Clarithromycin

A macrolide antibiotic, FDA-approved for respiratory, skin and ear infections, mycobacterial (MAC) infections, and H. pylori ulcer treatment in combination regimens.

psilodex.org/m/clarithromycin · data v2026.10.05

Clinical contraindication: None listed; No label contraindication covering psilocybin was found. This is not a finding that the combination has been shown to be without risk.
Psilocybin evidence: No psilocybin data
Half-life: 3–7 h; Approximate, in adults. Source under Interaction below.

Named in state rules?

Not namedColorado

Not namedOregon

PendingNew Mexico

Cite asPsilodex, “Clarithromycin”, v2026.10.05. psilodex.org/m/clarithromycin

Clinical data and state rules are separate facts. Both are shown; neither is a decision.

What it is used for

FDA status

FDA-approved

FDA-approved for

Respiratory tract infections (bronchitis flares, sinusitis, community-acquired pneumonia, strep throat)
Uncomplicated skin infections
Ear infection (acute otitis media, children)
Mycobacterium avium complex (MAC) infection treatment and prevention in advanced HIV
H. pylori infection and duodenal ulcer (with other drugs)

Sources [1]

Other safety

The label reports higher all-cause mortality 1 to 10 years after clarithromycin exposure in people with coronary artery disease, and serious reactions with several CYP3A4-metabolized drugs (e.g. colchicine, simvastatin).

About the medication itself, separate from any interaction with psilocybin.

Sources [1]

01 Interaction with psilocybin

It may slow how the body clears psilocybin by blocking an enzyme. Also, it can affect heart rhythm, and its label lists liver injury.

Detail Clarithromycin strongly inhibits CYP3A4 (a drug-clearing enzyme). CYP3A4 metabolized psilocin in lab studies (Thomann 2024). So clarithromycin may raise psilocin levels, though the body removes psilocin mainly by glucuronidation and conversion to 4-HIAA. There are no psilocybin data. It prolongs the QT interval (a heart-rhythm measure), with torsades de pointes (a dangerous rhythm) reported. Psilocybin briefly raises heart rate and blood pressure. Separately, its label also lists hepatotoxicity (liver injury). Sources [1][2]

Human data with psilocybin: No psilocybin data; based on how it works and its label
Half-life: 3–7 h (dose-dependent); active metabolite 5–9 h (FDA label, checked 2026-10-04) 3–4 h at 250 mg every 12 h; 5–7 h at 500 mg every 8–12 h. 14-OH clarithromycin 5–9 h.

Evidence types on this record

No psilocybin dataNo psilocybin data: no human data with psilocybin or another classic psychedelic; the text draws on the medication's own pharmacology and its label or reference facts

02 Pharmacology relevant to psilocybin

2 listed · counted on reports

Liver injury: The label or source warns of liver injury, from raised liver enzymes to liver failure. Liver disease also affects how the body clears psilocin. Sources [1]
QT-prolonging: Lengthens the QT interval on an ECG, a measure of the heart’s electrical recovery between beats. A long QT raises the risk of a dangerous heart rhythm, more so with other QT-prolonging drugs or low potassium or magnesium. Sources [1]

03 State rules

Plain-language summary · official text governs

CO4 CCR 755-1

Not named

No provision names this medication or its class.

Colorado · checked 2026-10-04

OROAR 333-333

Not named

No provision names this medication or its class.

Oregon · checked 2026-10-04

NM7.35.3 NMAC (proposed)

Pending

New Mexico's clinical rules (proposed 7.35.3 NMAC) are not final. No provision naming this medication has been found.

New Mexico · checked 2026-10-04

04 Conditions to ask about

None linked

No condition named in state rules is linked to this medication.

05 Sources

Clarithromycin tablets, film coated (Solaris) · FDA label (DailyMed) — revised 2026-04 | QT-prolonging: 5.2 QT Prolongation "Clarithromycin has been associated with prolongation of the QT interval and infrequent cases of arrhythmia." | Liver injury: 5.3 Hepatotoxicity "In some instances, hepatic failure with fatal outcome has been reported and generally has been associated with serious underlying diseases and/or concomitant medications." | 7 "Clarithromycin is a strong CYP3A4 inhibitor and this interaction may occur while using both drugs at their recommended doses." | 12.3 "The elimination half-life of clarithromycin was about 3 hours to 4 hours with 250 mg administered every 12 hours but increased to 5 hours to 7 hours with 500 mg administered every 8 hours to 12 hours."
Thomann J, Kolaczynska KE, Stoeckmann OV, et al. In vitro and in vivo metabolism of psilocybin’s active metabolite psilocin. Front Pharmacol 2024;15:1391689. — Abstract: "recombinant CYP2D6 and CYP3A4 enzymes metabolized nearly 100% and 40% of psilocin, respectively." "MAO-A transformed psilocin into minimal amounts of 4-HIAA and 4-HTP." "In conclusion, MAO-A, CYP2D6, and CYP3A4 are involved in psilocin's metabolism." Introduction: "Around 33% of a psilocybin dose is renally excreted as 4-HIAA."

Record history

v2026.10.02First published.
2026-10-04Last reviewed against its sources.

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