Is there a contraindication between marijuana use and the anti-rabies vaccination (Human Diploid Cell Vaccine (HDCV) or Purified Chick Embryo Cell Vaccine (PCECV)) regimen?

Marijuana and Anti-Rabies Vaccine: No Contraindication

There is no contraindication between marijuana use and rabies vaccination. The available evidence from ACIP guidelines and rabies vaccine protocols does not identify marijuana as interfering with rabies vaccine efficacy or safety 1.

Evidence Review

Known Drug Interactions with Rabies Vaccine

The only documented drug interaction that affects rabies vaccine immunogenicity involves antimalarial medications:

• Chloroquine phosphate decreases antibody response when administered concurrently with intradermal HDCV 1
• Antimalarials structurally related to chloroquine (e.g., mefloquine) should be avoided with intradermal rabies vaccination, though their interference has not been definitively proven 1
• When antimalarials are necessary, intramuscular administration of rabies vaccine (rather than intradermal) provides adequate protection 1

Immunosuppressive Agents

The guidelines specifically address immunosuppressive medications:

• Corticosteroids and other immunosuppressive agents substantially reduce immune responses to rabies vaccines 2
• Immunosuppressive medications should not be administered during rabies post-exposure prophylaxis unless essential for treatment of other conditions 2
• Immunocompromised patients require a 5-dose vaccine regimen (days 0,3,7,14,28) plus mandatory serologic testing to confirm adequate antibody response 2

Marijuana is Not Mentioned

Marijuana does not appear in any rabies vaccination guideline as a contraindication, precaution, or drug interaction 1, 2. The comprehensive ACIP recommendations from 1991,1999,2008, and 2010 exhaustively detail contraindications and drug interactions but make no reference to cannabis products 1.

Clinical Recommendation

Proceed with standard rabies post-exposure prophylaxis regardless of marijuana use:

• For previously unvaccinated persons: 4 doses of HDCV or PCECV (1.0 mL intramuscularly) on days 0,3,7, and 14, plus human rabies immune globulin (20 IU/kg) on day 0 1, 2
• Administer vaccine in the deltoid muscle for adults and older children, or anterolateral thigh for young children 1, 2
• Never use the gluteal area, as this produces inadequate antibody response 1, 2

Important Caveats

• If the patient is using marijuana for a medical condition requiring concurrent corticosteroids or other immunosuppressive therapy, upgrade to the 5-dose regimen (days 0,3,7,14,28) and obtain serologic testing 1-2 weeks after completion 2
• The critical factor is the underlying immunosuppressive condition or medication, not the marijuana itself 2
• Do not delay rabies post-exposure prophylaxis for any reason—rabies is nearly 100% fatal once clinical symptoms develop, and prompt treatment is nearly 100% effective 1, 3