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warnings
WARNINGS Sympathomimetic amines should be used judiously and sparingly in patients with hypertension, diabetes meltitus, ischemic heart disease, increased intraocular pressure, hyperthyroidism or prostatic hypertrophy. Sympathomimetics may produce central nervous system stimulation with convulsions or cardiovascular collapse with accompanying hypotension. Do not exceed recommended dosage. Hypersensitive crises can occur with concurrent use of phenylephrine and MAO inhibitors (and for 14 days after stopping MAOI therapy), indomethacin, or with beta-blockers and methyldopa. If a hypertensive crisis occurs, these drugs should be discontinued immediately and therapy to lower blood pressure should be instituted: Fever should be managed by means of external cooling. Before prescribing medication to suppress or modify a cough, it is important that the underlying cause of the cough is identified, that modification of the cough does not increase the risk of clinical or physiological complications, and that appropriate therapy for the primary disease is instituted.
ADVERSE REACTIONS Hyperreactive individuals may display ephedrine-like reactions such as tachycardia, palpitations, headache, dizziness, or nausea. Sympathomimetic amines have been associated with certain untoward reactions including fear, anxiety, nervousness, restlessness, tremor, weakness, pallor, respiratory difficulty, dysuria, insomnia, hallucinations, convulsions, CNS depression, arrhythmias, and cardiovascular collapse with hypotension. No serious side effects from guaifenesin have been reported.