Rapid exposure to altitudes more than 8,000 feet above sea level can cause serious medical problems. Since the last Medical Letter article on this subject (Vol. 30, page 89, 1988), some new information on prevention and treatment of these disorders has been reported.

Carvedilol (Coreg - SmithKline Beecham and Boehringer-Mannheim), a betaadrenergic and alpha-adrenergic blocker approved by the FDA for treatment of hypertension in 1995, but not marketed at that time, has now been approved and marketed for treatment of mild or moderate (NYHA class II or III) heart failure stabilized on other drugs. It is being promoted as an add-on drug that reduces the morbidity and mortality of the disease.

Bosentan (Tracleer - Actelion), a non-peptide endothelin receptor antagonist, has been approved by the FDA for oral treatment of patients who have pulmonary arterial hypertension (PAH) with symptoms of dyspnea at rest or with minimal exertion.

Treprostinil sodium (tre prost' in il; Remodulin - United Therapeutics), a prostacyclin analogue, has been approved by the FDA for continuous subcutaneous (SC) treatment of patients with pulmonary arterial hypertension who have dyspnea on more than minimal exertion (NYHA Class II-IV).

Several recent case reports suggest that oral sildenafil may be effective for treatment of pulmonary arterial hypertension (PAH). Sildenafil is currently marketed as Viagra for treatment of erectile dysfunction (Medical Letter 1998; 40:51).

The FDA has approved the use of aliskiren (Tekturna), a direct renin inhibitor, with valsartan (Diovan), an angiotensin-receptor blocker (ARB), in a fixed-dose combination as Valturna (Novartis) for treatment of hypertension in patients already taking both drugs or not adequately controlled on monotherapy, and as initial therapy in those likely to need multiple drugs to control their blood pressure.

Meloxicam, a nonsteroidal anti-inflammatory drug (NSAID) with some cyclooxygenase-2 (COX-2) selectivity in vitro, has been approved by the FDA for treatment of osteoarthritis.

The FDA has approved use of tadalafil (Adcirca - Lilly/United Therapeutics) for treatment of pulmonary arterial hypertension (PAH).

The FDA has approved the sGC stimulator riociguat (rye" oh sig' ue at; Adempas – Bayer) for oral treatment of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) following surgery or when surgery is not an option. It is the first drug to be approved for treatment of CTEPH.

Aliskiren (Tekturna - Novartis), the first direct renin inhibitor for treatment of hypertension, has been approved for use in a fixed-dose combination with the diuretic hydrochlorothiazide (Tekturna HCT - Novartis). Many angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) are also available in fixed-dose combinations with hydrochlorothiazide (HCTZ).