Octreotide is an analogue of somatostatin. Like endogenous somatostatin, it exerts a potent inhibitory effect on the release of anterior pituitary growth hormone and thyroid-stimulating hormone, and peptides of the gastroenteropancreatic endocrine system, while overcoming some of the shortcomings of exogenously administered somatostatin, namely a short duration of action, a need for intravenous administration and postinfusion rebound hypersecretion of hormone. Clinical studies have shown that octreotide is effective in the treatment of acromegaly and thyrotrophinomas. In comparative trials octreotide was significantly superior to bromocriptine in patients with acromegaly. Octreotide also appears to provide a significant advantage over existing therapies in the management of the carcinoid syndrome and offers considerable therapeutic potential in reversing carcinoid crises which may be life-threatening. Trials in patients with tumours producing vasoactive intestinal peptide demonstrated that octreotide may be an effective first-line choice for this condition, which has usually metastasised and become refractory to traditional symptomatic therapy. In limited studies in patients with high-output secretory diarrhoea, including cryptosporidium-related diarrhoea associated with AIDS and in patients with small bowel fistulas, octreotide has been shown to be effective in reducing stool/fistula output. However, well-designed clinical trials are still required to confirm its long term usefulness in these disorders. Similarly, although the use of octreotide in other conditions such as neonatal hypoglycaemia caused by nesidioblastosis, reactive pancreatitis, insulin-dependent diabetes mellitus, postprandial hypotension and the dumping syndrome has provided encouraging preliminary results, more studies are needed to clarify the place of octreotide in their treatment. Overall, octreotide appears to be well tolerated with the most frequently reported reactions being pain at the site of injection and gastrointestinal symptoms such as abdominal cramps, nausea, bloating, flatulence, diarrhoea and steatorrhoea. These adverse effects usually abate with time. Additionally, octreotide, like endogenous somatostatin, may also result in cholelithiasis, presumably by altering fat absorption and possibly by decreasing motility of the gallbladder. Thus, octreotide represents a new departure from traditional therapies in the treatment of various pathophysiological states associated with excessive peptide production and secretion. It offers a significant advantage over existing therapies in the medical management of patients with acromegaly, thyrotrophinomas, the carcinoid syndrome, tumours producing vasoactive intestinal peptide and severe secretory diarrhoea in whom conventional management options have either become exhausted or have provided suboptimal symptomatic relief.

Metipranolol is a non-selective beta-adrenoceptor blocking agent used for the topical treatment of elevated intraocular pressure in patients with chronic open angle glaucoma or ocular hypertension. In double-blind comparative studies of up to 4 months duration, metipranolol 0.1 to 0.6% produced comparable reductions in intraocular pressure to timolol 0.25 to 0.5% and levobunolol 0.5%, lowering pressure by about 20 to 29% from baseline. Metipranolol has been well tolerated by most patients, producing only minor changes in objective measurements of ophthalmic status and systemic parameters. Similarly, subjective ophthalmic complaints have been minimal although reports of initial stinging or burning upon instillation have occurred. Further published reports, in which larger numbers of patients are treated over extended periods, are needed to confirm the drug's apparent long term comparative efficacy. Studies of ocular metipranolol to date are encouraging, and the drug demonstrates a lasting intraocular pressure reducing effect with good tolerability. Thus, ocular metipranolol provides a viable alternative to ocular timolol and levobunolol in the topical treatment of chronic open angle glaucoma or ocular hypertension.

Streptokinase has been administered to many thousands of elderly patients with acute myocardial infarction. Results of large, randomised trials provide convincing evidence that intravenous streptokinase confers a distinct survival benefit in this population subgroup following myocardial infarction. The placebo-controlled ISIS-2 study demonstrated a 5-week absolute mortality reduction of 38 per 1000 patients aged 60 to 69 years administered streptokinase, compared with only 16 per 1000 for patients aged less than 60 years. Combining streptokinase with aspirin further reduces mortality, as shown by a 5-week absolute mortality reduction of 70 per 1000 patients aged 60 to 69 years administered this regimen in the ISIS-2 trial. While ideally patients should receive streptokinase as soon as possible after symptom onset, late benefit has been observed in patients presenting up to 12 hours after pain onset, as is often the case with the elderly. Indeed, in patients treated > 6 hours after infarct in the GUSTO trial, streptokinase produced lower mortality results than accelerated recombinant tissue plasminogen activator (rt-PA). However, in contrast to the similar effects of streptokinase and conventionally administered rt-PA on overall survival demonstrated in previous large trials, the GUSTO study showed a lower mortality rate for accelerated rt-PA than for streptokinase in the elderly and in the total patient population. The most frequent adverse effects associated with streptokinase therapy are haemorrhagic complications, with an incidence of 0.4% for major bleeding (requiring transfusion) and 3.6% for minor bleeding among the total population in the GISSI-1 and ISIS-2 trials. An excess of stroke, particularly haemorrhagic stroke, occurring with rt-PA in GUSTO and other major mortality trials affirms the use of streptokinase as a suitable option in the elderly who are at increased risk of this complication. Significantly reduced values of end-systolic volume and regional wall motion index have been observed in elderly patients following streptokinase therapy. Overall, streptokinase and rt-PA seem to cause similar improvements in left ventricular function in this age group. Patency of occluded coronary arteries appears to be achieved in a high percentage of elderly patients following streptokinase therapy, based on a small sample. Thus, in view of the extensive clinical experience that now exists, intravenous streptokinase represents an appropriate alternative in elderly patients with acute myocardial infarction, and may be considered a first-line therapy in selected individuals, such as those with multiple risk factors for stroke or who present later than 6 hours after infarct.(ABSTRACT TRUNCATED AT 400 WORDS)