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Drug Interactions between atropine / phenobarbital and lenacapavir

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Major

PHENobarbital lenacapavir

Applies to: atropine / phenobarbital and lenacapavir

GENERALLY AVOID: Coadministration with drugs that are combined P-glycoprotein (P-gp) and moderate inducers of CYP450 3A4 or sole moderate inducers of CYP450 3A4 may decrease the plasma concentrations of lenacapavir and result in a potential loss of virologic response. The proposed mechanism is increased clearance due to induction of the isoenzyme CYP450 3A4, which is partly responsible for the metabolism of lenacapavir and induction of the P-gp transporter of which lenacapavir is a substrate. In pharmacokinetic studies conducted in fasted subjects without HIV, coadministration of a single oral dose of lenacapavir 300 mg with the combined P-gp and moderate inducer of CYP450 3A4 efavirenz 600 mg once daily decreased the systemic exposure (AUC) and peak plasma concentration (Cmax) of lenacapavir by approximately 56% and 36%, respectively.

MANAGEMENT: Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiviral drug levels, concomitant use of lenacapavir with drugs that are combined P-gp and moderate inducers of CYP450 3A4 or sole moderate inducers of CYP450 3A4 should generally be avoided.

References (2)
  1. (2022) "Product Information. Sunlenca (lenacapavir)." Gilead Sciences
  2. (2023) "Product Information. Sunlenca (lenacapavir)." Gilead Sciences Pty Ltd, SUNLENCA Product Inf

Drug and food interactions

Major

PHENobarbital food

Applies to: atropine / phenobarbital

GENERALLY AVOID: Concurrent acute use of barbiturates and ethanol may result in additive CNS effects, including impaired coordination, sedation, and death. Tolerance of these agents may occur with chronic use. The mechanism is related to inhibition of microsomal enzymes acutely and induction of hepatic microsomal enzymes chronically.

MANAGEMENT: The combination of ethanol and barbiturates should be avoided.

References (5)
  1. Gupta RC, Kofoed J (1966) "Toxological statistics for barbiturates, other sedatives, and tranquilizers in Ontario: a 10-year survey." Can Med Assoc J, 94, p. 863-5
  2. Misra PS, Lefevre A, Ishii H, Rubin E, Lieber CS (1971) "Increase of ethanol, meprobamate and pentobarbital metabolism after chronic ethanol administration in man and in rats." Am J Med, 51, p. 346-51
  3. Saario I, Linnoila M (1976) "Effect of subacute treatment with hypnotics, alone or in combination with alcohol, on psychomotor skills related to driving." Acta Pharmacol Toxicol (Copenh), 38, p. 382-92
  4. Stead AH, Moffat AC (1983) "Quantification of the interaction between barbiturates and alcohol and interpretation of fatal blood concentrations." Hum Toxicol, 2, p. 5-14
  5. Seixas FA (1979) "Drug/alcohol interactions: avert potential dangers." Geriatrics, 34, p. 89-102
Moderate

atropine food

Applies to: atropine / phenobarbital

GENERALLY AVOID: Use of anticholinergic agents with alcohol may result in sufficient impairment of attention so as to render driving and operating machinery more hazardous. In addition, the potential for abuse may be increased with the combination. The mechanism of interaction is not established but may involve additive depressant effects on the central nervous system. No effect of oral propantheline or atropine on blood alcohol levels was observed in healthy volunteers when administered before ingestion of a standard ethanol load. However, one study found impairment of attention in subjects given atropine 0.5 mg or glycopyrrolate 1 mg in combination with alcohol.

MANAGEMENT: Alcohol should generally be avoided during therapy with anticholinergic agents. Patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them.

References (1)
  1. Linnoila M (1973) "Drug effects on psychomotor skills related to driving: interaction of atropine, glycopyrrhonium and alcohol." Eur J Clin Pharmacol, 6, p. 107-12

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

See also

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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