Cortical blindness after nifedipine treatment

The Prescriber's Guide to the MAOI Diet-Thinking Through Tyramine Troubles

This review article features comprehensive discussions on the dietary restrictions issued to patients taking a classic monoamine oxidase inhibitor (phenelzine, tranylcypromine, isocarboxazid), or high-dose (oral or transdermal) selegiline. It equips doctors with the knowledge to explain to their patients which dietary precautions are necessary, and why that is so: MAOIs alter the capacity to metabolize certain monoamines, like tyramine, which causes dose-related blood pressure elevations. Modern food production and hygiene standards have resulted in large reductions of tyramine concentrations in most foodstuffs and beverages, including many cheeses. Thus, the risk of consequential blood pressure increases is considerably reduced-but some caution remains warranted. The effects of other relevant biogenic amines (histamine, dopamine), and of the amino acids L-dopa and L-tryptophan are also discussed. The tables of tyramine data usually presented in MAOI diet guides are by nature unhelpful and imprecise, because tyramine levels vary widely within foods of the same category. For this reason, it is vital that doctors understand the general principles outlined in this guide; that way, they can tailor their instructions and advice to the individual, to his/her lifestyle and situation. This is important because the pressor response is characterized by significant interpatient variability. When all factors are weighed and balanced, the conclusion is that the MAOI diet is not all that difficult. Minimizing the intake of the small number of risky foods is all that is required. Many patients may hardly need to change their diet at all.

Oral short-acting antihypertensive medications and the occurrence of stroke: a nationwide case-crossover study

The purpose of the study was to clarify whether short-acting antihypertensives are associated with the occurrence of ischemic stroke and intracerebral hemorrhage (ICH). This was a retrospective case-crossover study using the Taiwan National Health Insurance Research Database. We identified all adult patients hospitalized with a primary diagnosis of ischemic stroke or ICH between January 2005 and December 2013. For each case, short-term and long-term exposure to short-acting antihypertensives, including nifedipine, labetalol and captopril, during the case vs. control periods were compared, and odd ratios (ORs) and 95% confidence intervals (CIs) for ischemic stroke or ICH were calculated with adjustment for confounders. Among 272785 ischemic stroke and 77798 ICH patients, the mean age was 77.8 ± 14.3 years and 70.8 ± 16.6 years, respectively. The short-term use of the three short-acting antihypertensives were all associated with an increase in the incidence of ischemic stroke (nifedipine: OR 4.51, 95% CIs 3.99-5.11; labetalol: OR 2.07; 95% CIs 1.71-2.51; captopril: OR 1.98, 95% CIs 1.72-2.29) and ICH (nifedipine: OR 2.98, 95% CIs 2.30-3.84; labetalol: OR 2.37; 95% CIs 1.66-3.39; captopril: OR 2.48; 95% CIs 1.69-3.63). The long-term use of short-acting nifedipine for 30 days was associated with a modest increase in the risk for ischemic stroke (OR 1.86; 95% CIs 1.42-2.45). Overall, the short-term use of short-acting antihypertensives is associated with a modest increase in the incidence of stroke, and short-acting nifedipine is linked to a substantial rise in the incidence of ischemic stroke. The long-term use of short-acting nifedipine was also related to an increased incidence of ischemic stroke. Physicians should be cautious of prescribing these short-acting antihypertensives.

A reassessment of the safety profile of monoamine oxidase inhibitors: elucidating tired old tyramine myths

This review appraises over 150 recent original papers reporting data that demonstrate the greatly reduced tyramine content of modern-day 'foods', about which the medical literature has a paucity of information. It discusses the cardiovascular pharmacology of tyramine and the characteristics, extent, risks, and treatment of the blood pressure increases that sometimes result from tyramine ingestion (the pressor response). In past decades, cheese was the only food associated with documented fatalities resulting from hypertension. Today, few foods contain problematically high tyramine levels, which is a result of changes in international food production techniques (especially the use of starter cultures), and hygiene regulations. Nowadays, even 'matured' cheeses are usually safe in healthy-sized portions. The mechanism by which tyramine may be produced in foods (by certain micro-organisms) is explained and hundreds of recent estimations of cheeses are reviewed. Numerous other previously inadequately documented foods are reviewed, including fish and soy sauces, salami-type sausages, dried meats, beers, wines, and various condiments. Evidence that the risk of harm from the pressor response has previously been overstated is reviewed, and the iatrogenic harms from hasty and aggressive treatment of hypertensive urgency are re-evaluated. Evidence now suggests that MAOIs are of comparable safety to many newer drugs and are straightforward to use. Previously held concerns about MAOIs are misplaced and some are of over-estimated consequence. The variability of pressor sensitivity to tyramine between individuals means that the knowledge and judgement of doctors, and some care, are still required.