Hypotension diphenhydramine

Campath) hypotension prolonged immunosuppression (resulting in infectious complications) during treatment. Premedicate with acetaminophen, diphenhydramine, with or without a steroid to alleviate infusion-related reactions. Subcutaneous dosing may lessen acute toxicity. Initially 3 mg/day as a 2-hour infusion, increase to 1 0 mg/day, then 30 mg/day as tolerated. 

Geriatric Considerations - Summary Diphenhydramine is a first-generation etha-nolamine antihistamine with potent Hj-receptor antagonism. It also has significant anticholinergric properties and causes somnolence at normal doses. Older adults taking this drug are at risk of dizziness and hypotension and diphenhydramine would... 

Diphenhydramine Competitive antagonism at Hi receptors Reduces or prevents histamine effects on smooth muscle, immune cells also blocks muscarinic and adrenoceptors highly sedative IgE immediate allergies, especially hay fever, urticaria some use as a sedative, antiemetic, and antimotion sickness drug Oral and parenteral t duration 4-6 h Toxicity Sedation when used in hay fever, muscarinic blockade symptoms, orthostatic hypotension Interactions Additive sedation with other sedatives, including alcohol some inhibition of CYP2D6, may prolong action of some 13 blockers... 

Elevations of TCA levels may occur when combined with CYP2D6 inhibitors or from constitutional factors. About 7% of the Caucasian population in the USA has a CYP2D6 polymorphism that is associated with slow metabolism of TCAs and other 2D6 substrates. Combination of a known CYP2D6 inhibitor and a TCA in a patient who is a slow metabolizer may result in additive effects. Such an interaction has been implicated, though rarely, in cases of TCA toxicity. There may also be additive TCA effects such as anticholinergic or antihistamine effects when combined with other agents that share these properties such as benztropine or diphenhydramine. Similarly, antihypertensive drugs may exacerbate the orthostatic hypotension induced by TCAs. 

Infliximab intravenous infusions result in acute adverse infusion reactions in up to 10% of patients, but discontinuation of the infusion for severe reactions is required in less than 2%. Infusion reactions are more common with the second or subsequent infusions than with the first. Early mild reactions include fever, headache, dizziness, urticaria, or mild cardiopulmonary symptoms that include chest pain, dyspnea, or hemodynamic instability. Reactions to subsequent infusions may be reduced with prophylactic administration of acetaminophen, diphenhydramine, or corticosteroids. Severe acute reactions include significant hypotension, shortness of breath, muscle spasms, and chest discomfort such reactions may require treatment with oxygen, epinephrine, and corticosteroids. 

She lost consciousness and developed arterial hypotension. She responded to intravenous diphenhydramine and hydrocortisone. Intradermal skin tests were positive for prednisone and negative for methylprednisolone and hydrocortisone. An oral challenge test with prednisone led to flushing, nausea, dizziness, tachycardia, and hypotension and responded to intravenous diphenhydramine and hydrocortisone. Challenge tests with intravenous methylprednisolone and hydrocortisone were negative. 

Adverse reactions to human serum albumin are uncommon and usually mild, such as itching and urticaria. Serious reactions are rare. A patient who has reacted violently to albumin on one occasion may tolerate it well on another after being given an antihistamine such as diphenhydramine (1). Aggregates present in protein preparations may be the cause of some reactions. Another postulated cause may be the presence of antibodies against genetic variants of human albumin (2). Hypotensive reactions due to the presence of a prekallikrein activator in some batches of formulations can occur. 

Hypotension, bronchospasm, and facial flushing occurred in a 38-year-old man with advanced testicular cancer associated with an intravenous infusion of etoposide (127). The reaction began within 3 minutes after the start of the infusion and resolved with intravenous fluids and diphenhydramine. Later, he was given four doses of etoposide after pretreatment with diphenhydramine and dexamethasone, without incident. 

Pretreatment with Hi and H2 receptor antagonists (diphenhydramine 1 mg/kg and cimetidine 4 mg/kg) intravenously serially over 3 minutes starting 10 minutes before the infusion of vancomycin permitted rapid vancomycin administration (1 g over 10 minutes) in 17 of 19 patients compared with eight of 19 patients treated with placebo in a prospective, randomized, double-blind, placebo-controUed study of patients undergoing elective arthroplasty (22). Hypotension occurred in 2 versus 12 of the patients, and 12 versus 19 of the patients had a rash. Serum histamine concentrations were raised after vancomycin administration in both groups. 

In general, the MoAbs used in treating cancer are relatively well tolerated compared with conventional cytotoxic chemotherapy. The main adverse effect associated with rituximab use is infusion-related or hypersensitivity reactions. Patients may experience fever, rigors, dyspnea, hypotension, and rarely anaphylactoid reactions. Premedication with acetaminophen, diphenhydramine, and corticosteroids can reduce these reactions. Patients with significant tumor burden at the time of first treatment with rituximab may experience tumor lysis syndrome, and appropriate measures should be implemented to prevent this complication in these patients. 

Some antihistaminics, such as promethazine and diphenhydramine, have local anesthetic properties. They may be used substitutively in patients who are allergic to both amide and ester types of local anesthetics. Some phenothiazine antihistaminics, such as promethazine, have alpha-adrenergic blocking effects. Therefore, like phenothiazine neuroleptics, promethazine may cause orthostatic hypotension. 

D. Toxicity and Interactions Sedation is common, especially with diphenhydramine, doxylamine, and promethazine. It is much less common with second-generation agents, which do not enter the CNS readily. Antimuscarinic effects such as dry mouth and blurred vision occur with some first-generation drugs in some patients. Alpha-blocking actions may cause orthostatic hypotension. 

A. Rapid intravenous administration is associated with hypotension, bradycardia, and anaphylactoid reactions. Have epinephrine (see p 442), diphenhydramine (p 436), and cimetidine or another Hj blocker (p 428) ready. Reaction may be prevented by avoiding high infusion rates of > 5 mg/min. 

Lipsius et al. re-evaluated the mechanism of tetrodo-toxin-induced hypotension and reported convincing evidence that the drug dilated skeletal muscle vasculature by a direct action, which was unaltered by either o-or 8-blocking agents or by the antihistamine diphenhydramine. The chemistry33 and pharmacology of tetrodotoxin (VI) have been reviewed. 

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