryl oxalate - this may produce symptomatic improvement
  • generally very well tolerated, thus is often a good first-line treatment. The initial dose is 100mg three times daily, increased to 200mg three times daily if required (2)

Alternative therapies that have been used in this condition include:

• nitrates:
  • oral glyceryl trinitrate is ineffective, but a topical 2% ointment can be useful when the condition affects precise anatomical sites
    
    
• ACE inhibitors:
  • have been used for severe, disabling attacks, but there is no evidence for their efficacy
    
    
• alpha-adrenoceptor antagonists:
  • thymoxamine has been used for simple, short attacks
  • prazosin is an alternative
  • not established as being effective (3)
    
    
• inositol nicotinate - see BNF
  
  
• selective serotonin reuptake inhibitors - these may be value as vasodilator therapy in Raynaud's phenomenon (1)

Reference:

1. Block JA, Sequeria W (2001). Raynaud's Phenomenon, Lancet; 357 (9273): 2042-8.
2. Prescriber (2005); 16(8).
3. Black CM (1994). Scleroderma (systemic sclerosis). Medicine International; 22(2):70-5.
4. BNF 2.6.4