Anti-Itch (diphenhydramine HCl)

Dosage should be individualized according to the patient's response and tolerance.

Diphenhydramine hydrochloride usually is administered orally.

Diphenhydramine citrate usually is administered orally.

When oral therapy is not feasible, diphenhydramine hydrochloride may be given by deep IM or, preferably, IV injection. The drug should not be given subcutaneously, intradermally, or perivascularly because of its irritating effects; local necrosis has been reported following subcutaneous or intradermal administration of parenteral diphenhydramine. IV use of the drug in a home-care setting should be employed under careful supervision. Use of diphenhydramine for local anesthesia via local infiltration is discouraged because of the risk of local tissue necrosis. Diphenhydramine hydrochloride should not be given to premature or full-term neonates. (See Cautions: Pediatric Precautions.)

For the temporary relief of pruritus associated with various skin conditions and disorders, diphenhydramine hydrochloride-containing preparations are applied topically in the form of a cream, lotion, or topical solution. The possibility of clinically important percutaneous absorption of the drug following topical application should be considered. (See Cautions.)

There is no enhanced messaging for this drug.

There are no contraindication interactions for this drug.

Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

Local Anesthetics/Long-Acting Bupivacaine

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Concurrent use of other local anesthetics or use of other local anesthetics within 96 hours following long-acting bupivacaine may result in additive neurologic and cardiovascular effects. Use of articaine, benzocaine, bupivacaine, lidocaine, mepivacaine, prilocaine, procaine, ropivacaine, and tetracaine may also increase the risk of methemoglobinemia.(1,2) Non-liposomal bupivacaine may impact the pharmacokinetic and/or physicochemical properties of the liposomal formulation when administered in the same syringe or used simultaneously unless the ratio of mg of non-liposomal bupivacaine to mg of bupivacaine liposomal does not exceed 1:2.(1) Local anesthetics other than bupivacaine may trigger the immediate release of bupivacaine from the liposomal formulation when administered together locally.(1)

CLINICAL EFFECTS: Concurrent or use of local anesthetics with 96 hours of use of long-acting bupivacaine may result in neurologic and cardiovascular toxicity. Use of articaine, benzocaine, bupivacaine, lidocaine, mepivacaine, prilocaine, procaine, ropivacaine, and tetracaine may also result in methemoglobinemia.(1,2) Non-liposomal bupivacaine may impact the pharmacokinetic and/or physicochemical properties of the liposomal formulation when administered in the same syringe or used simultaneously unless the ratio of mg of non-liposomal bupivacaine to mg of bupivacaine liposomal does not exceed 1:2.(1) Local anesthetics other than bupivacaine may trigger the immediate release of bupivacaine from the liposomal formulation when administered together locally.(1)

PREDISPOSING FACTORS: Use of additional agents that are associated with methemoglobinemia may further increase the risk of methemoglobinemia.(1) Patients who are at increased risk of developing methemoglobinemia include those with glucose-6-phosphate dehydrogenase deficiency, congenital or idiopathic methemoglobinemia, cardiac or pulmonary compromise, infants under 6 months of age, and concurrent exposure to oxidizing agents or their metabolites are more susceptible to developing clinical manifestations of the condition. If local anesthetics must be used in these patients, close monitoring for symptoms and signs of methemoglobinemia is recommended.(1)

PATIENT MANAGEMENT: Avoid the use of other local anesthetics within 96 hours following the administration of long-acting bupivacaine. In patients for whom use is required, monitor for neurologic and cardiovascular effects. Also monitor for methemoglobinemia with use of articaine, benzocaine, bupivacaine, lidocaine, mepivacaine, prilocaine, procaine, ropivacaine, and tetracaine.(1,2) Non-liposomal bupivacaine may be administered in the same syringe as bupivacaine liposomal or injected immediately before bupivacaine liposomal as long as the ratio of mg of non-liposomal bupivacaine to mg of bupivacaine liposomal does not exceed 1:2.(1) Lidocaine may be administered 20 minutes or more prior to bupivacaine. It is unknown if other local anesthetics may be used without compromising the release characteristic of bupivacaine liposomal.(1)

