Ocular autonomic drugs

Shaffer RN. Problems in the use of autonomic drugs in ophthalmology. In Leopold IH, ed. Ocular therapy complications and management. St. Louis CV Mosby, 1967 2 18-23. 

This is caused by excessive stimulation of CNS and peripheral serotonin receptors and is characterized by changes in mental state, autonomic hyperactivity (hypertension, tachycardia, hyperthermia, may be up to 4l°C, hyperactive bowel sounds, mydriasis, excessive sweating) and neuromuscular abnormality (tremor, clonus, ocular clonus, hypertonicity, hyperreflexia) the latter may lead to rhabdomyolysis with consequent risk of renal failure, hyperkalaemia and hypocalcaemia. Symptoms usually occur within 6 hours of taking the provoking drug, Tremor, akathisia and diarrhoea are early features. 

Practitioners should be aware of over-the-counter (OTC) medications and folk or home remedies that patients may be using. Many patients may not consider OTC agents, especially antihistamines and decongestants for hay fever and colds, as drugs. These can affect the autonomic nervous system. OTC preparations can potentially interact with ocular drugs, such as homatropine and phenylephrine, that also influence autonomic functions. 

Drugs affecting the autonomic nervous system or central vestibular system or causing extrapyramidal effects have been associated with ocular manifestations such as nystagmus, diplopia, extraocular muscle palsy, and oculogyric crisis. Table 35-8 fists drugs that can affect extraocular muscles. 

---