Posted by ed_uk on November 5, 2005, at 9:50:24
In reply to Sublingual Nifedipine?, posted by tecknohed on November 4, 2005, at 14:48:42
Hi Kev
Nifedipine is not well absorbed sublingually, it is more active when it's swallowed. There are no approved nifedipine preparations for sublingual use in the UK, although immediate release nifedipine capsules have been administered in this way.
In the treatment of an MAOI/tyramine-induced hypertensive crisis, nifedipine is given as an oral capsule. The capsule should be swallowed (not held under the tongue) - you can bite the capsule first if you want to.
Nifedipine is available both as slow release capsules/tablets and as standard/immediate release capsules. The immediate release capsules have been used to treat MAOI-induced hypertensive crises. In the UK, these capsules are available as a generic. They are also available as Adalat capsules (not Adalat tablets - which are 'slow release').
In the US, immediate release nifedipine capsules are available under the brand name Procardia capsules (not Procardia XL tablets - which are slow release).
Adalat (UK) capsules are available as 5mg and 10mg capsules. Procardia (US) capsules are available as 10mg and 20mg capsules.
Nifedipine is an inappropriate treatment for most forms of hypertensive crisis eg. due to kidney disease. It's safety is uncertain and it can cause significant side effects. The rapid BP drop induced by nifedipine is dangerous for many hypertensive patients with chronic hypertension, a more gradual reducation in BP is desirable. Nevertheless, an MAOI-induced hypertensive crisis is characterised by a very rapid BP rise in a previously normotensive patient. Under these cirumstances, it is possible that nifedipine might be an acceptable treatment. Ideally, an MAOI hypertensive crisis should always be treated in hospital. Phentolamine (if available) can be given intravenously. Many emergency departments may not stock phentolamine. Sodium nitroprusside IV infusion could be used as an alternative.
There is no ideal drug for the treatment of MAOI-induced hypertensive crisis. Nifedipine (5 or 10mg) may be suitable as a pre-hospital treatment but this is controversial. Chlorpromazine (Largactil, Thorazine) has been used in a similar manner.
A hypertensive crisis can cause considerable pain and anxiety, which might theoretically aggravate the hypertension. Diazepam (Valium) 10mg can be given for anxiety. Paracetamol 1000mg can be given for pain.
Kind regards
Ed
poster:ed_uk
thread:575395
URL: http://www.dr-bob.org/babble/20051031/msgs/575607.html