Healthcare providers are often asked if drugs can be used past their expiration date. Because of legal restrictions and liability concerns, manufacturers do not sanction such use and usually do not comment on the safety or effectiveness of their products beyond the date on the label. Since our last article on this subject, more data have become available.

Healthcare providers are often asked if drugs can be used past their expiration date. Because of legal restrictions and liability concerns, manufacturers do not sanction such use and usually do not even comment on the safety or effectiveness of their products beyond the date on the label. Since our last publication on this subject, more data have become available.

Drugs for glaucoma, age-related macular degeneration, bacterial conjunctivitis, and dry eyes are reviewed here. Ophthalmic drugs can have local and systemic adverse effects. In addition, for some elderly patients, the complexity of self-administering numerous ophthalmic drugs may be the limiting factor in their ability to care for themselves. Drugs for the treatment of allergic conjunctivitis will be reviewed in a future issue of Treatment Guidelines on Drugs for Allergic Disorders.

Healthcare providers are often asked if patients can use drugs after their expiration date. Pharmaceutical companies, because of legal restrictions and liability concerns, will not sanction such use and might not even comment on the safety or effectiveness of using their products beyond the date on the label. Since the last Medical Letter publication on this subject, more data have become available.

Irritable bowel syndrome (IBS) is a common disorder, occuring in about 15% of the US population; it is 2-3 times more frequent in women than in men. IBS is characterized by chronic abdominal pain or discomfort and altered bowel habits.

Many drugs can cause psychiatric symptoms, but a causal connection is often difficult to establish. Psychiatric symptoms that emerge during drug treatment may also be due to the underlying illness, previously unrecognized psychopathology, or psychosocial factors. The withdrawal of some drugs can cause symptoms such as anxiety, psychosis, delirium, agitation or depression.

The recent terrorist attacks on the US have led to many questions about the clinical effects, prevention and treatment of injury caused by chemical warfare agents.

The recent attack in the Tokyo subway has led to many questions about the clinical effects, treatment and prevention of nerve gas poisoning.

Cardiac arrest may be due to tachyarrhythmias, bradyarrhythmias, or asystole. Without treatment, permanent damage to the cerebral cortex usually begins within five minutes and is complete in ten. After cardiopulmonary resuscitation (CPR) has been started and electrical defibrillation, when indicated, has been applied, drugs may help promote recovery.

With the possibility that chemical weapons may be used against United States armed forces in the Persian Gulf, the military has taken steps to protect our troops against poison gas, particularly ''nerve agents';'; (MA Dunn and FR Sidell, JAMA, 262:649, 1989).