DISCUSSION: Concurrent use of other local anesthetics or use of other local anesthetics within 96 hours following long-acting bupivacaine may result in additive neurologic and cardiovascular effects. Use of articaine, benzocaine, bupivacaine, lidocaine, mepivacaine, prilocaine, procaine, ropivacaine, and tetracaine may also increase the risk of methemoglobinemia.(1,2) Non-liposome bupivacaine may impact the pharmacokinetic and/or physicochemical properties of the liposomal formulation when administered in the same syringe or used simultaneously unless the ratio of mg of non-liposomal bupivacaine to mg of bupivacaine liposomal does not exceed 1:2.(1) Local anesthetics other than bupivacaine may trigger the immediate release of bupivacaine from the liposomal formulation when administered together locally. Lidocaine may be administered 20 minutes or more prior to bupivacaine. It is unknown if other local anesthetics may be used without compromising the release characteristic of bupivacaine liposomal.(1)

There are no moderate interactions for this drug.

There is no enhanced messaging for this drug.

There are no contraindication contraindications for this drug.

• Bacterial skin and skin structure infection
• Burns
• Large open wound

• Hypothalamic-pituitary insufficiency
• No disease contraindications

There is no enhanced messaging for this drug.

Less Frequent

• Dermatitis due to topical drug
• Folliculitis
• Purpura
• Skin and skin structure infection
• Skin atrophy

Rare or Very Rare

• Acute respiratory failure
• Adrenocortical insufficiency
• Anaphylaxis
• Angioedema
• Bradycardia
• Bronchospastic pulmonary disease
• Bullous dermatitis
• Burns
• Cardiac arrhythmia
• Cataracts
• Central serous chorioretinopathy
• CNS toxicity
• Cyanosis
• Eyelid edema
• Glaucoma
• Growth failure
• Headache disorder
• Hypotension
• Hypothalamic-pituitary insufficiency
• Intracranial hypertension
• Methemoglobinemia
• Ocular hypertension
• Respiratory depression
• Seizure disorder
• Skin hypopigmentation
• Skin striae
• Skin ulcer
• Unconsciousness
• Urticaria

More Frequent

• Erythema
• Stinging of skin

Less Frequent

• Acute pain at drug application site
• Blanching of skin
• Blurred vision
• Edema
• Erythema
• Headache disorder
• Paresthesia
• Pruritus of skin
• Pruritus of skin
• Skin rash
• Skin rash
• Stinging of skin
• Stinging of skin
• Telangiectasia
• Treatment site sequelae
• Urticaria

Rare or Very Rare

• Acneiform eruption
• Acute cognitive impairment
• Alopecia
• Apprehension
• Blistering skin
• Blurred vision
• Contact dermatitis
• Contact dermatitis
• Dizziness
• Drowsy
• Dry skin
• Dyschromia
• Euphoria
• Glycosuria
• Hirsutism
• Hypercortisolism
• Hyperesthesia
• Hyperglycemia
• Miliaria
• Muscle fasciculation
• Nervousness
• Perioral dermatitis
• Sensation of cold
• Sensation of warmth
• Skin irritation
• Tinnitus
• Tremor
• Vomiting

No enhanced messaging available.

No enhanced messaging available.

Reproduction studies in rats and rabbits receiving diphenhydramine hydrochloride dosages up to 5 times the recommended human dosage have not revealed evidence of harm to the fetus. However, diphenhydramine has been shown to cross the placenta. In one epidemiologic study, use of bromodiphenhydramine (no longer commercially available) but not diphenhydramine was associated with an increased risk of teratogenic effects. In another epidemiologic study, there also was no evidence of increased risk of teratogenicity associated with diphenhydramine use during the first trimester, although a modest association could not be ruled out. Use of diphenhydramine during the first trimester of pregnancy has been associated with an increased risk of cleft palate alone or combined with other fetal abnormalities, and the drug has been reported to potentiate the teratogenic effect of morphine in mice. The manufacturers state that there are no adequate and controlled studies to date using diphenhydramine in pregnant women, and the drugs should be used during pregnancy only when clearly needed.

Diphenhydramine has been detected in milk. Because of the potential for serious adverse reactions to antihistamines in nursing infants, a decision should be made whether to discontinue nursing or diphenhydramine, taking into account the importance of the drug to the woman.

No enhanced messaging available.